Author: Bustekhub

J1939 CAN Network Operation and Testing

J1939:

The Society of Automotive Engineers (SAE) developed the J1939 standard to be the preferred CAN (Controlled Area Network) for equipment used in industries ranging from agriculture, construction, and fire/rescue to forestry, materials handling as well as on and off-highway vehicles and transit buses. It is a high-level protocol that defines how communication between nodes (modules) occurs on the bus. The J1939 network is a specific communication system, supporting specific sets of applications and a specific industry, rather than being generalized.


Messages:

Messages are transmitted between nodes (Modules /ECU/ ECM/TCM/PCM) at 250,000 bps. Any electronic control unit (ECU) using J1939 is permitted to transmit a message on the network when the bus is idle. Every message includes a 29-bit identifier, which defines the message priority, what data is contained within the 8-byte data array that follows the identifier, and which ECU sent the message.

 

Layout:

The J1939 layout on a vehicle consists of Backbone that extends the length of the vehicle. The Backbone consists of three wires.
⇒ CAN High + : Yellow wire transmits data
⇒ CAN Low – : Green wire transmits data
⇒ Shield – Connected to ground close to the vehicle center. It does not transmit data, but protects the CAN High and the CAN Low from RF (radio frequency) and electromagnetic interference. The wire is bare and will have aluminum foil around it. It will take any unwanted frequencies and direct them to vehicle ground.

Note: The wires are twisted to cancel out frequencies. 

 

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End of Line Resisters (EOL):

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The J1939 datalink consists of twisted yellow and green wires.
⇒The yellow wire is J1939 +
⇒The green wire is J1939 –
The J1939 datalink has two terminating resistors, one at each end of the backbone. 

The purpose of the terminating resistors is to minimize the reflections of data on the datalink. Collision of reflected data can cause J1939 messages to become partially or completely lost. Data collision can also cause the data to be erratic. Terminating resistors prevent this from occurring. Although the J1939 datalink may function with a missing or failed terminating resistor, data collision can occur and cause problems.


⇒ Each terminating resistor is 120 Ω, but the equivalent of two 120 Ω resistors in parallel is 60 Ω. With both resistors installed in the circuit there should be 60 Ω measured at any two points between J1939+ and J1939– in the circuit, such as between pins C and D of the diagnostic connector.

⇒ But if a terminating resistor is removed, the circuit resistance will be 120 Ω measured at any two points between J1939+ and J1939– in the circuit, such as between pins C and D of the diagnostic connector. 


IMPORTANT: It is essential that two terminating resistors are installed in the J1939 datalink. Numerous J1939 problems have been attributed to missing terminating resistors.

 

Diagnostic 9-pin Deutsch Connector:

Heavy duty J1939 applications use a 9-pin Deutsch connector to interface with test equipment and software to J1939. Communicating to nodes and testing the J1939 can be done through the Deutsch connector.

 

 


 

Operation and Testing

J1939 Resistance Check Operation:

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J1939 Resistance Check Open or Missing Resister:

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J1939 Resistance Check CAN High Shorted to Ground:

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J1939 Resistance Check CAN High and CAN Low Shorted:

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J1939 Voltage Check CAN High:

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J1939 Voltage Check CAN Low:

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J1939 Voltage Check Missing or Open Resister CAN High:

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J1939 Voltage Check Missing or Open Resister CAN Low:

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J1939 Voltage Check CAN High, CAN High and CAN Low Shorted:

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J1939 Voltage Check CAN Low, CAN High and CAN Low Shorted:

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Allison Transmission Gen 4 / 5 Connector Pin-Outs

Allison Gen 4 / 5:

Allison Transmissions B400R / B500R that are Gen 4 / 5, use the same style connectors for the TCM and valve body. These pin-outs are beneficial for component and harness testing.

 

 


 

Allison High Side Drivers (HSD):

 

Allison transmissions use three High Side Drivers (HSD) to energize groups of PCS (Pressure Controlled Solenoid). This minimizes wiring.

 

Once the ignition is turned on, the TCM will send power through all three HSD’s, The TCM will energize the PCS’s by sending a ground PWM (Pulse Modulated Signal) through the solenoid ground wire to complete the circuit.
⇒ The power going through the PCS’s also serve as a feedback to check the wiring and the solenoids. Since the power will back feed through the ground circuit back to the TCM.
⇒ Another thing to note is that the TCM will not log a DTC (Diagnostic Trouble Code) with the ignition on and a component disconnected, open or shorted. It will only log once the vehicle
engine is started.
⇒ Average operating voltage to PCS’s is approximately 6-7 volts.


HSD 1 – Energizes PCS-4, Main Mod and PCS-6 (Seven Speed)
HSD 2 – Energizes PCS-1, PCS-2, PCS-3 and SS1 (Shift Sol. 1)
HSD 3 – Energizes TCC (Torque Converter Clutch), SS2 (Shift Sol. 2) and PCS-5

 

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TCM 80 Pin:

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TCM 80 Pin Connector:

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20 Pin Connector to Valve Body:

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20 Pin Valve Body Connector:

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Cummins Front Crank Oil Seal Change

 

Video for seal change:  https://youtu.be/V0p5H4rV6ns

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The seal requires a plastic install sleeve that come with the seal. Front seal install tool.
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Cummins Parts

Parts breaks down and part numbers.
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Complete front seal kit.
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Torque Specs

⇒ Seal carrier nuts (flange): 71 in-lb (8 n-m)
⇒ Vibration dampener bolts: 148 ft-lb (200 n-m)

 

 


 

Front Seal Removal

1. After removing accessory drive and vibration dampener, remove the 5 seal carrier flange nuts.
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2. Pry seal carrier flange at 5′ clock position.
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3. Remove seal carrier flange and dust seal.
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4. Clean mounting surface.
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Front Seal Install

1. Apply sealer around base of mounting studs.
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2. Apply 1/8 bead of sealer around seal carrier flange.

 

3. Make sure plastic install tool is in place.

 

4. Line up seal carrier flange with plastic install tool to mounting studs, then push in until carrier flange is flush with front cover.
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5. Remove plastic install tool.
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6. Install the 5 nuts to sealer carrier flange and torque to 71 in-lb (8n-m).

 

7. Install front dust seal.
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8. Install dampener and accessory drives.
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Allison Gen 4 / 5  B400R / B500R Valve Body Assemblies

Allison Valve Bodies:

Allison valve bodies for Gen 4 / 5 are the same in layout, springs, solenoids and spool valves. But between the B400R and B500R there are differences between some springs and spool valves, but all solenoids are the same. 

For ordering parts for a transmission, use the transmission serial number to cross reference the correct parts.

 

 


 

 

Allison Valve Body Layout:

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Solenoid Valve Body Assembly:

 

 

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Main Valve Body Assembly:

 

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Diagnostic Switch PS-1:

The diagnostic switch PS-1 has two functions:


1. When the C5 clutch is filled, It verifies pressure to the C3 clutch pack in reverse, neutral, and 1st range are attained.
2. When the C5 clutch is exhausted, it verifies the positions of the C1 and C2 latch valves.

If incorrect pressure is sensed by the switch, the signal will be sensed by the TCM, and a DTC will be logged.

Note: C1 and C2 latch valves control fluid pressure between clutches. They also control limp mode operation.
⇒ PCS-2: Controls the C2 clutch pack, but in reverse it will control the C3 clutch pack.
⇒ PCS-3: Controls the C3 clutch pack, but in neutral, reverse and 1st range it will control the C5 clutch pack. The C5 clutch pack has no assigned solenoid.

