1995 Chevy Blazer fuel pump relay switch

Tiny
HAWKEYE0286
  • MEMBER
  • 1995 CHEVROLET BLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 89,000 MILES
Our Blazer is having trouble starting and we can hear the fuel pump coming on when we try to start it. Someone told us that it is the fuel pump relay switch, that is located under the hood and with other rerlays. Where would we find the fuel pump relay switch? Thanks.
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Monday, October 27th, 2008 AT 10:32 AM

4 Replies

Tiny
SWILLIAMS
  • MEMBER
If your hearing the pump turn on when you turn on the key the relay is OK. What does it actually do when you're trying to start it?
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Monday, October 27th, 2008 AT 1:23 PM
Tiny
HAWKEYE0286
  • MEMBER
When we try to start the Blazer, it acts like it isn't getting fuel. That is why we tried the fuel pump relay switch. Thanks
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Monday, October 27th, 2008 AT 7:26 PM
Tiny
CARPROBLEMS1996
  • MEMBER
Seems we have the same problem with blazers. My daughters is doing the same thing. We used some carb/choke cleaner sprayed into the air intake and it cranks fine. Runs great once it is cranked. Just doesn't get fuel to crank. I am still trying to find out what to do with ours. I wish you luck and if I find out anything, I will let you know.
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Wednesday, October 29th, 2008 AT 9:57 AM
Tiny
SWILLIAMS
  • MEMBER
Ok in the case of Hawkeye I would run a pressure check on the fuel pump. Make sure your getting 55-60 PSI at the test port. Then test for flow rate. You should be able to pump about 2 pints of gas out of the test port in less than 20 seconds. That will show you if you have the proper fuel delivery to the injectors. Now test the regulator and injectors for leakage. To do that watch the pressure gauge one you turn off the key. The pressure should stay at the same level for at least a minute. If it isn't then you have a leak, and will need some additional testing to see what you have.

To Carproblems: Since the problem your seeing occurs only while starting the problem is likely the fuel pump relay. The system works in a unique way.
The first step is you turn on the key, this tells the computer to activate the FP relay. The relay turns on for 2 seconds to build pressure in the system while the engine cranks over. Once the engine cranks a bit and starts to run and build oil pressure a different switch turns on and that circuit powers the pump.

In your case the relay isn't working. It could be a bad relay or bad connection at the relay. Or a problem with the switching circuit in the ECM.
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Wednesday, October 29th, 2008 AT 1:53 PM

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