06 3500 Cummins Auto 4x4.. Truck suddenly died while driving, no sputtering, no stumbling, just died.. now won't start.

a. I checked fuel at the filter, and the rear pump is definitely filling the bowl.
b. Fuel is good.
c. The PCM is throwing no codes. No check engine lights.

The engine won't even sputter at all when trying to start.

My thinking? PCM, Crank Sensor, something electrical is not telling the High Pressure fuel pump/or injectors to fire.

The weird part is NO CODES. Any ideas???

Thanks!

 

Turn the key on, then bump the starter. You should hear the lift pump kick in and stay kicked in. Open the drain and see how much fuel comes out the drain. If it's not a lot, pump is shot.

 

i checked that.. lift pump is good.. it fills up the filter housing fast without hesitation.. would a cam sensor or crank sensor cause this?

 

My guess FCA on the CP3 is gone. However, I don't have a way to test it to verify.


I have read somewhere that you can unplug the FCA and it it starts then it is bad. However, I don't know this to be a fact.

 

i just ran a scan tool on it while cranking the engine.. fuel pressure setpoint varies between 2900-3700 and I'm getting 0-75psi on the fuel pressure sensor.. this means..

FCA or Injector Pump? Thanks,

 

Could be connector tube, cracked or stuck injector, fca, pump, lift pump.
Have you checked lift pump volume? I've seen trucks fail to start at 200mL in ten seconds. That's a good puddle from the water drain. Just because it fills the filter housing dosent assure that's enough for correct operation but generally wont just fail you'll know its not running well. Injectors will cause a large loss of rail but generally it will set a code for rail to low for to long while cranking. Pumps generally don't just instantly fail for the most part. I would do a return volume test and use a block off to eliminate one injector at a time until the return drops or the truck starts.


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thanks good info there. i'll try that. the thing that has me puzzled is how it just died while driving. it was not a sputter-sputter-die.. it was just driving fine.. then DEAD. Like something electrical just died.

 

I've had a few injectors do the exact same thing. You could try and replace the fca but personally I would feel you might be humping the gun a bit. However in some cases (without the tools to make checking return easy ) it may be quicker to stick one in just to check first. I honestly would look to injectors first. I've got a couple used known good fca's if that helps.

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The block off is 3164325 from cummins iirc.

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Turns out it is a bad CP3 Pump. Amazing.. only 70k miles on it..