2003 Yukon won’t accelerate past 3,000rpm and chokes/sputters

[Rshann5355]

Yeah 50 Psi and all the bleed off aint gonna cut it. Id expect atleast 55-60 PSI with almost no leak down.

What are you thinking is the issue?

 

[rockola1971]

What are you thinking is the issue?

Im thinking you have multiple issues. I would have a look at the fuel trims. Are you running rich? Possibly leak injector(s) but I would think you would see that at idle. So if nothing shows no evidence of running rich then I would honestly suspect the fuel pump as a culprit. Yours will have a check valve in it and if that check valve isnt working then that would explain the bleed down of pressure happening.
Sounds like the fuel filter probably has been on there a long time and needed to be replaced like most do. When it comes to the point that the tank has to be dropped then I would inspect the tank for dirt and crud and clean out accordingly. I would NOT waste my time with an aftermarket fuel pump either. Delphi, Delco or Bosch.
A Tech II really comes in handy for this kinda mess. I own (2) 2003 Tahoe LT's Vin Z and a Clone Tech II and I cant say enough how much of a lifesaver the Tech II is.

 

[nonickatall]

Hey all,

I’m having an issue on my 2003 Yukon that seems to be fuel related. The truck had all the seals redone in the motor not too long ago, holds great oil pressure and runs smooth, but I’m unable to accelerate past maybe 1/4 throttle. The truck will sputter and back fire, and it gets worse the lower the fuel gauge gets. I’m also unable to fill the truck all the way, it’s been filling up on 17 gallons at most. Any ideas?

First I would remove the vacuum hose from the fuel pressure regulator. If fuel comes out, your fuel pressure regulator is brocken.

That explain the high fuel consumption and bad engine running.

 

[Fless]

First I would remove the vacuum hose from the fuel pressure regulator. If fuel comes out, your fuel pressure regulator is brocken.

That explain the high fuel consumption and bad engine running.

He said the vacuum line to the FPR hasn't been connected since some work was done.

 

[nonickatall]

He said the vacuum line to the FPR hasn't been connected since some work was done.

I didn't read with enough attention, i guess..

 

[Rshann5355]

Im thinking you have multiple issues. I would have a look at the fuel trims. Are you running rich? Possibly leak injector(s) but I would think you would see that at idle. So if nothing shows no evidence of running rich then I would honestly suspect the fuel pump as a culprit. Yours will have a check valve in it and if that check valve isnt working then that would explain the bleed down of pressure happening.
Sounds like the fuel filter probably has been on there a long time and needed to be replaced like most do. When it comes to the point that the tank has to be dropped then I would inspect the tank for dirt and crud and clean out accordingly. I would NOT waste my time with an aftermarket fuel pump either. Delphi, Delco or Bosch.
A Tech II really comes in handy for this kinda mess. I own (2) 2003 Tahoe LT's Vin Z and a Clone Tech II and I cant say enough how much of a lifesaver the Tech II is.

I’m thinking it’s going to be the check valve as well, so the pump will definitely be coming next as well as cleaning off the tank itself with all the mud. I’ve got a decent scanner I use on both of my Mercedes. I can’t believe that A Tech scanner is more than a STAR diagnostic for the Merc.

 

[nonickatall]

I’m thinking it’s going to be the check valve as well, so the pump will definitely be coming next as well as cleaning off the tank itself with all the mud. I’ve got a decent scanner I use on both of my Mercedes. I can’t believe that A Tech scanner is more than a STAR diagnostic for the Merc.

I think you first should make clear that enough fuel is coming to the injection system. So first i would change the fuel filter, if you not did that allready. I would as well check if any of the fuel lines are squeezed from any collision. Than I would exchange the fuel pressure regulator. This part is very cheap, but absolute relevant to a good running engine. To clean the tank is good, to prevent the fuel filter from dirt as well.
A fuel pump from my experience, works or not. It is rather rare, that a fuel pump loses power. And if, you can measure a weak fuel pressure.

As well I would check for air leaks in the intake system.

 

[Rshann5355]

I think you first should make clear that enough fuel is coming to the injection system. So first i would change the fuel filter, if you not did that allready. I would as well check if any of the fuel lines are squeezed from any collision. Than I would exchange the fuel pressure regulator. This part is very cheap, but absolute relevant to a good running engine. To clean the tank is good, to prevent the fuel filter from dirt as well.
A fuel pump from my experience, works or not. It is rather rare, that a fuel pump loses power. And if, you can measure a weak fuel pressure.

As well I would check for air leaks in the intake system.

The fuel pressure regulator is brand new, was replaced before I got the truck. I just replaced the fuel filter last night as well, and removed the vapor canister.

 

[Rocket Man]

Following

 

[Rshann5355]

Truck is back to running poorly when going down the road, I now have a Delphi fuel pump on the way and will be installing this weekend. If that doesn't work I'll move on to injectors, which are doubtful, but if that is the case it'll be a bit before I buy all of them. Thanks for everyone's help so far, definitely the best forum I've been a part of.