Engine/Transmission (1998.5 - 2002) varying fuel pressure problem ????'s

[johncameron]

Hi, Last year I got a new LP installed under warrenty after I installed my Westach PF guage. In the last few weeks I've had a strange problem with my pressure after driving for over 30 mins on the highway. I'm getting a normal 13-15 lbs at cruise for the first 30 mins or so but after 30 mins or so it will drop to 4-6 lbs. At first I thought it was my guage so I borrowed a mechanical guage from my dealership (yes... no charge!!!!) and it did the same thing to me with theirs. Does anyone have any idea what may be causing this problem? If I shut the truck off when the pressure is low it will go back up to 14ish and then go right back to 5ish after I restart. Also, when the pressure is low, if i floor it the pressuer will rise???? back up to 8 lbs. That is the normal WOT pressure for my setup. I'm kinda stumped with this one. I still have 3K miles on my warrenty and my stealership will cover me if it is a mechanical or electrical problem. If the fuel lines or screen in the tank is blocked,I'm not covered.



Thanks in advance!



John

 

[AKAMAC]

Have you tried changing the filter?

 

[johncameron]

I havn't changed the filter in 10000miles but I was told that the exit on the side of the filter housing was pre-filter? Is that true? I am due for a change though.

 

[azpete]

My original pump did the same thing at around 45000 miles. Ever once in awhile would go down to 5 psi and if I accelerated the pressure would go back to the normal 14 or 15. Put a new lift pump in and the problem went away.

 

[Slightly Modified]

I have been through three lift pumps in the last year and that is exactly the symptoms all three were showing when they were on their way out. I would get the dealer to put a new lift pump. The one I am on now is the only one that has made it past 5,000 miles. Get it free while you can.

 

[rwitt]

Hi, Last year I got a new LP installed under warrenty after I installed my Westach PF guage. In the last few weeks I've had a strange problem with my pressure after driving for over 30 mins on the highway. I'm getting a normal 13-15 lbs at cruise for the first 30 mins or so but after 30 mins or so it will drop to 4-6 lbs. At first I thought it was my guage so I borrowed a mechanical guage from my dealership (yes... no charge!!!!) and it did the same thing to me with theirs. Does anyone have any idea what may be causing this problem? If I shut the truck off when the pressure is low it will go back up to 14ish and then go right back to 5ish after I restart. Also, when the pressure is low, if i floor it the pressuer will rise???? back up to 8 lbs. That is the normal WOT pressure for my setup. I'm kinda stumped with this one. I still have 3K miles on my warrenty and my stealership will cover me if it is a mechanical or electrical problem. If the fuel lines or screen in the tank is blocked,I'm not covered.



Thanks in advance!



John

Mine is doing exactly the same thing. I've changed the filter and still the same problem. Took it to the dealer and it passes the flow test( 50 to 52 ounces) but the pressure was most likely good when it was done. The first lift pump that went out took out the VP44 so you'd think the dealer would want to replace this one before it happens again. At this point I'm waiting for it to completely die so that it will be replaced under warranty.

Rich

 

[johncameron]

New LP installed under warrenty today, no question asked! They had to charge me for . 10HRS install which was a grand total of 6. 80$. I won't complain over that. Thanks for your replies



John

 

[HOSSBOBCAT]

JOHN IF YOU WANT TO SOLVE ALL YOUR PROBLEMS WITH FUEL PRESURE YOU NEED TO INSTALL A F A S S SYSTEM i JUST DID AND IT IS AWSOME PERRS ALL THE TIME.

 

[johncameron]

my next system after my warrenty is up will be a FASS or equal. It was still almost free at the stealership so I went with a stocker!

JC

 

[Warpig]

JOHN IF YOU WANT TO SOLVE ALL YOUR PROBLEMS WITH FUEL PRESURE YOU NEED TO INSTALL A F A S S SYSTEM i JUST DID AND IT IS AWSOME PERRS ALL THE TIME.

I second that!!!!! No more lift pump, VP44 well fed and happy.



Tim W.

 

[Sticks]

Instant repair procedure #3... Whack it with something.



I have had the same problem on two pumps, and my uneducated but experienced opinion is either the pressure/regulator ball in the pump gets stuck, or one of the four vanes on the impeller gets stuck. Whacking it with a wrench or something (READ - firm tap, not a deep center field drive) cured the problem.



Might also try taking the top of the pump off (3 studs) and clean the impeller assembly and check for burs.



NOTE - I used to be one of the "It's a perfectly good pump, just in the wrong location" guys, but now I must say that the OEM Carter LP is a POS pump that is designed to fail frequently. I am not about to spend $400 on another replacement LP package. Have been informed by someone high up in the industry that the next step up is an Airtex brand pump that is put on medium duty diesel applications. I have yet to source one due to lack of resources but the search continues.