So here is the deal all the sudden I lost fuel pressure or so I think. My lift pump is a air tex put on in October. The truck has run great 20psi idling and no lower than 10psi on it hard and never a hiccup. Fast forward to yesterday my fuel pressure guage started going wacko it would bounce from 20psi to zero and hold at zero and then it would come back up and stay up and then go back down . So I am 200 miles from home and it ran like a top all the way back up here no bucks no farts no code. My mileage per gallon is in check with what it is always most seem to say your mileage goes up or down with failing pumps it ran like a dream no smoke nothing. What are the chances my guage is toast and not the new lift pump? just cant fathom that in a day the whole bottom can fall out. I have tried to tighten the snubber and that did not help the only thing maybe is the set screw backed off and is closed the guage off. If my fuel filter was plugged wouldent just stop it dead in its tracks? the fuel filter was change the same time the pump was put in.

 

Since theres no response yet - Ill take a stab.

I doubt the guage is the problem but it could be. The cheapest way to start is to get another guage and verify that you have a problem. You should be able to pick a guage up for cheap ($5-8 or so).

On a 24V its always a good idea to carry a backup guage in the truck.

 

I agree with Dr. Evil, double check fuel pressure with another gauge.

But I'm leaning towards it being your Airtex. I went through 2 of them, they lasted 2 months each. Mine would start doing the same, start throwing around different psi readings. I would be running around 5psi, give the pump (along the frame rail) a tap with a hammer and the psi would jump up to 15. After a short drive it would dive back down to 5, replaced the airtex with an airdog100 and haven't had any problems when it was on my 99 or currently on my 01.

 

Some may disagree, but if you want your lift pump issues to come to an end, just relace the lift pump with an Airdog, FASS or MITSUA...I know they are expensive but using anything else is a waste of $$ and time.

 

Well I think its fixed. I ran the truck down too pretty low fuel on friday getting to the next filler up n go station. I think what happen was I put a air bubble in my system as the "pusher" style of the air tex pushed air in and it went up my hose to my gauge and vapor locked. As of this after noon I am back too 20psi ilding and 12psi running down the road. I still like the air tex style of pumps its not the same one as the oem its more a puser style. I am saving of for the glaicer verson of the mitusa pump when the time comes.

 

Good to hear......!

 

Time with tell but I am almost positive I got a air bubble and it had too burp. Talk about a pucker factor but I am glad I think it worked because there was no signs of a failing pump no bucking no code no nothing and sides i head the pump pressurize this after noon I can't wait for the fuel boss though it will be nice

 

There is another maker of that pump - in case you didnt know.

 

There are three of them right mit rasp and glacier? i just cannot afford one of them right now and the newer version of the air tex is working for me so fur.

 

I was told from cummins that over 15lbs of pressure to the Injector pump could cause premature failure

 

I think your right but its not idle psi I think its when you got it pushed to the head lights and your still making 20psi you got a problem mine pulls to 12psi on the road and 8-10psi with a load.

 

looks like it still showing no fuel psi guess I am going too have too get another darn fuel pump.

 

Bah, sorry to hear Cowboy! I just don't find those airtex's are build well at all. Sure they supply good pressure for awhile, but not long enough IMO.

cminzey; A lot of people will say that 20psi at idle is as high as you want to go with a VP. Anything above that and it may wreck the diaphragm.

 

I like the idea behind them so I bought another and this fall when I sale my calves there will be one of the three mechanical fuel pumps more than likely the glaciers version. I have been reading the installation manual for the fuel boss and and getting more excited soon as I get the new lift pump in the fuel boss looks like its the bread winner and really straight cut to install.

 

I love my truck again 20psi idling solid no flutters and no dipping and a personal best of 20min lift pump changed this time was much easier for the air tex because all the re fit stuff I had to do the first time was not needed. Best of all she primed and fired on the first pull