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Allison Gen 4 / 5 Solenoid to Clutch Combination

 

 

 

 


 

 

Filter Life Switch PS-2:

The filter life switch PS-2 monitors filter life deterioration when the filters need replacing. When unfiltered main pressure (pressure on the outside of the filter) becomes greater than filtered lock up pressure (pressure after the filter). The unfiltered main pressure will increase and activate the PS-2 switch, sending a signal to the TCM. This signal will activate the Prognostics service icon on the shifter that filter service is needed.

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Retarder Valve Bodies:

 The retarder is a bolt on hydraulic brake at the rear of the transmission to help slow the vehicle down. The valve body receives activation commands from the TCM to apply the retarder. The PCS-5 solenoid is PWM which controls retarder application. How much retarder application, depends on driver input demand.

Note: All retarder valve mounting bolts to retarder housing are M8 bolts that are torqued at 18-21 lb. ft. (N m 24-29).
⇒ The metal separator plate between retarder valve body and retarder housing is coated with a sealing agent. No paper gaskets are used.

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Valve Body Torque Specs:

Internal valve body torque specs are as follows:

Note: Control valve body mounting bolts to transmission case and filter nuts are M10. Torque to these bolts or nuts are 38-45 lb. ft. (51-61 N m).
http://bustekhub.com/index.php/2016/08/13/allison-transmission-filter-oil-change-b400r-b500r/

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Links:

http://bustekhub.com/index.php/2016/10/08/allison-wtec-iii-gen-4-5-hardware-differences/
http://bustekhub.com/index.php/2016/08/13/allison-transmission-filter-oil-change-b400r-b500r/

http://bustekhub.com/index.php/2016/08/02/allison-transmission-shifter-functions-and-prognostics/

 

 

Cummins ISL-G Ignition System

 

The Cummins ISL-G ignition system is a capacitive discharge type. The ICM (Ignition Control Module) takes 12 volts and steps it up to 250-300 volts to the primary side of the coil. This high voltage uses less current and allows the coils to create less heat.

 


 

System Components:

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System Operation:

The ignition system is a coil-on-plug system that uses an ignition control module (ICM) to operate.
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Spark timing is controlled by the engine control module (ECM). The ECM commands the ICM to energize the ignition coil for the present cylinder in the firing sequence over the ICM timing line in the engine harness. 
The coils are energized by the ICM through the charge voltage and primary return lines in the ignition harness.
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The ECM requires an initial input from the Camshaft Speed Position Sensor for the engine to start. Once the ECM gets synchronization from this sensor and the Crankshaft Speed Position Sensor, the Crankshaft Speed Position sensor becomes the primary input for ignition timing. The ECM also uses input from the Intake Manifold Pressure Temperature Sensor to adjust how far to advance the timing of the spark.
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The engine camshaft speed/position sensor provides engine speed and cylinder #1 compression stroke information to the ECM. This sensor generates a signal from the passing of seven cast protrusions located on the rear of the camshaft gear. An engine crankshaft position sensor mounted at the rear of the block is used to signal piston position during the stroke. Both of the ISL-G position sensors are hall-effect type and provide a DC high-low (5 to 0V) signal to the ECM. The engine crankshaft speed/position sensor is located on top of the flywheel housing. The information from this sensor is used by the ECM to determine crankshaft rotational speed and each cylinder’s piston position as it relates to degrees of crankshaft rotation.
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The ISLG uses a coil-on-plug type of ignition coil. This coil mounts directly to the spark plug. The high voltage pulse from the secondary windings of the coil are delivered directly to the spark plug. Without traditional spark plug wires the system requires less maintenance and is more efficient.
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Coil Voltages


Voltages are as follows:
⇒ Primary coil side (pins A & C): 250 – 300volts
⇒ Secondary coil side (kV spark voltage): Average is 15 – 20kV, up to 40kV.


Note: Spark kV will vary with:
engine condition
spark plug condition
engine load
fuel conditions
kV readings between all cylinders should be close in value. Any cylinder(s) that kV’s are not within the value of the rest, indicate a problem with that cylinder(s).  

 

 


 

Misfire Detection:

There are two methods of misfire detection used:

 

1. The first method uses the ICM to detect a misfiring cylinder over the secondary RETURN wire in the ignition harness. The ECM receives this information from the ICM over combustion detection (misfire) SIGNAL wire(s).

2. The second method uses crankshaft speed to detect a misfiring cylinder.

The ICM monitors individual spark plug voltage and misfires and reports it to the ECM as an input for diagnostic purposes only. Ignition timing and air/fuel mixture values are not affected by these signals.

The ICM provides kV and misfire detection as an input to the ECM for diagnostic fault code capability. This engine incorporates multiple spark discharge (MSD) technology that uses solid state devices to trigger the capacitor charge/discharge cycle very rapidly when the engine has low intake manifold pressure.

During this condition, there is a relatively small amount of air/fuel mixture in the cylinder, and the cylinder is relatively cool. It is possible for the flame created by the spark to extinguish, due to the low heat and sparse air/fuel mixture in the cylinder.

 

Misfire and spark plug kV readings can be monitored with Cummins Insite software.
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Possible causes for misfires:

Spark plugs past maintenance intervals
Damaged spark plugs or boots
⇒ Spark plugs not torqued properly
Malfunctioning coil
Shorted or open ignition harness

 

Misfires can send unburned fuel and oxygen to the catalytic converter, overheating it and damaging the substrate. Any misfires should be addressed to prevent progressive damage from occurring. 

 


 

Knock Detection:

Knock detection is used for engine protection:

The knock sensor is an accelerometer which measures high frequency vibrations.  The electronic control module (ECM) processes the voltage signals from the knock sensor to check for an elevated signal during the combustion cycle for each cylinder. They are two wire sensors.
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The ISL-G has two knock sensors, each sensor monitors three cylinders. The location of the knock sensors is specific and the knock detection is calibrated for this position, therefore, knock sensors must not be repositioned from the original location. The knock sensors are located near the front and rear of the engine.

⇒ The front knock sensor listens to cylinders 1,2,3 for detonation.
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⇒ The rear knock sensor listen to cylinders 4,5,6 for detonation.
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The sensors are piezoelectric type that produce a small AC current when the crystal inside vibrates with engine detonation. When detonation is sensed, the ECM retards engine timing until detonation is diminished. Over time, the ECM will attempt to restore normal timing if detonation diminishes. The ECM has three thresholds programmed into it for knock detection and prevention.

Light Knock: Lowest of the three thresholds, is designed to guard against damage from light to mild knock. The ECM will retard ignition timing and slightly de-rate the throttle. A yellow lamp will illuminate to warn the operator that light knock has been detected.

Heavy Knock: This warning will be activated if the light knock protection fails to eliminate the problem or a knock is detected that crosses the heavy knock threshold. The ECM will trigger a severe throttle de-rate and illuminate the red warning lamp.

Cold Knock Threshold: This provides severe protection while the engine is reaching a stable operating temperature. Time at this threshold is a function of coolant temperature at startup. The cold knock threshold is disabled when the engine temperature reaches 160°F (71°C).

 

 


 

Troubleshooting:

Ignition system problems can be categorized into three areas:

1. No Starts – this is a engine crank no start condition. This is the easier ignition system condition to troubleshoot as the fault is active. 

