2008 3500 6.7 Cummins diesel intermittent crank

[Kmccord]

I have an 08 3500 with dpf deletes using EF live, this truck has been running great after the deletes, but after three months I noticed the truck cranks perfect when the engine temp is cold, but run it to operating temp and kill it, go into a store come out 10-30 minutes later and the truck is hard to crank. In the beginning it would act like it was starving for fuel, however, now it will crank for about 2-3 seconds and stop, no power to the starter, switch it off and try again, it will do the same, do this about three to five times in a row then finally it will start and run fine. Has anybody had an issue with the starter stop engaging after a few seconds of cranking? The mechanic has had it for two weeks, he has swapped out the TPIM module, no change, then tried the ignition switch, no change, changed the key module, no change at this point he is at a standstill, any ideas would be much appreciated.

Thanks
Keith

 

[sag2]

It sounds like you have high resistance to ground in any of the battery cables ot in the transmission control circuits. Here is a good explanation of the possible condition. Many a TIPM has been replaced because of this high resistance condition. If you don't understand how the neutral safety circuit works the technician assumes it is the TIPM because it appears that the TIPM is turning off the starter relay. In fact it is, but only because it saw the range sensor indicate the vehicle was no longer in park or neutral. If you can't measure the voltage drop across the circuit the best course is to REMOVE AND CLEAN all grounds including the battery cables ON BOTH ENDS, and the TRS connectors.

Click No-Start is an unofficial name of a condition that is possible on some Chrysler brand vehicles. The name “Click, No-Start” comes from the click sound that is sometimes present and reported when the vehicle does not start. Due to variations between vehicles however, the click sound is not always present, even when the no start condition is present.
The condition described here occurs when a ground offset between the Powertrain Control Module (PCM) ground and the engine/transmission ground exceeds a certain threshold. The ground offset is typically caused by loose or corroded attachment of the negative ground cables or minor degradation of the negative ground cables. The condition does not necessarily occur because of added resistance at one specific place but may be a result of stack up of resistance at multiple places on the vehicle.
On Chrysler brand vehicles where the PCM also incorporates the Transmission Control Module (TCM) the PCM monitors the transmission gear position. This is accomplished by a Transmission Range Sensor (TRS) located inside the transmission. The TRS is attached to the transmission valve body. The TRS connects to the PCM with four sense circuits. The PCM supplies voltage to the four sense circuits and monitors the voltage. Based on the gear position selected, the TRS grounds the individual sense circuits. Depending on which circuit is high (12 volts) and which circuit is low (0 volts) the PCM determines the actual transmission gear position selected. For starting the vehicle, the transmission must be in either the Park or Neutral position.
As a requirement of starting the PCM performs an addition verification to determine Park or Neutral gear position using the T41 range sensor circuit. To verify Park or Neutral and allow starting, the PCM must see a low state (low voltage) on the T41 circuit. The threshold for this low state is considered to be 1.9 volts however the actual threshold could be as low as 1.4 volts. This means if the voltage on the T41 circuit exceeds 1.4-1.9 volts the PCM will sense the vehicle is not in Park or Neutral and therefore not allow starting.
When added resistance is present in the battery cables, some of the available battery voltage drops proportionately at each point where resistance is present. This voltage drop condition will increase as the current load on the battery cables increases. When the driver attempts to start the vehicle the current load on the battery cables will be at its greatest. If resistance is present on the negative cables, the engine/transmission ground will have a voltage above that of battery negative. If this voltage offset exceeds the above mentioned threshold starting will not be permitted.
In most cases on vehicles that exhibit this condition the ground voltage offset will be below the threshold when the vehicle is at rest. This permits the PCM to see the Park/Neutral position. When the ignition is turned to the start position the starter begins engagement. The moment the starter begins to engage the current load on the battery cables also increases causing the ground voltage offset to exceed the threshold. This causes the PCM to sense the transmission is no longer in Park/Neutral and disallow the starting. This partial but interrupted engagement of the starter or starter solenoid is one of the sources for the click sound.
Proper diagnosis should include measuring the voltage on the T41 circuit. In most vehicles with an NGC PCM the T41 circuit is in cavity 27 of the PCM C4 connector (may be C3 pin 27 on RFE). Using the NGC breakout box place the positive lead of a DVOM to the T41 circuit. Connect the negative lead to the battery negative post. Monitor the voltage under the following conditions. Repeat the testing as necessary to get consistent results.
• Ignition On, engine not running, electrical loads turned on
• Ignition On, engine running, electrical loads turned on.
• Starting the vehicle.
It may be beneficial to use the min/max feature of the meter. If the meter reading exceeds 0.5 volts excessive voltage drops are present even if the vehicle starts. Service the vehicle grounds as necessary to reduce the measured value as low as possible. Less than 0.1 volts is preferred. Adding redundant grounds may be beneficial both for testing and for repair.
If the sensed voltage on the T41 circuit remains high and no excessive resistance can be detected anywhere on the battery ground cables this could indicate added resistance in the TRS contacts or circuits. If necessary, these should be closely inspected.

 

[Kmccord]

Thanks for the information, however, since this is a standard and not an automatic transmission, does the above still apply?

 

[sag2]

I have never checked it on a manual, but I suppose if it grounds the clutch switch in the releaded position it would do the same thing as a range sensor. If the clutch switch is intermittant the same will happen, the TIPM will turn off the starter.
Measure the voltage on the clutch switch while it happens with a meter that has a MIN/MAX setting and you can rule it out.

 

[Adjclark]

What was the end diagnosis on his problem? I’m having a very similar problem and am baffled!