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mrfixitrick, Mechanic
Category: Car
Satisfied Customers: 143
Experience:  Over 35 years of full-time, hands-on, automotive repairs to all makes.
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my 94 Jimmy..We Checked the fuel pump presure and it was 0...replacing

Customer Question

I can't get my 94 Jimmy to start. We Checked the fuel pump presure and it was 0. We replaced the fuel pump fues. what else can we check to make sure it is the fuel pump before we spend all that money and time replacing the pump. Any tips on replacing the pump.
Submitted: 8 years ago.
Category: Car
Expert:  mrfixitrick replied 8 years ago.
HiCustomerand welcome to JustAnswer.

My name is XXXXX XXXXX I will help you diagnose the possible pump problem.

Listen to the fuel tank area carefully when the engine is being cranked...can you hear a fuel pump whirring sound?

Try doing a voltage check at the rear fuel pump wiring connector, It should show 12 volts or better for a few seconds when the key is turned to "on" position or "start".
If you have 12 volts at the wiring connector at or near the pump, the pump is likely bad.
If you don' t have 12 volts there, you need to find out why. There are some other relays and fuses that might be defective. Get back to me for more diagnosis if that is the case,

Try reconnecting the pump wire and giving the fuel tank a few light thumps with a blunt instrument; it helps to have a helper turning the ignition key on and off while you try this. Often this technique will temporarily "jump start" a bad fuel pump in order to move a dead vehicle. Then you know to replace it!

Try these tests and let me know!
Customer: replied 8 years ago.
Is the fuel pump in the gas tank. How can I get to the cinection to check for 12 v.
Expert:  mrfixitrick replied 8 years ago.
Is this a 4.3 litre engine? If so, the fuel pump is in the fuel tank. The pump electrical connection should be available visibly near the top of the tank. You may need to partially lower the tank to get at it. Here's a picture of a typical fuel pump for 1994 GMC Jimmy...notice the long connection lead and connector on the pump wire. <a href="" target="_blank"></a>
The connector will have a little tab to unlock itself.

If the fuel pump has to be replaced, the tank must be dropped, and should be flushed and clean for the new pump install. A new sock comes with some pumps, with others you get it separately.

There is a complete procedure to properly check fuel pump pressure, including how to bypass electrical to direct power to the pump using the drivers side test connector that has with a single red wire. The procedure is available from the above link, at bottom of page, click on "Repair Information for..." It should take you to fuel pump diagnosis and install page., however this page did not always load ok for me...
Check it over; this is the info you need to try first!

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