2. Misfires – Can be random and on one or multiple cylinders,

3. Knock Faults – These are harder to troubleshoot as conditions like overhead out of adjustment, air compressor timing, low cylinder compression, turbocharger, defective plugs and other ignition components may be the culprit.

 

NO START Troubleshooting:

The recommended practice to troubleshoot the system for a “NO START” conditions is to follow the OEM diagnostic procedures. In lieu of this; the steps below are steps that we have found to work during our troubleshooting of failed systems.

Step 1Determine if the coil is generating spark.

To determine if an ignition coil is operational and producing the high voltage required to create a spark at the plug, an ignition tester is recommended. this could be one of two:

 A spark indicator – this tool gives you a good indication of the system working to produce voltage. Unfortunately, it is not a good indicator of the intensity of the spark. 

 A Cummins approved ignition spark tester, for the ISL-G engine, the COP must be kept nearly vertical during operation due to oil-filled cooling of the coil. The test kit adapter must be used to properly position the COP during spark testing on this engine. When using this tester, no attempt should be made to adjust the tester. The ignition coil tester is preset and is not adjustable. Attempts to adjust the tester will damage the tool.
Note: Follow Cummins recommended procedures on using the tool.
Cummins 4918343, Cummins Ignition Tester, Cummins ISL-G, ISL-G, Cummins

If a spark signal is being generated by the coils; the problem may be faulty spark plugs or internal engine damage. In very few cases the fault may be the ICM is incorrectly timing the firing sequence.

 

Step 2 –  Determine if the coil is being charged by the ICM.

Check for charge voltage to be present at terminals A (charge voltage 250-300 volts) and C (secondary return) of the coil. This is the voltage supply from the ICM to charge the coil. If there is no voltage here; the ICM is not sending the signal to charge the coil,  this may be due to missing timing signals, missing or inadequate power supply to ICM, or defective ICM.
Caution: Use caution when checking coil voltages, high voltage can cause a dangerous electrical shock.

Cummins ISL-G, ISL-G, ICM, CNG, Cummins Ignition, Cummins Ignition Coil

 Step 2 – cont.
Checking voltage at ICM C1 connector
 Check for battery voltage at terminal 1 (switched power +) of the C1 connector, this should be vehicle voltage of 12 volts. This test must be done by back probing the connector to ensure that any harness resistance is detected. It is often found that voltage is low or missing here; mostly on NABI buses due to corroded or loose connections.
 Check for battery ground to be present at terminal 2 (return –) of the C1 connector. Once again the connector must be back probed to get accurate readings.
Note: Voltage reading can be done between pin 1 and 2 of the C1 connector at the ICM. Never measure voltage with connector disconnected, readings will not be accurate.

Cummins ISL-G, Cummins ICM, Cummins Ignition System, Cummins Ignition Power

 


 

 

Resistance Checks

Coil Resistance:

Primary resistance measurement of the coil taken between terminals A and B. The reading should be less than 2 ohms, if coil resistance is greater than 2 ohms, replace coil.
Cummins ISL-G, Cummins, Cummins Coil, Cummins Ignition System, Cummins Ignition, Cummins, Cummins ICM

 

⇒  Secondary resistance winding measurement for the COP resistance is taken between pin C of the 4-pin connector of coil and spark plug connector. The reading should be less than 20K ohms, if coil resistance is greater than 20K ohms, replace coil.
Cummins ISL-G, Cummins, Cummins Coil, Cummins Ignition System, Cummins Ignition, Cummins, Cummins ICM

 

Harness Resistance

⇒  The end to end resistance of any of the wires in the ignition harness should be less than 10 ohms.
Note: Readings greater than 10 ohms, harness should be repaired or replaced.
The resistance of any wire to chassis ground should be 100K ohms or more, considered shorted to ground.

Cummins ISL-G, Cummins ICM Harness, Cummins Ignition Harness, Cummins Harness Resistance
Sample: Harness end to end resistance test

 


 

MISFIRE and KNOCK Troubleshooting:

Misfiring and Knock Fault conditions are harder to troubleshoot. Drive the vehicle in the conditions of normal operation: engine temperature, road condition, acceleration rates, passenger loads.

Knock Sensor – The sensor itself rarely fails, and typical failures may include:
Loose sensor connector
Corroded or damaged harness pins
 Damaged wiring harness
Loose sensor mounting
Wrong location installation

Keep in mind that the knock sensors measure the high frequency vibration of the engine due to combustion knock. Knock may occur if the engine is supplied low quality fuel or if operated at excessive temperatures.
Other sources of high frequency vibration that may also cause knock faults include gear-driven components like air compressors or hydraulic pumps, driveline vibration, or a rough running engine due to low fuel pressure.
When the conditions exist, knock faults typically will occur when operated at full power, such as during wide open throttle acceleration. 

Cummins prefers that you troubleshoot the knock sensors through INsite; very few details are given about the operation of the sensor.

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 The knock sensor is specifically designed for each particular engine and is not an interchangeable component.
The Cummins Knock sensors is biased at 2.5 volts, this means that the ECM provides a voltage on the signal line.
This is done to avoid noise and interference associated with all ground circuits. The sensor itself divides the bias voltage in half because of its internal resistance. The knock circuit due to its higher voltage level (bias voltage) will not pick up any ground noise interference.
The bias voltage also lets the ECM know when the knock sensor circuit has either open or short circuited.
When the sensor detects engine knock, it drops the voltage down to a lower level; the ECM sees this as noise and de-rates accordingly.
Cummins ISL-G, Cummins, ISL-G, Cummins Knoch Sensor, Cummins Knock Voltage, Cummins Knock

 

Knock Sensor Resistance

Cummins does not provide a resistance value for the sensor. But when measured the sensor reads 4.880M ohms.
Note: High engine harness resistance will also influence sensor reading, and may cause a fake knock code reading or false codes. Harness resistance must be less than 10 ohms for each individual circuit.
Cummins ISL-G, Cummins, ISL-G, Cummins Knock Sensor, Knock Sensor, Cummins Knock

 


 

Component Connector Views and Pin-Outs

 

Cummins ISL-G, Cummins, ISL-G, Cummins Ignition System, Cummins Ignition, Cummins ICM, Cummins Ignition Layout, Cummins Coils

 

 

Cummins ISL-G, ISL-G, ICM, CNG, Cummins Ignition, Cummins Ignition Coil

 

Cummins ISL-G, ISL-G, ICM, CNG, Cummins Ignition, Cummins Ignition Coil

 

Cummins ISL-G, ISL-G, ICM, CNG, Cummins Ignition, Cummins Ignition Coil

 

Cummins ISL-G, ISL-G, knock sensor, cummins knock sensor

 

Cummins ISL-G, ISL-G, knock sensor, cummins knock sensor

 


 

Component Locations

senosr, gas mass flow, mass air flow, knock sensor,

 

Cummins ISL-G, cummins, Cummins Coil, Cummins Ignition system

 

Cummins ISL-G, Cummins, ISL-G, Cummins Ignition System, Cummins Cam Sensor, Cam Sensor

 

Cummins ISL-G, Cummins, ISL-G, Cummins Ignition System, Cummins Crank Sensor, Crank Sensor

 

Cummins ISL-G, Cummins, Cummins Ignotion, Cummins Knock Sensor, Knock Sensor, Cummins Knock Sensor 1 2 3, ISL-G

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Cummins ISL-G Facts and Specifications

History:

The Cummins L series engine is a straight 6 cylinder engine started in 1982 as the L10 engine. It displaced 10.0 liters (610 cu. In.) in a diesel configuration.
In 1992 the L10 was introduced in a CNG (compressed natural gas) configuration and was designated the L10G.
In 2001 the L10G was replaced by Cummins Westport L-Gas Plus which was 8.9 liters (540 cu. In.) CNG engine was a collaboration with Westport Innovations.
In 2007 the L-Gas Plus was replaced by the Cummins Westport ISL-G which was 8.9 liters (540 cu. in.) CNG engine which was also a collaboration with Westport Innovations.
In 2016 Cummins Westport introduces the Cummins ISL-G Near Zero (NZ) engine. It is 8.9 liters (540 cu. in.) CNG engine. It meets and exceeds the EPA and CARB emissions standards.

