99 tahoe with 5.7 won’t stay running!

[ANder]

Hey all. I have a 99 tahoe with the 5.7l motor. Just replaced fuel pump and filter. It will start after cycling the key a few times. It will rev in park and neutral as high as I can get it. If I put it in gear and give it gas it will run, and idle. If I try to just roll in forward or reverse it dies and I need to cycle key a few times to get it running again. The fuel pressure at the rail was about 40 psi before I changed the pump and filter. Have not tested since change. Anyone ever deal with this issue? Any thoughts are much appreciated.

 

[OR VietVet]

Check the pressure, that is basics. If you can, attach with long enough hose to watch what the pressure does when it is running and you go thru the same steps as before. What brand pump? Why was it replaced to begin with? When I look at application in RA I see a 2 door and a 4 door version. Which one?

 

[ANder]

Thanks for reply. It’s a four door. 5.7l with 4l60 trans. The pump is a Delphi. I brought it to a shop to get diagnosed. They told me it was the pump. Changed it myself at home. No go. Thanks.

 

[ANder]

Thanks for reply. It’s a four door. 5.7l with 4l60 trans. The pump is a Delphi. I brought it to a shop to get diagnosed. They told me it was the pump. Changed it myself at home. No go. Thanks.

Also when I cycle the key the pressure gets up in the 50’s and pretty much stays there. First turn of the key it hits 40 and stays there.

 

[Fless]

Is there a fuel filter on it and, if so, has it been changed recently?

 

[ANder]

Is there a fuel filter on it and, if so, has it been changed recently?

Yes. Brand new filter today. Thanks for the reply!

 

[OR VietVet]

Ok, I will ask it again, what is the part # for the pump you go from Delphi? FG0089 is the 4 door version at RA.

Plus, I am assuming you cannot watch the pressure while driving?

Sorry, but if I ask the question, I want to get some type of answer.

You said you had it at a shop and was diagnosed, for what? Is the problem now the same problem you took it to the tech for?

 

[exp500]

Any codes ? Have you swapped fuel pump relay? You can diagnose/fix 95 percent of problems with a bluetooth scanner, Spark tester, fuel pressure guage and multmeter. More than a sentance in your request will usually get a reasonable response.

 

[OR VietVet]

Your problem may be related to this part: https://www.rockauto.com/en/moreinfo.php?pk=88851&cc=1353721&pt=6072&jsn=959, Idle Air Control Valve.

That valve adjusts at the throttle body, for the air/fuel mixture, when it senses a load on the system, such as accel from stop or turn a/c on....etc. The passage where it threads in to tends to build up carbon and crud and does not allow the IAC to do it's job. In that case it would require an attempt to clean it or replace the throttle body.

Not saying this is the problem but am saying it could factor in.

 

[ANder]

FG0089 is the Delphi part number. No codes. Will check fuel pressure while running tomorrow evening. I have not swapped relay. Thanks for giving me a couple things to think about. It won’t stay running in order to check pressure while driving. Brought it to the shop because it would not start and had low fuel pressure. Was sitting in the road where I couldn’t work on it. The tech said it was the fuel pump that needed replacing. Sorry if I’m not being thorough enough. I know my way around a vehicle but not a pro mechanic.