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Jerry Newton
Jerry Newton, Chevy Technician
Category: Chevy
Satisfied Customers: 4829
Experience:  ASE Master Technician, L1, Master GM Technician. Over 20 years of bumper to bumper GM experience.
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I have a 89 chevy 1500 pick up 5.7 ltr throttle body

Customer Question

i have a 89 chevy 1500 pick up 5.7 ltr throttle body injection starts right up when cold after running it will still start right up however if left to sit for 20 minutes after running it will not start.add a little gas and it will start or waiting untill it cools and will start up. replaced fuel pump, distributor and pretty much every sensor no change. any suggestions Thanks Rick
Submitted: 1 year ago.
Category: Chevy
Expert:  Jerry Newton replied 1 year ago.

What does it NOT have when it won't start? You should be testing for spark and looking to see if the injectors are spraying fuel while someone cranks the engine.

Customer: replied 1 year ago.
It has spark it does not seem to get enough fuel to start however if you pour a little fuel in it will start. after it starts it runs fine again this only happens when it has sat 20 minutes or so after running at temp. It starts right up when cold
Expert:  Jerry Newton replied 1 year ago.

Have you checked the fuel pressure with a gauge? It's hard to connect a gauge to these, it requires a special setup that allows you to install the gauge inline so the engine can still run with the gauge attached.

Spec is 9-13 psi, it sounds like you have low fuel pressure, based on your symptom.

Expert:  Jerry Newton replied 1 year ago.

I realize you put a fuel pump in it; however, I'd still want to test that fuel pressure to eliminate it as a cause. Fuel pressure testers can be borrowed at no charge from many parts stores.

Customer: replied 1 year ago.
I would think fuel pressure would be the same cold or hot since the pump is in the tank again it runs great and starts right up unless it sits after warming up. I am working on a tester it will take a few days I'll get back to you with results thanks rick
Expert:  Jerry Newton replied 1 year ago.

I understand your logic. However, you say that if you add some fuel to it, it starts up. That suggests that this is purely a fuel issue, no?

Customer: replied 1 year ago.
Fuel pressure is good,after looking at the wiring diagram I realized that the oil pressure switch is wired with the fuel pump this is a safety cut off in case of an accident or low oil pressure it turns the pump off. It was faulty and not sensing oil pressure when the oil was hot. Problem solved