Engine/Transmission (1998.5 - 2002) Incredibly high fuel pressure reading

[slowneasy]

I have a mechanical FP gauge w/o an insolator that seems to perform/work properly in tempertures above 40? but below that the pressure can climb way above "normal" to the point were I've seen in "peg" the gauge. After the temperture warms up it returns to normal. Any ideas what may be causing this?

Thanks!

 

[Oil Burner]

What type of fuel pump do you have? Stock? What does your gauge peg at?

 

[slowneasy]

stock fuel pump, gauge is Di-pricol and reads to 30psi

 

[Oil Burner]

Where are you tapped in for the reading. At the fuel filter canister since its a '99?



Did this just start or has it always been like this? Sounds like maybe a bad gauge at this point.

 

[slowneasy]

the first time I noticed it was one time back in Sept. when I was up in the mountains and one morning the temperature was in the low 30's. Now, it's done it several times whenever it's below 40.

It could be the gauge but it does read steady and the needle doesn't bounce around. Idle has always been right at 13-14. 5 psi and even though I never bury me foot in it, I've never seen anything below 11. 5-12 psi. (this is with a fully loaded truck, work body, no trailer going up grades).

I'm tapped into the top of the fuel canister and plumbed with stainless steel braided fuel line into the cab with a safety needle valve that's mostly closed to eliminate gauge noise.

 

[Tinman]

I have had exactly the same phenomena on a few cold mornings (<30*) this year. I have an Isspro mechanical gauge without an isolator (yes, a fuel line runs into the dash). I have the gauge line coming from the FASS port and have a gate valve in line (just in case something leaks inside). I keep the valve cracked just enough to get pressure for long gauge life. It takes . 5 - 1. 0 seconds for the pressure to come up to 15psi (gotta love the FASS ) on starting. After this happened a few times I opened the valve a little and it hasn't come back. I was thinking the thicker, lower temp fuel is getting pumped pass the cracked in-line valve but not building up back up enough back pressure to the pump. Therefore, fuel gets "stuck" between the valve and gauge with a higher pressure than what the real fuel line has. I don't think I did a good job of explaining that, but I hope you see what I mean. I don't think the VP is seeing a higher pressure. Your system may have a small orifice in it like my in-line valve and cause the same thing. Try a good dose of anti-gel and see if it goes away.

 

[EGaskamp]

Ever since I put in my Isspro EV 0-30 FP gauge and Autometer isolator when it is around 55 outside the gauge takes a while to even register but ever after the engine warms up it only reads about 7 psi. Any ideas? I'm tired of these isolators! They have never worked right for me. I'm thinking about running a straight diesel line into the cab with a valve. I've never had the slightest drip so I feel pretty comfterable doing that with a valve. Thanks



Eric

 

[OL RATLR]

Ever since I put in my Isspro EV 0-30 FP gauge and Autometer isolator when it is around 55 outside the gauge takes a while to even register but ever after the engine warms up it only reads about 7 psi. Any ideas? I'm tired of these isolators! They have never worked right for me. I'm thinking about running a straight diesel line into the cab with a valve. I've never had the slightest drip so I feel pretty comfterable doing that with a valve. Thanks



Eric

Eric! I have been running a Isspro mech in cab3 yrs no leaks no problems.

 

[Rattlin_Ram]

What type of line do you run into the cab? Can you use the lil plastic line that came with my isolator?

 

[kscheffler]

Air in the line bleed it.

It sounds like air in the line. Bleed it at the system high point and see if it solves the problem. I see this with my SPA fuel guage if I vent it once every couple of months no problems.

 

[Bandit2]

I ran a 125lb. psi line into the cab for my gage. No regrates. Even if it did leak ( it won't ) it would not be much because of the needle valve under the hood.

 

[Oil Burner]

been running without an isolator on mine also. 2 years and no problems. I also sleeved the plastic line with some vacuum hose to protect it.



Jason

 

[KLockliear]

What did you use in the line on the gauge side of the isolator?

 

[highgear]

i had the same problem the fix was first put antifreeze 50/50 mix into the isolater and get as moch air out as you can then put the clear plastic line on, make sure that you dont overtighten the brass fittings if you do the barrel ring will colapse and a air leek will make the gauge read low. the brass sleeves that go onto the 1/8 clear tubing are found at ace hardware stores thay coat only . 005 cents my first attempt was to fill the isolater and the plastic 1/8 tubbing with antifreeze . that didnt do any thing other than my gauge kept climing to30 lb pressure.