Engine/Transmission (1994 - 1998) Really High Fuel Pressure And How It Affects Performance?

[CEdwards]

I was driving along today and all of a sudden my truck wouldn't idle too good and was running rough and I looked down at the fuel pressure gauge. It had 55 psi. It never runs good so this was nothing new except for the high fuel pressure. I kept restarting it and trying to keep it running. Several times it jumped up to 100 psi and the injector pump would clatter and it would kill the engine. once it even pegged the gauge all the way around. The first thing I looked at was the overflow valve. When I took it off the pressure still wouldn't blead down past 50 psi on the gauge. I thought that was odd and the gauge must be bad. When I took the ball and spring out of the overflow valve I noticed the ball had worn a deep pocket off center and was stuck. I had to tap it out. This is one of those $35 diesel performance ones with less than 10000 miles. I put it back in with no ball and still had the same pressure. Next I took the gauge off and bled it down and it went to 0. nothing wrong with the gauge. Next I took the rubber part of the return line off of the braided line end and started the truck. It ran and idled perfect with the fuel running all over the ground. Put it back together because I had to get to work. Obviously the steel line to the tank is plugged and I will replace it with hose tommorrow. Then on my way to work running 60 psi the engine did all its usual bad things except it was worse than usual. I didn't know if i was going to make it. Then somehow on the way when i was coasting because it kept dieing I went to shift into neutral to restart it and the detent on the shifter broke. Does anyone understand how high fuel pressure makes it run so bad? and i'm going to search on here about the shifter problem if anyone has worked on it before or can point me toward a good thread about it. thanks.

 

[Joe G.]

I replied to your post in the "what's wrong" thread about the shifter.

 

[Heepdriver]

I have noticed latly that my fuel pressure has all of a sudden gone way up to about 55PSI. I have the noise but not the stalling or poor performace issue. I only have a 60# guage but I think it has pegged. I thought it was due to the home heating or bio I have been putting in the tank. But the last two fill ups have been good diesel and are still doing it. Has something happend to the diesel sence the hurricane? With bio I was seeing less fuel pressure than with regular diesel.



Thanks