LB7 requires extended crank time to start

[chessy56]

I posted a thread several weeks back regarding a 2001 LB7 that was getting hard to start, meaning I'm seeing crank times nearly twice as long as what I've been used to having- particularly when the truck is sitting in single digit temps and below. (Used to require ~3 seconds to crank after the glow plug indicator went out; now takes 5-6 seconds). I also had the engine start normally in single digit temps, only to have the engine stop on me after 3-5 seconds of running (this has happened to me twice now; required some 20-30 seconds total of cranking to restart). The engine has 115K on it and doesn't seem to be smoking at the tailpipe, nor have I noticed any fuel in my oil. Fuel filter was changed on Jan 12th and my extended crank has persisted since then. A Tech 2 monitor shows the rail pressure coming up well past 10,000psi during the crank (regulates down once the engine starts).

Took the truck to the dealership and left it overnight for them to start. To no surprise, the low was only 15 F and it started without problems for them the next morning. I mentioned my concern about the 7year/200K mile warranty on the injectors, but they won't budge unless they can reproduce the problem (and it may not get cold enough to reproduce the problem any more this winter- don't know).

Anyway, the dealership stated that if I had an injector issue, the SES lamp would come on. Would it? If the injectors are not creating a good mist, would starting require the extra crank time I'm now experiencing? Would the PCM detect an unbalanced injector and set a DTC? Looking for a second opinion.

("Duramaster"- I left you a private message on this one).

[Jake99Z71]

Have you checked the balance rates and return rates? How old are your batteries? Take them out and have them load tested.

[madmatt]

Have you tried pumping the primer pump before trying to crank it when it's cold out and if so,,, does it seem to make a difference???

To address your questions,,, NO the ses may or may not come on. You'd ahev to have several "dripping" injectors to create an extended crank. I've seen'em fire right off w/ two dead holes. If the injecttor was bad enough to cause a miss, yes it could set an SES light.

It sounds like if it only does it when really cold you have some sort of glow plug/ intake heat problem. Have you ever had any parts replaced that pertains to those systems???

[chessy56]

I'll connect the Tech 2 again to verify the balance between the injectors. Last time I checked, they were within milliseconds of each other. Haven't checked the return flow rates (done with the Tech 2 monitor? if so, what parameter would I look for).

Load tested the batteries about a month ago: one (drivers side) was at nearly 700 amp, the other (passenger side) was down to ~560 amp (I'll be replacing that one soon).

I have not attempted to pump the primer pump prior to starting. The times I did pump it (w/o engine running) the pump appeared to go down w/o effort. Do I need to pump this thing repeatedly until I feel resistance?

A couple of years ago I had one of the glow plug relay blocks fail on me, which was announced by the SES lamp. I'll check for an open plug, but I'll offer this: I've observed the glow plug indicator lamp turn on and immediately go off as soon as I turn the ignition key, and that was with the engine plugged in over night (tells me the engine is sufficiently warm enough where the glow plugs do not need to be on). Still, I had roughly 4-5 seconds of crank before the engine fired up.

Still, what would make the engine stall (quit) after it appears to start normally? This has happens 2X within the last 2 months.....

[hrsedrvr]

i recently bought a 2001 2500HD which is having similar troubles
mine starts best when cold but still cranks too long 2-3 seconds
when hot it is about the same
the worst is after running and sits about 10-15 minutes long cranks and sometimes have to let it cool down some before it will even go
changed fuel filter and that helped some but it still is'nt righti hope it's not injectors cause i checked with dealer and warranty ran out in nov/07
been told it could be fuel pressure regulator?
been told it could be computer not delivering enough fuel at certain temps?
been told it could be aftermarket fuel filter?
also has that idle surge
works fine when running and no smoke etc.
just scrounging for ideas before i have to start paying the dealer to try and find the problem!!!!
dealer said they could run a scan for $75.00 but no guarantee that it would show anything but it could be a cheap way to find a small problem
just praying its not injectors!!

[Buck]

Do you guys use fuel additives? If not, I would STRONGLY suggest you use a GOOD quality fuel additive like FPPF total power. Treat your fuel heavy in the single digit and sub-zero temps. I've noticed ulsd is harder to treat which requires more treatment during very cold weather. Kinda sounds like border line gelling....I had an episode like you guys are having, last winter. Do you guys have your winter fronts on?