 


 

Cummins Designators:

ISL-G = Interact System. Interact System meaning that the engine is capable of interacting with the transmission and other electronically controlled devices in the truck or bus.
L = L series engine line. Which includes L10, L-gas Plus and ISL-G.
B = B series engine line. This includes 3.3, 3.9, 4.5, and 5.9 liter engines. These engines are offered in electronic models and fully mechanical models. The 5.9 liter engine is offered in both automotive and industrial versions.
C = C series engine line, which is the 8.3 liter engines. They are available in both fully mechanical and electronic versions with industrial and automotive versions.
E = An older engine designator which meant the engine was electronically controlled.
Q / QS = Quantum System. Signifies that an industrial engine is electronically controlled.
K = K series engine line, which includes 19, 23, 38, 45, 50, and 60 liter engine models.
M = M series engine line which would be the M11 engine. This is an 11 liter engine that came in industrial and automotive versions.
N = N series engine. Which included NTA855 and N14 engine series that came in industrial and automotive versions.
T = T series engines. The T designates the electronic controlled engine. Example QST30. But, in a mechanically controlled engine, the T designates Turbo. Example 6BT
X = Series engine line, which are the 15 liter engines only. Industrial and automotive versions available.

 


 

Engines:
Cummins Westport ISL-G

Cummins Westport ISL-G is a spark ignition stoichiometric engine. It has an exhaust gas recirculation (EGR) for emissions for NOx (nitrogen oxide) reduction. It uses an EGR cooler to lower to lower combustion temperatures and knock tendency.

ISL-G Specs:

⇒8.9 liter (540 cu. in.) inline 6 cylinder
⇒4 stroke cycle, spark-ignited, turbocharged, charge air cooler(CAC)
⇒Bore and Stroke 4.49 in. X 5.69 in.
⇒Firing order 1-5-3-6-2-4
⇒Oil capacity 7.3 U.S gallons / 29.2 Quarts
⇒Dry weight 1,625 lbs. / 737 kg.
⇒Emissions: EGR and Three Way Catalyst (TWC)
⇒Valve lash cold:
Intake – 0.014 in. (0.355 mm)
Exhaust – 0.030 in. (0.762 mm)
⇒Fuel types: CNG, LNG and Bio-methane.
⇒Three Way Catalyst (TWC) after treatment.
(It does not require Diesel Exhaust Fluid (DEF) or what is known as UREA.)

 


 

Ratings:

 Engine  Advertised HP (kW) @ RPM  Peak Torque lb-ft (Nm) @ rpm Governed speed 
 ISL-G 320  320 (239) @2000  320 (239) @2000  2200 rpm
  ISL-G 300  300 (224) @ 2100  860 (1166) @ 1300  2200 rpm
  ISL-G 280  280 (209) @2000  900 (1220) @ 1300  2200 rpm
  ISL-G 260  260 (194) @ 2200  660 (895) @1300  2200 rpm
  ISL-G 250  250 (186) @2200  730 (990) @ 1300  2200 rpm

 

Maintenance:

 Item  Distance  Hours  Months
 Oil & Filter*  7,500 mi (12,000 km)  500  6
 Fuel Filter  15,000 mi (24,000 km)  1,000  12
 Coolant Filter  7,500 mi (12,000 km)  500  6
 Spark Plugs**  22,500 mi (36,000 km)  1,500  18
 Coolant Change  30,000 mi (48,000 km)  2,000  24
 Valve Adjustment***  30,000 mi (48,000 km)  2,000  24
Air Cleaner Follow manufacturers published recommendation

*Use oil approved for CNG engines
** Service intervals vary based on average speed of vehicle, which increase or decrease intervals
***Initial valve adjustment at 1,000 hours.
 


 

Cummins Westport ISL-G Near Zero (NZ)

Cummins Westport ISL-G Near Zero (NZ) was introduced in 2016. This engine was certified by the Environmental Protection Agency (EPA) and Air Resources Board (ARB) of California for meeting the 0.02 g/bhp-hr optional Near Zero NOx (nitrogen oxide) emission standards for medium duty truck, transit bus, school bus and trash truck. The engine is a spark ignition stoichiometric burn. It has an exhaust gas recirculation (EGR) for emissions. It uses an EGR cooler to lower to lower combustion temperatures and knock tendency.

ISL-G Near Zero (NZ) Specs:

⇒8.9 liter (540 cu. in.) inline 6 cylinder
⇒4 stroke cycle, spark-ignited, turbocharged, charge air cooler(CAC)
⇒Bore and Stroke 4.49 in. X 5.69 in.
⇒Firing order 1-5-3-6-2-4
⇒Oil capacity 7.3 U.S gallons / 29.2 Quarts
⇒Dry weight 1,625 lbs. / 737 kg.
⇒Emissions: EGR and Three Way Catalyst (TWC)
⇒Valve lash cold:
Intake – 0.014 in. (0.355 mm)
Exhaust – 0.030 in. (0.762 mm)
⇒Fuel types: CNG, LNG and Bio-methane.
⇒Closed Crankcase Ventilation (CCV) system that prevent crankcase emissions from going to atmosphere.
⇒Three Way Catalyst (TWC) after treatment.
(It does not require Diesel Exhaust Fluid (DEF) or what is known as UREA.)

 


 

Ratings:

 Engine  Advertised HP (kW) @ RPM  Peak Torque lb-ft (Nm) @ rpm Governed speed 
 ISL-G 320  320 (239) @2000  320 (239) @2000  2200 rpm
  ISL-G 300  300 (224) @ 2100  860 (1166) @ 1300  2200 rpm
  ISL-G 280  280 (209) @2000  900 (1220) @ 1300  2200 rpm
  ISL-G 260  260 (194) @ 2200  660 (895) @1300  2200 rpm
  ISL-G 250  250 (186) @2200  730 (990) @ 1300  2200 rpm

 

 

Maintenance:

 Item  Distance  Hours  Months
 Oil & Filter*  7,500 mi (12,000 km)  500  6
 Fuel Filter  15,000 mi (24,000 km)  1,000  12
 Coolant Filter  7,500 mi (12,000 km)  500  6
 Spark Plugs**  22,500 mi (36,000 km)  1,500  18
 Coolant Change  30,000 mi (48,000 km)  2,000  24
 Valve Adjustment***  30,000 mi (48,000 km)  2,000  24
Air Cleaner Follow manufacturers published recommendation

*Use oil approved for CNG engines
** Service intervals vary based on average speed of vehicle, which increase or decrease intervals
***Initial valve adjustment at 1,000 hours.

