Question about 1996 GMC Sierra
Fuel pump died replaced it truck ran poorly afterwards. Had a prussuer test done pump determend pump was no good. Put in another ran good for 2 days started running poorly hard to start no power. 2nd fuel pump. So i figure another bad new fuel pump wow changed it put in a third brand new fuel pump. Still will not eve start now. I had it tuned up 2 months ago new plugs rotor, cap, etc. put in a new fuel filter made sure it is on proper checked all connections for leaks. this cannot be a fuel pump problem now. no problem with the elctrical i figure i have great spark on ignition tester. I can hear the fuel pump prime when i turn the key. but when i went and checked the fuel port i had no pressure. When it is being cranked gas sews out of the test port. Also i dont if this is comon cause i used to turn my keyand go. but when i have someone turn the key and i listen at the gas tank whn the key is shut off i hear gs spraying back into the gas tank. So i am open for opinions.
gmc 2500 5.7 with sfi occasionally hard to start has to turn over 2-3 times
fuel preasure good but falls when engine cut off
replaced sfi with mfi new fuel filter checked 2 plugs clean and firing
Hey there boatright33,
A few things things immediately come to mind.
There may be a problem with the engine controller. You could check the ODBII onboard diagnostics. Auto part stores will usually do this for you at no cost.
When you pulled the ones that were/went bad, how did the filters look? Could there be particulate matter still in the tank causing them to fail.
I always put this one off until last. Check the injectors. Are they gummed up?
Let me know what you find out
Posted on Aug 12, 2008
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