6.0 School Bus, intermittent no-start...

DamageINC · December 21, 2007

Ok, so we have an '05 short bus that just came back in. I looked at it 2 weeks ago for what they stated as a crank-no-start after the vehicle died on them. I hop in the van, turn the key - boom, fires right up.

We *know* that the fuel used in these vehicle has a very high biodiesel content, after prying the information out of the guys at the yard where they fill up the buses.. mind you, it's getting pretty damn cold out here this time of year so gelling of the fuel with high bio content is constantly in the back of my head.

Only codes in the system however were a P0231 (fuel pump secondary ckt low). Check oasis, talk to hotline, basically was told not to worry about the P0231 as long as the connections at the inertia switch were ok.

I end up replacing the fuel filters due to the history of the shitty fuel being used, and send them on their way with my fingers crossed, as I was getting absolutely nowhere trying to verify the stall and/or no-start. They were aware that this "may or may not" take care of the issue but we need to be able to verify the concern to make a proper diagnosis.

So....

Bus comes in today on the hook - "died while driving. Cranks, starts, but only runs for a split-second". Get in - verified, sure enough, cranks over, fires up for a fraction of a second, then shits out. After letting the glow plugs warm up for a good long while and cranking it some more, it starts to sound like a fuel delivery issue again, I can practically hear the injectors hammering away while cranking (and still not starting) so I decide to just call it quits there and start with the actual diagnosis.

Pull up some basic pids, B+, VPWR, FICM SYNC, SYNC, ICP, RPM, just to get started and check for obvious problems. Turn the key - boom, ICP ramps perfectly and the thing fires right up, runs like it was new. Can't get it to act up anymore.

WTF.

Pull codes, get that P0231 again (which I cleared last time) ALONG with a P2614 (CMP output ckt open) and a P2617 (CKP output ckt open).

So I've got an intermittent P0231 and now 2 other codes for cam and crank circuits, with no sign so far whatsoever of these signals dropping out and causing a loss of sync.

Just curious if anyone here has run into any similar situations, seen these codes before, that kinda thing. OASIS comes up empty. Initially I was thinking that maybe I was running into a delamination issue, but now I'm not so sure after seeing the cam/crank codes. I'm going to drop it outside for a few hours and hopefully after sitting, I'll be able to get it to act up.

What kills me is that it's dying while being driven, and then it's a crank-no-start, which definitely coincides with the P0231 and the P2614/P2617, so I'm not sure that being cold really has much to do with the issue....

Dave

Tony302600 · December 21, 2007

Arent 2614 and 1617 set when you crank the flippin truck over a million times and wont start.

If ure concerned about those codes, put the SYNC and FICMSYNC pids into a bar graph form with IDS on DATALOGGER and see if it stays at yes the whole time, if it drops out, you will see it much better then the slow to react box yes/no pid and u know u have a problem. Otherwise i've set those 2 codes when cranking a truck A LOT.

I've had a couple of 231's that ended up being a fuel pump.

If it is an extreme int no start, dies out.. i would put a engine harness and cam + crank sensors in it. ESPECIALLY in the vans. Right Dwayne.

sdtheclub · December 23, 2007

Check the wiring at the fuel pump. Had one doing the same thing and the connection at the pump was inter open. Had to replaced the short jumper harness at the pump. These are also known for the engine harness but they will only set the CMP code so I really don't think that's your problem. The CMP and CKP codes were probably set for the engine being crank over for along period of time. Good luck and let us know what you end up finding.

Keith Browning · December 23, 2007

The CMP and CKP codes were probably set for the engine being crank over for along period of time.

I also find that those codes set in many stalling situations and low RPM driveability concerns caused buy injector misses, low fuel pressure and falling ICP. That is why the PCED tells us to ignore those codes if set together and address all other DTC's and symptoms first. Personally Dave, I would be making some data recordings and looking them over.

DamageINC · December 27, 2007

Anyway, this one turned out to be a real easy one. Just got around to looking at this one again because they had us on "hold" after we mentioned it might be non-warranty.

But anyway, I went and took the thing out on the road. Ran fine but didn't accelerate for shit, foot to the floor and it was like you might as well have been at half throttle, total fuel starvation symptoms. Just put filters in it a couple weeks beforehand and it ran it's ass off before, so I just ended up yanking the tank out of it & having a look inside.

Sure enough, it looked like someone threw a handful of playground sand in the tank. It wasn't delaminating, but whatever fuel they're putting in there is just contaminated as hell with debris. Not sure if it's coming from *their* tanks or the supplier, but either way - customer pay. Getting a new sender/pickup, pump, filters, and having the tank sent out to be cleaned.

Dave

LARRY BRUDZYNSKI · December 28, 2007

Obviously they have a fleet of these "short buses", has your s/writer or manager contacted them to get them all in for this contamination problem or are they going to be like most fleets and just get pissed off as it happens? And blame Ford and the 6.0 for the no start problem. Before anybody says it... I know the problems as well as anybody with the 6.0, but you can't blame this one on it. Although you may be concerned with the lack of fuel if it did damage the fuel system.

Keith Browning · December 28, 2007

Dave, you sure it wasn't because of THIS? Although I have seen mostly F-Series aft axle tanks rust but I have seen three bus tanks do the same. Personally I think its the metal regardless of whats doin with the vent.

LARRY BRUDZYNSKI · December 28, 2007

Dave did you happen to get any of the "sand" out of the tank and verify that's what it was? Sometimes rust will look a lot like sand inside of a tank. The reason I ask is that this reminds me of when I was at the Honda dealer and went thru the 84-85 86-89 Accord filler neck recall/fuel contamination. The tanks had seems like a ton of dirt but was actually rust from the filler neck, rest at the bottom of the tank and being sucked up thru the pickup and contaminating the system.

Has anybody checked the necks on these trucks?

DamageINC · December 28, 2007

I made sure to inspect the filler neck and inside of the tank to make sure it wasn't rusting out, and both areas of concern were in good shape.

The school that owns this bus recently had their *ENTIRE* fleet of buses vandalized, ranging from over 70 slashed tires to fully spraypainted/graffiti'd, and God knows what else. There's always a possibility that this stuff was introduced into the tank by some dumbass at the school who aided in the festivities.

The only bus that survived the attack was one that I happened to be putting an STC fitting in, so it was in our shop that night /forums/images/%%GRAEMLIN_URL%%/smile.gif

Dave