 

 

 

Cummins ISL-G Engine Control System

The control system for the ISL-G engine is a closed loop control system. The electronic control module determines the controls the throttle plate and fuel control valve to provide the correct air/fuel ratio based on driver demands. Upon initial starting the engine remains in open loop for about 2 minutes before going into open loop.

Some of the sensors shown here may not apply to the engine you are working on. The ISL-G engine is built with several potential sensor configurations, such as: two possible EGR pressure differential sensors, two possible intake humidity temperature/pressure sensors, two possible aftertreatment sensors, and two possible crankcase pressure sensors, among many others.

 


 

INPUT SENSORS

Accelerator Pedal Position Sensors

The accelerator position sensor is a Hall Effect sensor attached to the accelerator pedal. The accelerator position sensor varies the signal voltage to the engine control module (ECM) as the accelerator pedal is depressed and released. The accelerator pedal contains two position sensors, these sensors (1) and (2) are used to measure the pedal position.  The signal voltage for accelerator position 1 is twice as much as the signal voltage from the accelerator position 2. The accelerator pedal position circuit contains an accelerator pedal position 5 volt supply, accelerator pedal position return, and accelerator pedal position signal.
Sensor is located at foot pedal assembly, no adjustment or calibration is needed.

TPS, ISL-G, Cummins, Cummins TPS
 

 

After-treatment (Oxygen) Sensors

The engine control module (ECM) uses the after-treatment exhaust gas oxygen sensor 1 to determine the composition of the exhaust gas and then, to adjust fueling when operating in closed loop. The ECM uses the after-treatment exhaust gas oxygen sensor 2 to measure catalyst efficiency. The 4 wire sensors haves a built-in heater to help maintain proper sensing element temperature.
The engine turbocharger outlet oxygen sensor 1 is located in the exhaust system, downstream of the turbocharger.
The after-treatment exhaust gas oxygen sensor 2 is located in the vehicle exhaust system, just downstream of the after-treatment outlet.

O2, Oxygen Sensor, Cummins, ISL-G
 

 

 

Camshaft Position Sensor

Provides engine speed and position to the ECM. The electronic control module (ECM) provides 5 volt supply to the camshaft position/speed sensor on sensor supply circuit 1. The ECM also provides ground to the return circuit of the sensor. The camshaft position/ speed sensor provides a signal to the ECM on the engine camshaft position/speed sensor signal circuit.
The camshaft position/ speed sensor is located on the intake side of the engine above the accessory drive above the air compressor drive. (see here) 

Cummins ISL-G, ISL-G, Cam position sensor

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Coolant Level Sensor

The engine coolant level sensor provides a signal to the ECM of the coolant level in the expansion (surge) tank. The electronic control module (ECM) supplies a 5 volt supply to sensor using a common sensor supply circuit. The ECM also provides a ground on the sensor return circuit.
⇒ The engine coolant level sensor is typically located in the radiator top tank or surge tank.

Cummins, ISL-G, Coolant Level, Cummins ISL-G
 

 

 

Crankshaft Position Sensor

Provides engine speed and position to the ECM. The electronic control module (ECM) provides 5 volt supply to the crankshaft position/speed sensor on sensor supply circuit 1. The ECM also provides ground to the return circuit of the sensor. The crankshaft position/ speed sensor provides a signal to the ECM on the engine crankshaft position/speed sensor signal circuit.
It is located on the intake manifold side of the engine between cylinders 5 and 6 at crankshaft level. (see here)
Cummins ISL-G, ISL-G, crank position sensor

 

 

Crankcase Pressure Sensor

The pressure inside the crankcase filter is measured by the crankcase pressure sensor. When the crankcase pressure sensor determines the crankcase pressure is higher than normal, this fault code is logged.
The crankcase pressure sensor is located on the crankcase ventilation filter.

 

 

EGR Differential Pressure Sensor

The exhaust gas recirculation (EGR) differential pressure sensor has two ports that sense exhaust pressure. This sensor signal voltage changes based on the differential pressure in the EGR crossover tube. The EGR differential pressure sensor measures the exhaust gas pressure drop across the EGR differential pressure orifice. This pressure drop is used to estimate the amount of EGR flow into the intake manifold.
The sensor is located near the EGR valve on top of the fuel housing. (see here) 
Cummins ISL-G, ISL-G, EGR, EGR pressure sensor, EGR delta pressure

 

 

EGR Valve Position Sensor

The exhaust gas recirculation (EGR) valve is opened by a motor located on top of the EGR valve. A motor shaft extends from the motor and contacts the dual-poppet valve to open the EGR valve. The EGR valve motor does not actually retract the EGR valve. The motor current is reduced and the spring pushes the EGR valve closed. The EGR valve motor contains three position sensors that detect the location of the EGR valve. These sensors report the position of the valve back to the ECM over the EGR valve position A, B, and C wires.
⇒ The EGR valve is located on the air intake connection, on top of the intake fuel module. (see here) 
Cummins ISL-G, ISL-G, EGR motor, EGR sensor, ISL-G EGR

 

 

EGR Temperature Sensor

The exhaust gas recirculation (EGR) temperature sensor is a variable resistor sensor and is used to measure the temperature of the EGR gas flow after it exits the EGR cooler. The ECM monitors the change in voltage caused by changes in the resistance of the sensor to determine the EGR flow temperature. The EGR temperature value is used by the ECM for the engine protection system.
⇒ The EGR temperature sensor is located on the EGR connection tube between the EGR cooler and the air intake connection. (see here) 
Cummins ISL-G, ISL-G, EGR temp sensor, ISL-G EGR

 

 

Engine Coolant Temperature Sensor

The engine coolant temperature value is used by the ECM for the engine protection system and emissions control. The sensor is a variable resistor sensor that is used to measure the temperature of the coolant in the engine. The ECM monitors the change in voltage caused by changes in the resistance of the sensor to determine the coolant temperature.
⇒ The coolant temperature sensor is located below the exhaust manifold port for cylinder number 1. (see here)
Cummins ISL-G, ISL-G, coolant temp, Cummins coolant temp

 

 

Intake Manifold Temperature/Pressure Sensor

The intake manifold temperature/pressure sensor provides a signal to the ECM on the intake manifold pressure sensor signal circuit. This sensor signal voltage changes based on the pressure in the intake manifold. The engine intake manifold pressure/temperature sensor is a combination sensor that also measures intake manifold temperature.
⇒ The sensor is located on the back of the fuel module near the fuel pressure regulator end cap and fuel shutoff valve. (see here) 

Cummins ISL-G, ISL-G, intake manifold temp pressure sensor

 

 

Gas Mass Flow Sensor

The gas mass flow sensor measures the amount of fuel flowing into the engine. The ECM adjust the fuel control valve based on this measurement.
⇒ The gas mass flow sensor is located on the fuel housing. (see here) 
Cummins ISL-G, ISL-G, Gass mass flow sensor, Cummins gas mass flow

 

 

Humidity Sensor

The electronic control module (ECM) uses the engine turbocharger compressor intake humidity/temperature sensor to measure relative humidity. The engine turbocharger compressor intake humidity/temperature sensor is a combination sensor and is also used to measure the temperature of the air entering the turbocharger compressor.
⇒ The engine turbocharger compressor humidity/temperature sensor is located in the turbocharger compressor inlet elbow.

