Engine/Transmission (1998.5 - 2002) fuel tank pressurized, hard starting...

[Mark_Kendrick]

I have a really wierd set of symptoms that seem to be related.



MY '00 2wd Auto QC had a fuel leak at the tank a day or two ago right after I filled it up. I've had a broken gauge as long as I've owned the truck. I figured this was an excuse to finally fix it... $60 for the sender or $285 for the sender and intank LP. Before I got the chance to get the part I now have an intermittent hard start problem. I figued I may be getting a bit of air in the fuel system (from the suspected leak). I also picked up a slight miss at idle... not too alarming given the frigid weather over the past 5 days.



I stopped at the Snap-on truck today and left the truck running. When I came back to the truck I heard a hissing sound from the fuel cap. Upon opening heard a loud WHOOOOOOOOOOOOSH (long too ). With the truck Idling and the cap off the fuel tank looks like a small exhaust pipe on a cold morning... white/blueish fumes.



I had a buddy rev the truck the tank is pressurized faster at high rpm than at idle.



The only thing on the truck that could generate that kind of volume is the engine. I don't know exactly how but it has to.



I suspect a cracked head that is pressurizing the fuel return port in the head. It would explain the hard start... pressurized fuel system would have aeration in the fuel, the miss... a lot like a blown head gasket sometimes acts.



Does anyone have any idea what this might be?



The head is on the top 5 most expensive and PITRA to replace parts on the truck.



HELP!!!



Thanks,

Mark

 

[Bob4x4]

put a piece of clear tubing in the return line to view what is happening there.



Bob

 

[C.Solomon]

Speaking of taping in to the return line why not put a pressure gauge on it and see how much pressure you have.



You getting any blow by?



Pull the dip stick while its running and see whats up, check your coolant also.

 

[Nyoest]

Could be a bad injector?

 

[Mark_Kendrick]

The tank is VENTED. If U got a hissing sound check for a red cap on the vent tube on top of the fuel tank module. There is a TSB out for that, check @ Geno's for it. Poke a paper clip to check that the vent is clear. I ran a piece of tubing from the vent and let it hang down so that it will not get filled with dirt. There should be no hissing sound. Does your truck start OK with the fuel cap removed?

It's about 30* out right now but I'll check that as soon as the temp comes up.

Could be a bad injector?

Hadn't thought of that. Easy enough to check

put a piece of clear tubing in the return line to view what is happening there.

Also an excellent Idea.

 

[Mark_Kendrick]

It was the washer under the #6 injector. I removed the injectors when #6 came out it was covered in carbon. The washer stayed in the head. It was a bit of a pain to retrieve.



I had a spare set of 150hp edm's just 'laying' around . Dropped them in, busted it off and no lopey idle and no hissing fuel tank



In retrospect it should have been obvious what the problem was. I was a bit freaked by the shear volume of fumes coming out of the fuel tank.



The truck has minor egt issues now. I was forced to put a boost reference to the wastegate to keep from pegging the 60# boost gauge. The 38mm gate is enough to control boost on HY9/KSB2 twins. I can keep boost down to ~45psi or nail a 60# gauge before I get out of first gear.



Later,

Mark

 

[Nyoest]

Glad ya got it lined out. Durn shame ya had to swap them sticks though :-laf

 

[Mark_Kendrick]

It was heartbreaking to HAVE to swap them out :-laf. I hadn't done it sooner because the truck ran so well with 80hp injectors, EZ, and twins. It should have been ~350 hp and had NO egt problems.



I suppose I'll have to swap in an HX35 for the HY9. The EGTs will drop a lot and the new injectors will make the 12cm 35 spool more like the HY9 on the small injectors.

 

[Underwood Tire]

It was the washer under the #6 injector. I removed the injectors when #6 came out it was covered in carbon. The washer stayed in the head. It was a bit of a pain to retrieve.



I had a spare set of 150hp edm's just 'laying' around . Dropped them in, busted it off and no lopey idle and no hissing fuel tank



In retrospect it should have been obvious what the problem was. I was a bit freaked by the shear volume of fumes coming out of the fuel tank.



The truck has minor egt issues now. I was forced to put a boost reference to the wastegate to keep from pegging the 60# boost gauge. The 38mm gate is enough to control boost on HY9/KSB2 twins. I can keep boost down to ~45psi or nail a 60# gauge before I get out of first gear.



Later,

Mark

i just pulled the head off a 02 because of the #6 copper seal (could not retrive it). what is causing this problem?

 

[Mark_Kendrick]

i just pulled the head off a 02 because of the #6 copper seal (could not retrive it). what is causing this problem?

I wish I knew. I just wonder if it will happen again.