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j_ramsey
j_ramsey, ASE Certified Technician
Category: Chevy
Satisfied Customers: 972
Experience:  ASE certified engine repair a/c automatic transmission steering and suspension
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1998 chevy tahoe: fuel pressure..the throttle body..pressure regulator

Customer Question

1998 chevy tahoe 5.7. 60 psi fuel pressure vehicle will not start until you pour fuel in the throttle body and then it will start and run until you shut it off. Change dfuel pressure regulator 3 times. Came in for a cold start problem and then quit al together. can you help
Submitted: 9 years ago.
Category: Chevy
Expert:  j_ramsey replied 9 years ago.
Your fuel pressure is in specs and you obviously have injector pulse if it will run when fuel is poured through the throttle body. Have you checked all of the ignition system- cap -rotor and spark plugs ? That vortec is very sensitive to plug wear and proper plug gap. It could also be that they added the wrong fuel or got bad fuel. I would also take a fuel sample in a jar and let it sit to see if there is any fuel seperation -meaning that there is water or something else in the fuel . Were any codes set in the computer ?
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Customer: replied 9 years ago.
There were no codes in the computer. Changed crank sensor, pick up coil and ignition module made no difference. have been told \vortec needs 62 to 66 psi to start and will run on less even change oil pressure switch. is it possible the fuel pump does not supply enough pressure. I am not sure if my fuel pressure tester is accurate.
Expert:  j_ramsey replied 9 years ago.
I read earlier that fuel pressure specs are 60 to 66 psi. It couldn't hurt to try another fuel pressure gauge if you have one or know someone else that does. I was thinking that there may be something with the fuel itself since it will run once you pour fuel into the throttle,it's like there is not enough octane in what is in the tank.
Customer: replied 9 years ago.
If it had bad fuel wouldn't it run rough after i started it.
Expert:  j_ramsey replied 9 years ago.
No,it will run on bad fuel. Sort of like someone putting diesel in a gas vehicle,it will run ,but once it is shut off it will not start on it.
Customer: replied 9 years ago.
current fuel pressure reading after cycling key one time is 56psi I just ordered a new pressure guage. If pressure reading go up I drain fuel if not I drain fuel when I change the pump. and let you know what happens
Expert:  j_ramsey replied 9 years ago.
Yes,56 psi would be just enough to keep it from starting. Has the fuel filter been checked or replaced ?
Customer: replied 9 years ago.
no I will check it
Expert:  j_ramsey replied 9 years ago.
Hopefully that is your problem, otherwise if the last pressure reading was correct it's a fuel pump problem.
Customer: replied 9 years ago.
changed the fuel filter and pressure actually went down
Expert:  j_ramsey replied 9 years ago.
Was the filter clogged ? Sounds like it did damage the fuel pump.
Customer: replied 9 years ago.
Changed fuel pump and starts and runs great thanks for your help