Engine/Transmission (1994 - 1998) fuel press sux @ idle, fine otherwise ?????

[The patriot]

Eric,



I've been away from this thing for a few days. There is a last resort thing to do to check the pre-fuel filter system for leaks. Take it all off: steel lines, lift pump, and fuel heater/pre-filter. Put it all together and restrain the cam follower plunger with something so pressure does not pop it out of the pump. Presurize the whole mess with about 20 PSI of air. Put it in a five gallon bucket of water. I had to do that once to find the leak. It was the fuel heater in mine. Another guy found a bad fitting that looked good but many bubbles when it was in the bucket.

I'm sure glad you replied Joe, but I hope it dont lead to this.



I think I'll get a clean piece of cardboard under tomorrow, then run 5 psi to the tank for an hour or so.

Sit back in the lawn chair, have a cigar and see what happens.

I've been degreasing the heck out of this for the past few days, and it wasnt even dirty before that, if there's something leaking, I HOPE it will show up then. :{ :{

I'm ordering an overflow valve also tomorrow just because I dont want to go through all that. :{

Eric

 

[The patriot]

Just got done ordering the OF valve. The guy on the phone said it sounded like the lift pump. One of the check valves not holding.

I must admit, it strikes me as a very likley suspect, however I will exhaust all avenues before replacing it.

I'll post when I know more.

Eric

 

[ABorchard]

eric, wish I had seen this sooner. I immediately suspected the lift pump was the problem. Air or fuel leaks have entirely different symptoms, hard starting being a major one. I assume you bought the o/f valve from Marty, he has pumps for $95, best price around.

 

[Joe G.]

Eric,



You can take the lift pump apart pretty easy. Make sure you note which way the check valves face. There are three large O-rings, a couple of springs, three check valves, and a piston. If anything is scarred up the pump probably needs replaceing. I don't know of a source for the check valves so if you have a bad one you will need to replace the pump. If everything looks ok, it probably is. The lift pump is a pretty simple gadget.

 

[The patriot]

Thanks guys. I have a new lift pump in the garage, latest part #.

I had no reason to buy it at the time just turned out to be a good price and I happened to have some spare $$$.

Yea, Marty said that sometimes they dont show a problem until a fuel filter was changed. I told him that I had the fuel tank pressurised while running, he said it wont matter, just the way they are.

The part I hate is, if I didnt have a F. P. gauge, I wouldnt even be looking for something wrong. Starts/runs fine.

Guess things could be worse.

Eric

 

[ABorchard]

It may run fine right now but get on a hill with a load and I guarantee the engine will die and will be hard to restart. Been there done that, that's why I have a fuel pressure gauge.

 

[The patriot]

It may run fine right now but get on a hill with a load and I guarantee the engine will die and will be hard to restart. Been there done that, that's why I have a fuel pressure gauge.

Glad to hear that! If I was out, it would be with the 32' Wilderness in tow.

Eric