I was pulling my 5th wheel trailer when I started to get some intermittant engine cut-out at WOT (no smoke) after a downshift to pull a hill. It was worse the next day (still 1,000 miles from home), so I changed the fuel filter. I bled the lines on top of the filter and it restarted without hardly a burp. Went 500 miles without any problem-plenty of power. After a fuel stop, it just spun over and didn't fire instantly like it usually does. After 15-20 secs of cranking, it started to hit and then took off on all six. I let it set for a couple of hours during lunch; now it cranks but won't fire at all. I bled the lines at the filter and one of the injectors and it took off again (still 100 miles from home), thinking perhaps some air had gotten in somehow. Had to shut it off one more time prior to getting home, and had to repeat the previous proceedure to get it going. Got it home, and wouldn't start even with bleeding the lines. Replaced the fuel filter again, had mechanic-friend come over and re-bleed the lines at the filter and the injection pump, and return line bayonet fitting. Doesn't appear to be any fuel coming from injector lines, as we had all of them loose except #2. Haven't put a gauge on the LP, but there's a fountain of fuel coming out of the top of the filter mount when one of the brass plugs is removed and the LP is cycled. We're scratchin' our heads wondering what to do next. One odd thing: when replacing the fuel filter for the 2nd time, there was an o-ring just sitting on top of it, but it was not one of the three sizes you replace with the filter. Don't know where it came from, or if it has anything to do with the problem. 135,000 trouble-free miles on the truck. Also: the check engine light is OFF. Sorry this is so long!

 

A similar problem occured once with my '96 (2V), wound up being the fuel return line was leaking and the sending unit in the tank also needed replacement. Good luck--perhaps someone else knows how to est for this problem?

 

Have you checked for codes? I wonder if it will give you the dreaded VP code. Since you have fuel at the VP then it sounds a lot like the VP.
Tom

 

Thanks, Tom...no, we haven't checked for codes as the light isn't on, but I suppose that is next. I did print out the code list from elsewhere on this site, though. Am also going to recommend to my mechanic/friend that we do a pressure/volume test on the LP.

 

If you are getting reasonable flow out of the top of the canister housing and nothing out of the lines, or very little at the injectors, you best start shopping for your VP.

 

UPDATE: Our initial check for codes gave us these: P0121, P0234, P1693, P0216, and P0230. Cleared the codes, and never had any set again throughout our check out. LP produced approx 3 cups of fuel in 23 seconds. Fuel pressure 10-11 psi with LP cycling, and falls to 2-3 psi during cranking. Checked front of pump and gear is turning. With LP cycled on (but not cranking) fuel flows coninuously out of injector line #3. None of the other injector lines are "spurting" during cranking. NOTE: We do have a known fault in the APPS, which we were going to replace when we got home. OUR QUESTION: Have we missed anything in checkout, and can we be certain we're dealing with a pump failure? Thanks to ya'll for the feedback!

 

I kinda figured you would have the deaded PO216 code. Go here to see what they mean: http://www.obdii.com/codes.html Keep us informed.
Tom

 

Is that '0-ring" about 1/8 to 3/16 tall and about 1/8 thick. I wondered why that one was in the filters under the shrink rap, till I found one stuck to the top of my last filter when changing it. It must go up onto the nipple that the filter screws onto, so dummy me finally replaced it with a new one the filter also has the o-ring at the top like and oil filter and also the o-ring at the bottom for the water sensor, just my .02 worth, but hey, I'm learning every day, like don't have 3500# in the bed, nail it on the on ramp to I-20 and get in traffic, then it go dead as a nail, that fricking wire on the fuel shut off, stalled traffic for a few, flipped a few off with the universal HELLO sign, unplugged and plugged it back in, and back going down the road . THAT little problem is gonna be fixed in the morning, and for that FURD that tooted the horn at me, may the fleas of 1000 dogs infest your armpits, after they take a dump in your fuel tank.

 

Thanx, Pump Daddy. This o-ring was sitting on top of the filter when I pulled it down out of the housing. It is a different size than the two that go on the filter itself, or on the spindle the retaining bolt screws into. The rubber on cross-section is about 1/8", the o-ring itself is 1" OD. I'd hate to put the dollars into a new pump because a 50-cent o-ring was out of place!