LB7: Hard starting

[squeeky]

I am having longer cranking than usual. About 10 seconds of cranking before it will start. Just changed the fuel filter. It started before the filter was changed. Then rebuilt the filter head and chunked the plastic WIF sensor for one from merchants. Still doing it. Yesterday it would run about 25-30 seconds before it would die. I would have to prime it to get it to start. As long as I was priming it while running it would stay running. Today it started once I primed it but stayed running by itself for atleast 30 minutes before I shut it off.
I have looked for fuel leaks and see none. Didn't see any fuel in oil. No smoke. Had normal throttle response while running today. I have a ppe lift pump I am going to put on sometime this week. 101000 factory injectors.

Also getting p0621 code. Been getting it off and on for a month or so. Batteries and alt have checked good. It came on today then when I went to read it, it didn't show any codes.

Could it be injectors or cp3 going out?

 

[BlkMax]

Mine was hard starting prior to replacing my injectors (all 8). I had 4 bad ones, 2 on each side (bit the bullet and did them all). That was time 2 at 135k, time 1 was at 18K on the dealer.

I was not getting any black smoke, but had some white smoke when it started. I also had a CP3 FPR that could not keep up over about 2k rpm. The smoking could have been from the combo.

If you have EFILive, check your balance rates on the injectors.

 

[brandonkinney]

brother i'm having the same problem with my truck as well. i was told to check all fuel lines to make sure that they arent cracked allowing it to suck air. cause mine is throwing a p0087 code which is low fuel rail pressure. so good luck if you figure it let me know what you did so maybe i can try it as well to see if it fixes mine as well.

 

[BlkMax]

P0621 or P0612?

Check here for codes: http://www.duramaxdiesels.com/forum/showthread.php?t=3966

 

[DAVe3283]

What I'd do first is install the lift pump, then let the pump run with the motor off and look for leaks. Much easier to find leaks when the system is under pressure.

It may be that simple...

 

[squeeky]

I got my ppe pump installed. Once I got it running I had a small leak around my gasket of the pre oem filter. Got it tight and now it starts normal. Guess that pump helped it out :thumb: