Engine/Transmission (1998.5 - 2002) Fule pressure

[TBrock]

I have a 2001 with 100k mi last winter I replaced the lift pump and the injection pump put in bigger injectors and put a fuel pressure gage in, after I installed the pressure gage I had a problem with the pressure jumping all over the place it would stay around 10psi at idle but would jump 3 or 4 psi up and down as fast as the needle would go. I figured it was air in the line, last week I replaced my fuel filter when I fired it up the gage was rock steady at 11psi. It stayed that way for 2 days then started jumping again. I pulled out the filter thinking mabe it was clogged but looked like it did when I put in in so I put it back in fired it up and it was rock steady again stayed that way for 2 days then started jumping again???



any ideas Im stumped

Thanks Thomas

 

[SnoKing]

Is this an electrical or mechanical fuel pressure gauge? If mechanical are you running an isolator? SNOKING

 

[TBrock]

Its electrical.

 

[SnoKing]

Sounds like a bad sender. SNOKING

 

[MeritBadge]

When your changing the filter your also removing some fuel and adding some air. The air is acting like a snubber and gives you a more constant pressure reading. After a short time the air is worked out of the system and you're beggining to get a true pressure reading. Many stock lift pumps have erractic pressures.

 

[blacksheepdiesel]

It could be the source of your electrical power for the gauge, try hooking to a different circuit, preferably one by itself.

Godspeed,
Trent

 

[Jed]

Unfortuately, many people have traced their fuel pressure problems to a bad isolator or sending unit. FASS got a panic call from me when my pressue suddenly dropped to 0 (bad isolater)

 

[BWagnaar]

I have a mechanical gauge in mine and after it worked fine for about 6 months but than started doing what you described. Mine would rattle really loud the longer i left it in there... Pretty much the gauge was blown. Luckily Summit has a great return policy, but it took 4 gauges before someone pointed out that i had ran my line to the banjo bolt on injector pump and that it was getting pressure spikes which was destroying the gauge. I guess the better way is to tap into the line from the filter to the inj pump at the filter as possible ( less or no pressure spikes).
I dont know if this helps you with an electric gauge, but if you have the sender at the inj pump it could be getting pressure spikes... . good luck.