Engine/Transmission (1994 - 1998) fuel pressure help

[kenny61]

ok trying to get truck back on road. bringing it to front end shop truck loses power up slight grades and dies, restarts pretty easy. thinking fueling problem installed fuel pressure gauge with snubber and isolator. in driveway i am getting between 7lbs at idle and 10lbs revved up. when i shut it off gauge stays at whatever it was reading at shutdown. is this normal? what pressures should i have?

 

[Bob4x4]

way low........20-30 psi stock

 

[kenny61]

thank you very much

 

[BigPapa]

I'd check the OFV before replacing the lift pump. Since you have a gauge hooked up, clamp the return line off with a pair of vice grips and something to keep from damaging the hose and see if the pressure goes up. If it does, it's probably the OFV. The spring in the OFV should be 1/2" long. If not, stretch it out and check the pressure.

If pressure doesn't increase while clamping the return line it's probably your lift pump.

 

[kenny61]

pressure went up to 30-40 lbs when i put a vice grip on it. should i just stretch the spring or get a new ofv? i want a permanent repair

 

[kenny61]

screw it ordered new one from larry bs

 

[BigPapa]

screw it ordered new one from larry bs

Good job. That would be best. Stretching the spring is just a band aid.

 

[GAmes]

Those snubbers give false readings in a lot of cases. My electric gauge sender is attached to a needle valve on the end of a grease pump flex hose. The valve is ever so slightly cracked open. In your case a new OFV should solve the problem.

 

[kenny61]

Ok put the new ofv in today 20 psi at idle drops as revs go up. Thinking lift pump no good but just figure I'll try something and make sure. Crimp off return line and pressure goes up to 40 at idle 60 at sustained hi rev. When I pay with revs it drops to 40 before climbing back up.


Help me!

 

[kenny61]

With out line crimped when I revit it drops to zero. With line crimped the pressures are higher with the new ofv but still not within specs

 

[GAmes]

What kind of OFV did you install? Have you read Joe G's fuel system write up?

 

[kenny61]

Larry b.s. and no

 

[GAmes]

Did you buy the adjustable one? Mine came with a loose locknut. Did you ditch the snubber?
http://www.cumminsforum.com/forum/94-98-engine/58777-joe-gs-fuel-system-writeup.html

 

[kenny61]

Non adjustable and put a snunobber on the inlet side for the fuel pressure gauge

 

[GAmes]

Instead of the snubber I recommend a needle valve barely cracked open. Like I said, snubbers give false readings.

 

[kenny61]

Ok maybe I should just drive it lol

 

[kenny61]

Ok drove it a few miles pressure still goes down to 0 when accerating but runs fine held it to floor and started to stumble let off and pressure went back up. Runs fine normal driving even with gauge reading 0. Any ideas?

 

[BigPapa]

If I were you I'd replace my lift pump at this point. Do yourself a favor and get the studs to go back with.

 

[kenny61]

If I were you I'd replace my lift pump at this point. Do yourself a favor and get the studs to go back with.

thanks that was my thought too. i did it years ago. refresh my memory about the studs please

 

[BigPapa]

I would go here. Comes with the studs from Geno's. The studs replace the bolts that hold the pump on. Just MUCH easier to install the pump with the studs. Just screw them in the holes for the bolts with a bit of thread locker.

https://www.genosgarage.com/product/pump-4988747-kit/fuel-pumps