Cummins ISL-G, ISL-G, Humidity sensor, Humidity pressure sensor

 

 

Knock Sensors

The knock sensor is an accelerometer which measures high frequency vibrations. The electronic control module (ECM) processes the voltage signals from the knock sensor to check for an elevated signal during the combustion cycle for each cylinder. One sensor can be used for multiple cylinders.

Knock is a combustion phenomenon where the end gases in the combustion chamber are compression ignited. Once ignition occurs, local combustion rates are very fast, resulting in pressure oscillations in the combustion chamber. These oscillations can result in an audible knocking or pinging sound. The oscillations are accompanied by increased heat transfer and higher surface temperatures which can result in engine damage.

Knock is initially controlled by making adjustments to the base spark timing table.  In order to prevent engine component damage caused by timing adjustments, there is a maximum limit programmed into the ECM. When timing adjustments are unsuccessful, there are two throttle de-rates utilized to eliminate knock.
⇒ Mild de-rate (25%)

⇒ Severe de-rate (65%)
The 25% de-rate limits throttle until knock is eliminated, 65% severe de-rate limits the throttle even further.  If the severe de-rate occurs enough times, the throttle is limited to a maximum severe limit until the engine is keyed off.
Knock sensor 1 is located on the side of the engine block, above the air compressor, and mounted in the lower of the two holes near cylinder number 2. (see here) 

⇒Knock sensor 2 is located on the cylinder head above cylinder number 6. (see here)

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Cummins ISL-G, ISL-G, knock sensor, cummins knock sensor

 

Mass Air Flow Sensor

The air flow on most late model engines is calculated through the engine control module (ECM), it uses engine coolant temperature, engine throttle position, intake manifold pressure and temperature, humidity, and engine rpm to calculate the air flow into the engine.
⇒ Mass air flow sensor is located on the air intake adapter just before the throttle plate actuator. (see here)
Cummins ISL-G, ISL-G, mass air flow, cummins mass air flow

 

Oil Pressure Sensor

The engine oil pressure sensor provides a signal to the ECM on the engine oil pressure sensor signal circuit. This sensor signal voltage changes, based on the pressure in the oil rifle. The ECM will detect a low signal voltage at operating conditions when the oil pressure may be slightly lower. The ECM will detect a high signal voltage during high engine speeds or operating conditions when the oil temperature is low.
⇒ The oil pressure sensor is located on the engine block, under the ECM. (see here) 
Cummins ISL-G, ISL-G, oil pressure sensor, cummins oil pressure sensor

 

Engine Fuel Regulator Intake Pressure Sensor (Primary Fuel Pressure Sensor)

The engine fuel regulator intake pressure sensor provides a signal to the ECM on the engine fuel regulator intake pressure sensor signal circuit. This sensor signal voltage changes, based on the pressure of the fuel entering the engine (low-pressure) regulator.
The fuel pressure sensor is located on the low fuel pressure regulator housing near the fuel inlet fitting toward the rear of the engine. (see here) 

Cummins ISL-G, ISL-G, fuel pressure, Inlet fuel pressure, cummins inlet fuel pressure
 

 

Fuel Outlet Pressure/Temperature Sensor ( Secondary Fuel Pressure Sensor)

The engine fuel regulator pressure/temperature sensor is a variable resistor sensor and is used to measure the temperature of the fuel exiting the low pressure regulator.  The ECM monitors the change in voltage caused by changes in the resistance of the sensor to determine the fuel temperature.
The engine fuel regulator outlet pressure/temperature sensor is located in the fuel housing near the gas mass flow sensor. (see here) 
Cummins ISL-G, ISL-G, fuel pressure sensor, cummins fuel pressure, secondary fuel pressure

 

Throttle Intake Pressure Sensor

The throttle intake pressure sensor monitors the pressure of the air after the turbocharger compressor outlet. The intake manifold pressure sensor monitors the absolute pressure of the air and fuel mixture in the intake manifold, after the engine throttle valve. The turbocharger compressor intake humidity/pressure/temperature sensor monitors the absolute pressure, temperature, and humidity of the air before the turbocharger compressor inlet. This sensor is standard on newer ISL G engines. Older engines have an analog turbocharger compressor intake humidity/temperature sensor and a separate air inlet restriction sensor.

The throttle intake pressure sensor is located on the air inlet adapter, immediately before the throttle body. The turbocharger compressor intake humidity/pressure/temperature sensor, or optional air inlet restriction sensor, is located on the air inlet connection, immediately before the turbocharger compressor inlet.
The intake manifold pressure/temperature sensor is located on the air intake manifold, directly above the fuel control housing. (see here) 
Cummins ISL-G, ISL-G, mixer intake pressure sensor, Cummins throttle intake pressure sensor

 

 

Turbocharger Compressor Intake Humidity/Temperature Sensor

The engine turbocharger compressor intake humidity temperature sensor is a variable resistor sensor and is used to measure the temperature of the air entering the intake of the turbocharger compressor. The ECM receives sensor information thru J1939.  The engine turbocharger compressor intake humidity/temperature sensor is a combination sensor and is also used to measure the specific humidity of the air entering the intake of the turbocharger compressor.
The engine turbocharger compressor intake humidity/temperature sensor is located on the turbocharger compressor intake elbow.
Cummins ISL-G, ISL-G, Humidity sensor, Humidity pressure sensor

 

Turbocharger Compressor Intake Pressure Sensor

The engine turbocharger intake pressure sensor provides a signal to the ECM on the compressor intake pressure sensor signal circuit. This sensor signal voltage changes, based on the pressure of the atmosphere.
⇒ The engine turbocharger compressor intake pressure sensor is located just prior to the intake of the turbocharger compressor.
Cummins, Cummins ISL-G, ISL-G, Turbo intake sensor

 

Turbocharger Turbine Intake Temperature

The engine turbocharger turbine intake temperature sensor is a variable resistor sensor and is used to measure the temperature of the exhaust gas entering the turbine of the turbocharger.  The ECM monitors the change in voltage caused by changes in the resistance of the sensor to determine the temperature of the exhaust entering the turbine. The ECM uses the engine turbocharger turbine intake temperature sensor for engine protection purposes.
⇒ The engine turbocharger turbine intake temperature sensor is located in the turbocharger turbine housing.
Cummins, Cummins ISL-G, ISL-G, turbo temp sensor, Turbo intake temp

 

Throttle Position Sensors

There are two throttle position sensors located inside the engine throttle actuator and they share a common supply and return. The electronic control module (ECM) controls the engine throttle actuator, which is both an input and output device.
⇒ The engine throttle actuator is located between the air intake adapter and the fuel control housing. (see here) 
Cummins, Cummins ISL-G, ISL-G, throttle plate, throttle sensors

 


 

Actuators

Engine Fuel Shut-Off Valve

The engine fuel shutoff valve is a normally closed solenoid that is control by the ECM to shutoff the flow of gas to the engine. The ECM will open the valve when it detects engine rpm.
⇒ The valve is located on the back of the fuel module, near the fuel pressure regulator end cap. (see here) 
Cummins, Cummins ISL-G, ISL-G, fuel shut off, Fuel valve

 

EGR Valve

The EGR valve controls the amount of recirculated exhaust air entering the fuel mixer. The valve is controlled by the ECM with input from the differential and valve position sensors.
⇒ The EGR valve is located on the air intake connection, on top of the intake fuel module. (see here) 
Cummins, Cummins ISL-G, ISL-G, EGR valve, EGR, EGR position sensor motor

 

