Engine Sur-Sur-Surging

Coasterman

Coasterman

coastn'
Joined
Aug 27, 2009
Messages
25
Ok this is odd...my truck has 253k on it, a rebuilt pump and factory mopar trans replace a few months back.... This is my problem, driving with no load, at speed (60-75), crest a hill or on a slight decline and the truck acts as if its starving for fuel. EGT post turbo stays around 6, trans temp is normal... Any ideas were to start would be great. :banghead:
 
Fuel pressure? If you have nothing but the stock lift pump that is the first place I would look.
 
Does it do it repeatedly? Or just once, every once in a while?

If it's a repeated problem, I would check the lift pump first like Billy said. Also, the fuel filter. (VP trucks are stupid weird) If it happens once, every once in a while, I'll let you know when I figure out what causes that, it's in the wiring, and I still can't find it.
 
Billysgoat said:
Fuel pressure? If you have nothing but the stock lift pump that is the first place I would look.
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ok, i'll start there..is this just a swap out and see or is there any way to test the lift pump? no big deal to pull it out...just didnt know if there is a way to test it..
 
crewgirl said:
Does it do it repeatedly? Or just once, every once in a while?

If it's a repeated problem, I would check the lift pump first like Billy said. Also, the fuel filter. (VP trucks are stupid weird) If it happens once, every once in a while, I'll let you know when I figure out what causes that, it's in the wiring, and I still can't find it.
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repeatedly... thought it was my tranny at first,,and i was more than a little relieved when both you and bill said lift pump...same question though is there a way to test the lift pump?
 
You can pull it off and put it on a battery to see if it runs. But probably the best thing to do is just get a new one, or a Holley Blue pump (the red doesn't push enough gph for our trucks), and swap em out. I've had lift pumps that went to weak to push enough fuel to my vp, that would still pump fuel out of a 5 gallon can.

BTW, my truck used to eat lift pumps on a regular basis. I have a Dr. Performance one now that's holding its own.
 
had a friend that recommended an airdog...i dont know if its worth the money.. i will check out dr performance
 
I got the Dr. Performance cuz of who I know, but, if I were gonna spend the money, I'd go with an Airdog.
 
You can bump the starter without starting the truck and you should be able to hear the lift pump running for about 10 sec then stop. Do not assume just because its running that your fuel pressure is good. You need to check it at the pump with a mechanical fuel pressure gauge. If your fuel pressure is low and your injection pump is still good it wont be for long.
 
smoken02 said:
You can bump the starter without starting the truck and you should be able to hear the lift pump running for about 10 sec then stop. Do not assume just because its running that your fuel pressure is good. You need to check it at the pump with a mechanical fuel pressure gauge. If your fuel pressure is low and your injection pump is still good it wont be for long.
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thanks smoken, will try that this morn...i'm also gonna check with a local shop today to get my fuel pressure checked.
 
It's hard to check the fuel pressure, unless you have an in cab gauge. The problem occurs while driving. Also, I tried to say it before, but I wasn't real clear (I blame cold meds), a lift pump can still work well enough to pump fuel, but can be too weak to pump enough to the vp. A vp is cooled by fuel, if it's not getting enough fuel, bad things are happening to it.
 
ok crewgirl makes sense... everything else checked out today just no pressure gauge yet....talked to blue chip performance..they think its a vp thats just plain worn out. I like your idea a little better mainly cause it will cost me less if your right! thanks for the info! gonna order up a good fuel pump this coming week, airdog prob. oh and driving with a two horse steel trailer today the truck ran like a top! what the heck :bang ah well still gonna get an airdog. Now i just gotta sell all these parts i got lying around!!
 
I just went through this whole deal with my buddies truck. He just bought an 02 dodge. He called me and said when he got on the interstate the truck would cut out bad. Once he let off the throttle and then got back into it things were fine. It only did this once in a while. He didnt have a fuel pressure gauge in his truck, so i took my mechanical fp gauge and hooked it up to the ip to see what it had. 5psi at idle is all it had. This is not enough fuel at idle. 5psi is already lower than I would ever let the fuel pressure drop too. At highway speeds there is no way that truck had any fuel pressure at all. The injection pump only lasted a couple days even after we put the airdog on it. Even if you dont have an in cab gauge I would still check it at idle under the hood. If your fuel pressure at idle is low then there is no sense in driving it. You will only hurt your injection pump worse than you already have.
 
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