Intermittent Starter abort

[mattmatt14]

Hello everyone. I'm having some trouble diagnosing an issue on a friend's truck. It's a 2010 1500 5.7 2wd. Note: apparently the engine was replaced with a used one, there was an aftermarket alarm system that was removed, the ckp was replaced, and the starter is new.

The issue: when cranking, intermittently, the starter bumps the engine a few degrees and then aborts. It bumps the same amount of rotation every time. If I attempt to start the truck enough, it will eventually turn over and start. When it does start, it runs perfectly. There are no codes in the PCM or wcm. I have a reverse light circuit open code and a wiper code in the tipm.

If I jump the starter relay and have someone turn the key to start, the truck starts every time. (Me thinking it's either PCM ground supply or tipm power supply to the relay coil)
If I supply external ground, bypassing the PCM relay control, it still intermittently bumps. (Ok it must be the tipm)
If I supply external power, bypassing the Tipm relay control, it still intermittently bumps.
If I disconnect the starter solenoid, the PCM and tipm will energize the relay every time.
So the relay control cuts out immediately only when the engine starts to spin. Why?

When I monitor the pids in the tipm I don't see anything out of the ordinary. The transmission range sensor shows proper position and switches fine, the ignition switch also shows proper position and switches fine and the truck is detecting the key. No security light on or flashing. I had the tipm and PCM apart, all the connections look good. Internally, the boards look fine with no corrosion, damage, or smell.

If anyone has had this issue or if anyone has a direction I should look towards I would appreciate the assistance.

 

[Ken226]

Have you tried swapping in another relay?

 

[mattmatt14]

Yes. I've tried a different relay, different battery, and cleaned all of the grounds.

 

[Ken226]

Yes. I've tried a different relay, different battery, and cleaned all of the grounds.

In that case, the next logical place to look is the TIPM.

In a 2013+, the BCM and wiring from the BCM to the Power Distribution Center would also play a role and be in the equation.

But in your 2010, the TIPM handles all those functions and there is no BCM.

Pull the TIPM then inspect it and the connectors for corrosion. It's a common issue. Especially if you live in the northeast.

 

[mattmatt14]

In that case, the next logical place to look is the TIPM.

In a 2013+, the BCM and wiring from the BCM to the Power Distribution Center would also play a role and be in the equation.

But in your 2010, the TIPM handles all those functions and there is no BCM.

Pull the TIPM then inspect it and the connectors for corrosion. It's a common issue. Especially if you live in the northeast.

I've had the TIPM removed already and pulled it apart. I did not see any sign of damage. I also inspected the connectors and the pins are all clean and still in position. I know about the TIPM issues with these trucks but I'd just hate to throw a part at it and it not be it.

 

[jws123]

I've had the TIPM removed already and pulled it apart. I did not see any sign of damage. I also inspected the connectors and the pins are all clean and still in position. I know about the TIPM issues with these trucks but I'd just hate to throw a part at it and it not be it.

The ignitions fail often if you wiggle the key or hold it up or down will it start? also you can repair your TIPM if it winds up being the issue just solder in a new relay.