Fuel Control Valve

The fuel control valve is regulated by the ECM to control the amount fuel entering the mixer.  The ECM precisely determines the amount the valve should be open under operating conditions by inputs from the aftertreatment (oxygen) sensor, mass air flow sensor, and the gas mass flow sensor.
⇒ The fuel control valve is located in the fuel housing next to the gas mass flow sensor. (see here) 
Cummins, Cummins ISL-G, ISL-G, fuel control valve, fuel valve

 

Throttle Plate Actuator

The throttle actuator controls the position of the throttle plate.  The electronic control module sends a pulse width modulated signal to the actuator which in turn opens or closes the throttle plate. The electronic control module uses the measured position of the throttle plate from the position sensor to control fueling.
⇒ The engine throttle actuator is located between the air intake adapter and the fuel control housing. (see here) 
Cummins, Cummins ISL-G, ISL-G, throttle plate, throttle sensors

Wastegate Control Valve

The electronic control module  uses the engine turbocharger wastegate control valve to control the pressure in the diaphragm canister of the turbocharger actuator. The turbocharger actuator is connected to the turbocharger wastegate.
⇒ The engine turbocharger wastegate control valve is located on the air inlet adapter block just upstream of the throttle and connected by a tube to the turbocharger actuator. (see here) 

Cummins, Cummins ISL-G, ISL-G, wastegate control, wastegate

 

Wastegate Actuator

The wastegate actuator on the turbocharger, controls boost pressure by holding the wastegate closed until maximum boost is reached.
⇒ The wastegate actuator is located on the turbocharger.

 

 

 


 

 

Controllers

ECM (Electronic Control Module)

The engine control module (ECM), is the main computer for engine performance and drivability functions. The ECM takes the information from the various sensors on the engine, and uses that information to calculate and tune engine spark and fuel for maximum power and efficiency.
⇒ The ECM is located on the intake side of the engine. It is bolted to the engine block and is below the fuel intake module. (see here) 

 

 

Ignition Control Module

The ignition system is a coil-on-plug system that uses a separate Ignition Control Module (ICM) to operate the ignition system. The electronic control module sends timing information to the ignition control module.  In addition to the timing information, the electronic control module also sends firing commands to the ignition control module.  The ignition control module then sends firing signals to the individual coils.  These firing signals are approximately 300 volts.
⇒ The ICM is located next to the ECM on the intake side of the engine, near the flywheel housing. (see here) 

 

senosr, gas mass flow, mass air flow, knock sensor,
Cummins Engine Intake Side View
coils, ignition coil, EGR cooler, knock sensor
Cummins Engine Top View

 

 

Current Measurements:
Current measurements are very helpful when troubleshooting electrical circuits. The current rating of components can be used to determine their condition. Current measurements allow you to determine the current draw as the component operates.

The engine starter, for example, will draw more than the rated current when overloaded, this higher than rated current flows usually indicates a problem which can cause additional problems. 

 


 

Inductive Current Clamps:

Most Digital Multi-Meters (DMM) or Digital Volt Ohm Meter (DVOM) only measure DC/AC current up to 10 A. For higher measurements an inductive clamp must be used, which measures current from .01 A to 1000 A, it does so by measuring the strength of the magnetic field around a conductor.  Some current clamps can measure AC currents only, which is not useful in vehicle applications. Ensure that the one you use or is capable of both AC and DC.

The clamps use Hall Effect sensor to measure the strength of the magnetic field produced in a ring of material that is temporarily placed around the current-carrying wire to measure DC. The greater the amount of current flowing in the wire, the stronger the magnetic field that is produced in the ring. To measure AC the clamp acts as part of a transformer to produce a measurable value.

 


 

Current clamps are a standalone accessories for your DMM or built into multi-meter:

Standalone clamps output a voltage value per measured amp. Most clamps have an output of 1 millivolt per amp. If the multimeter shows a measurement of 10 millivolts, the current flowing in the wire is 10 amps. If the voltage displayed on the multimeter is 100 millivolts, the current flowing in the wire is 100 amps.

In clamps that are built into a multimeter, measuring the current flow is as easy as selecting ‘current’ on the function selector, the value is then displayed in amps.

amp clamp, current probe, fluke
Fluke Amp Clamp (standalone)
Fluke Built-in Current Clamp
Fluke Built-in Current Clamp

 


 

 

Setting Up to Measure with Standalone Clamp (clamps that produce voltage): 

1. Turn the dial to mVac for ac current, or to mVdc for dc current on DMM.
2. Plug the black test lead into the COM jack.
3. Plug the red test lead into the V jack.
4. Zero the clamp by rotating the “zero” knob (some clamps do not require adjustment). Adjust until reading is on or close to 0mV.

 

current clamp, fluke clamp, current probe
Zeroing Clamp

5. Position the clamp over the conductor to be measured. With some clamps current flow orientation must be followed, point the arrow on the clamp towards direction of current flow. To prevent the clamp from picking up stray magnetic fields, separate the test conductor from surrounding conductors by a few inches. If separation is not possible, take several readings at different locations along the same conductor. Do not measure shielded conductors, as the magnetic fields are greatly diminished or even eliminated.

Note: Make sure circuit is energized to perform test.

Current Clamp Setup
Current Clamp Setup

6. View the reading in the display. On some DMM’s the mV scale only reads up to 600mV, if you expect to read a higher amp value change the setting to the Vdc scale and take your reading there. ensure to keep track of prefixes to the measured value.

current probe, amp measurement, amp draw, starter draw
1 to 1 conversion

Good Luck!

 

 

 

 

 

Description:

The Vapor door motor is an air-operated geared differential device with two horizontally opposed cylinders of different diameter size. A rack gear connects the pistons within the cylinders, the rack gear meshes with a rotary gear to convert straight line motion of the pistons into rotary motion. This rotary motion will rotate the teeter plate which moves the connecting rods to operate the doors.

Vapor, Doors, Assembly
Vapor Motor Door Assembly

 

 

 


 

 

Operation:

The Vapor differential motor operation:
1. To close the bus door, the large cylinder is charged with air thru an air solenoid, the large piston overcomes the air pressure in the small piston moving the rack gear to close the doors. The rate at which the door closes, depends on the closing speed adjustment and how air volume is allowed to the cylinder.

Vapor, door, differential
Door closing, large piston overcomes small piston to close door.

 

2. To open bus door, air to the large piston is shut off. The small piston being pressurized with air, will push towards the large piston. This will cause the air in the large piston to exhaust and cause the door to open. The rate of opening speed is controlled by the opening speed adjustment, by controlling the air exhaust rate.

Vapor, differential, motor
Door opening, air is exhausted from large piston side, this allows small piston to open door.

 

3. Cushioning effect, is used to control the doors from slamming when opening. As the large piston comes to end of it’s opening stroke, the remaining air will exhaust thru the cushioning orifice. How much cushioning depends on the cushioning adjustment.

Vapor, motor, differential
Cushioning adjustment controls the doors from slamming open.

 

 


 

Adjustment:

Door motor adjustments should be performed with a minimum of 90 psi. to get the proper adjustment speeds.
The required cycle time for opening or closing of doors is 2.5 to 3 seconds.
Always start with closing speed, since this affects the door opening speed.
All door hardware must be checked for wear or binding before motor adjustments are performed.
Wear eye protection.

Caution: Adjustment screws are not captive, and if they are unscrewed to far out with air pressure, they can become projectiles. 

