06 Short Bus - crank no-start when hot...

DamageINC · May 16, 2008

So yeah, 57k mile school bus. Towed in for a crank no start. P0341 in memory, probably front cranking it into oblivion.

Either way, I get in, it fires right up. Drive it around, monitor the usual pids, only thing I noticed was that the ECT/EOT spread got up to around 15* but that shouldn't have any effect on the starting of the engine.

Bring it back, shut it off, go to crank it over after sitting for a minute - ICP only climbs to about 280 psi. I'm pretty sure that the HPOP is fine, it had no trouble achieving 3,800+PSI during WOT stomps. I crank it over about 10 minutes later, the EOT has had a chance to cool down and it makes it up to about 350 PSI. Another 15 minutes and slooooowly built enough ICP to sputter and finally start after a 10 second crank time. Drives around mint afterward, no driveability issues. Shut down again - crank no start.

I'm wondering if maybe I've got a "loose" injector issue here, I recall reading about them but I have yet to deal with it personally. Anyone here thinking differently?

Dave

mchan68 · May 16, 2008

You'll have to air test the high pressure oil system for air leaks. With that kind of ICP reading with the engine warm, I'm guessing it would be the dummy rail lower o-ring(s). An STC fitting failure usually gives you a much lower reading. Read TSB 08-09-09.

Shlep · May 17, 2008

I had an E-series that would do the same thing you're describing and I had an STC fitting that O-rings were toast, just about to the point of total failure but enough left to make you think it was something else. After it cooled abit it would fire after an extended crank.

just something to keep in mind.

DamageINC · May 17, 2008

Well, I had some time today to dig into this one. Put shop air through the system and isolated an air/HPO leak in the left cylinder bank. Off comes the valve cover, air tested again and sure enough there was a pretty obvious leak near the front of the bank. Pulled out the oil rail, popped all 4 injectors out and inspected them to find no real damage.

I checked the "fitment" of all the injectors onto their respective nipples and all seemed to fit snug enough to be considered normal.

With the injectors in the rail, I applied some more shop air to the fitting where the lower half of the stand pipe kinda 'plugs' into the oil rail and found my leak in the oil rail itself, from the opposing plug where the standpipe would attach if the oil rail were on the other bank.

Off to get this thing on the road again.

Dave