Page updated on 06-22-2018

95 Bonneville Fuel pump problems or ???

08-04-2004, 04:16 PM
Have a 95 Bonneville SE (3.8 LTR) with approx 163,000 miles on it. The fuel pump died about 11 months ago and I replaced it with an ACDelco OEM pump. Last Friday it looked like the pump went out. I listened to the tank with a stethoscope and could not hear the pump and when I checked to see if I was getting voltage I was getting 8.3 volts at the connector to the pump. I was not sure which of the 4 wires on the harness were to power the pump so I had someone cycle through (ignition on. check. ignition off, go to the next pin, etc.) while I checked for voltage. I dropped the tank and replaced the pump and 3 days later.. My wife called me to let me know the car "died".. She stated it just started to "bog" down then stopped running and it acts just like it did before.. Cranks but no fire....

My questions are:

1) Could it be the fuel pump relay? Where is it and how to I check it? (I looked in the manual I bought from the auto parts store and it does not show where or how to check).

2) What should the voltage be on the connector to the tank? How do I determine which of the 4 is for the pump? (I understand the pump should run for approx. 15 sec to pressurize).

3) What's the likelihood I would get two bad ACDELCO (brand new) pumps in a row? What else should I be looking at???

Thanks in advance for your help!

08-04-2004, 10:59 PM
well that is very strange I dont think that two fuel pumps could go out like that you might be on the right track with the fuel pump relay
the only other thing that I could think of is check the fuel line in the tank make sure there are no hole in there at all the best way to do this is take them off and blow in the other end and make sure there is no air getting out I have had the same problem in the past and all it was A small tiny hole in the line
Please get back to me and let me know how it goes

08-05-2004, 08:25 AM
Thanks for the suggestion I will check the fuel lines.. Anyone know where the fuel pump relay is located on a 95 Bonneville? Can it be bypassed or any way to test it?

08-05-2004, 03:31 PM
I answered your other post and now know why you want to bypass the relay. Your Chiltons should describe a test pin for the fuel pump behind the battery. It looks like an insulated female connector that is supposed to be connected to something but is not. On my 93, the wire coming out of the connector is red. If you apply +12v to this connector, it should activate the pump.

Any relay can be tested with a continuity tester by applying +12v to pin 86 and ground to pin 85. There should be continuity between pins 87 & 30 when connected this way. If you disconnect either pin 85 or 86 there should be continuity between pins 87a and 30.

08-06-2004, 10:46 AM
Thanks for the info! I'll let you know how I make out!

09-16-2004, 12:45 PM
Thanks for all the assistance, I am now (after two hurricanes) able to get back on the internet! Turns out it was a bad fuel pump and a cracked fuel line. I think that cracked link caused the pump to fail...

Add your comment to this topic!