 

Tools:

⇒ 5/32 Allen wrench
⇒ Flat blade screwdriver
⇒ 1/2 Wrench

Adjustments should be done in the following order:

Vapor, Closing speed, opening speed, cushion adjustment
Vapor differential motor adjustment order

1. Closing Speed: Loosen closing speed jam nut and use 5/32 Allen wrench to adjust closing speed.
Turning screw in (clockwise) will decrease closing speed.
Turning screw out (clockwise) will increase closing speed.
Closing speed should be approximately 2.5 – 3 seconds. After adjustment is done tighten jam nut, recheck closing speed.

 

2. Opening Speed: Loosen closing speed jam nut and use 5/32 Allen wrench to adjust opening speed.
Turning screw in (clockwise) will decrease closing speed.
Turning screw out (clockwise) will increase closing speed.
Opening speed should be approximately 2.5 – 3 seconds. After adjustment is done tighten jam nut, recheck opening speed. Disregard door slamming when opening, cushion adjustment will control this.

 

3. Cushion Adjustment: Loosen cushion adjustment jam nut and use flat blade screwdriver to adjust cushion speed to prevent door from slamming open.
Turning screw in (clockwise) will decrease dampening speed.
Turning screw out (clockwise) will increase dampening speed.
The cushioning adjustment is designed to affect the last quarter of the door travel on the opening cycle only. Opening speed may have to be readjusted to get the best combination of opening speed and cushion adjustment. Once adjustment is done, re-tighten cushion jam nut.

Recheck closing, opening and cushion adjustment. Check that all jam nuts are tight.

Allison WTEC III & Gen 4 / 5 Hardware Differences

 

Facts:

WTEC I,II,&III series – Late 1990’s discontinued after Gen 4 around 2006
Gen 4 – July 2005
Gen 5 – December 2012
GM sold Allison – August 2007 for 5.6 billion.
Allison 1000/2000 are the Chevy/GMC Duramax that are light duty transmissions.
Allison 3000/4000 are the medium and heavy duty transmissions used in transit buses.
⇒All of the Gen 4 and up Allison transmissions use the same TCM.
Allison DOC will troubleshoot all versions of Allison transmissions.
Allison Gen 4 / 5 require an electrical break out box to troubleshoot transmissions.
⇒The difference between Gen 4 / 5 is a newer style TCM and Shifter, mechanically same.
⇒Latest Version is Allison DOC 14.0

 

 


 

 

Specs:

 B400R                 3000 Series
B = Bus / R = Retarder
This Transmission is mainly used in 35 ft, 40ft, and 45 ft. buses. The retarder is a hydraulic
braking system used to help slow the bus down to save on brake wear.

 

Versions:
WTEC III (Discontinued, but service and parts are available)
Gen 4
Gen 5

 

⇒Weight: 700 lbs.
⇒2” shallow sump
⇒26 quarts total (excluding external components)
⇒16 quarts service fill (drain and filters)
⇒Torque converter ratio –  4:18

 


Transmission Ratios
1st – Range: 3.49 : 1
2nd – Range: 1.86 : 1
3rd – Range:  1.41 : 1
4th – Range:  1 : 1
5th – Range:  0.75 : 1
6th – Range:  0.65 : 1
Reverse – 5.03 : 1

 

 

Transmission Identification (TID)
WTEC III: TID 3

Gen 4: TID A
Gen 5: TID A
Note: ECU/TCM TID must match transmission harness TID to operate.

 

 

B500R                  4000 Series
B = Bus / R = Retarder

This Transmission is mainly used in 60 ft. articulated buses. The retarder is a hydraulic
braking system used to help slow the bus down to save on brake wear.

 

⇒Weight: 950 lbs.
⇒2” shallow sump
⇒43 quarts total (excluding external components)
⇒30 quarts service fill (drain and filters)
⇒Torque converter ratio –  5:21

 

Versions:
WTEC III (Discontinued, but service and parts are available)
Gen 4
Gen 5


Transmission Ratios
1st Range: 3.51 : 1
2nd Range: 1.91 : 1
3rd Range:  1.43 : 1
4th Range:  1 : 1
5th Range:  0.74 : 1
6th Range:  0.64 : 1
Reverse:   -4.80 : 1

 


Transmission Identification (TID)
WTEC III: TID 3

Gen 4: TID A
Gen 5: TID A
Note: ECU/TCM TID must match transmission harness TID to operate.

 

 


Clutch Combinations and Planetaries:
B400R / B500R
WTEC III, Gen 4 and Gen 5 all have the same clutch combinations. They all also use three planetaries P1, P2 and P3.
Allison, B400R, B500R
Allison B400R / B500R Cut Away


Note: B400R and B500R have the same layout for clutches and planetaries.

Neutral:       C5
Reverse:     C3 – C5
1st Range:  C1 – C5
2nd Range: C1 – C4
Lock Up =   LU
2nd Range: C1 – C4 – LU
3rd Range: C1 – C3– LU
4th Range: C1 – C2– LU
5th Range: C3 – C2– LU
6th Range: C4 – C2– LU

 


Solenoid to Clutch:
B400R / B500R
WTEC III and Gen 4 / 5 have different solenoid to clutch combinations and the shift valve bodies are completely different.

Allison, WTEC III Valve body
Allison WTEC III Solenoid to Clutch Combinations
Allison, Gen4, Gen5, Valve body
Allison Gen 4 / 5 Solenoid to Clutch Combination

ECU / TCM Types:
Allison ECU / TCM types vary with models. Verify ECU / TCM by checking the Calibration Identification Number (CIN) on the ECU / TCM tag to match the unit being replaced. If tag is missing or damaged, connecting the ECU / TCM to Allison DOC software will display the CIN number. Verifying the CIN number is the best way to assure the correct ECU / TCM is being installed into the vehicle, since mix up do occur.
Allison, WTEC III, Gen 4, Gen 5, ECU, TCM
Allison ECU / TCM Types

 

Allison DOC CIN Numbers Identify Program in ECU / TCM
Allison DOC CIN Numbers Identify Program in ECU / TCM

 

 


Allison Shifters:

Allison shifters completely differ between WTEC III and Gen 4 / 5, and are not interchangeable between versions. Gen 4 / 5 shifters are interchangeable between those two versions.

Allison, Shifter, WTEC III, Gen 4, Gen 5
Allison Shifters

 

 


Allison Valve Bodies:

Allison valve bodies between WTEC III and Gen 4 / 5 differ greatly in electronics and hydraulic flows.

Allison, B400R, WTEC III, Valve body
Allison B400R WTEC III Valve Body

 

allison, B400R, Gen 4, Gen 5, Valve body
Allison B400R Gen 4 / 5

 

Allison, WTEC III, Valve body
Allison B500R WTEC III

 

Allison, Gen 4, Gen 5, Valve body
Allison B500R Gen 4 / 5

 

 


Allison B400R Integrated Cooler:

Allison B400R Gen 5 has an option to have a bolt on integrated cooler rather than a remotely mounted unit.

Allison, Oil Cooler
Allison B400R Integrated Oil Cooler

 

 


Resource Links:

Helpful resource links –
http://bustekhub.com/index.php/2016/08/02/allison-transmission-shifter-functions-and-prognostics/
http://bustekhub.com/index.php/2016/08/13/allison-transmission-filter-oil-change-b400r-b500r/
http://www.allisontransmission.com/

https://www.youtube.com/watch?v=RiMRytjuQLw