New fuel pump won't run 2002 GP

[58Tate]

2002 Grand Prix 3.8. Car just would not start one morning with no previous signs of trouble. Tested for spark. Then tested for power at fuel pump and had 10 volts at turn of the key. I got a fuel pressure tester from O'reilly and determined I had no pressure. I Figured that because I could not hear the pump kick on. I bought a new Airtex pump but it came with a different 4 prong plug and harness to splice into factory connections. I noticed that I could interchange the 4 wire harness from the orig. pump and new pump instead of using the butt connectors supplied and did so, testing for continuity at each point. I installed pump and hit the key and no pumping. I tested the power coming in and still have 10 volts when trying to start. WTH!!! Can someone please help?? If I don't get any good advice I guess I will splice into the wires and try that, just don't see how that will help. P.S. I hooked up old pump to a battery on my work bench and it worked. Insult to injury.

[jerryg2112]

If your battery is fully charged and your not getting 12 volts at the pump I would check the relay and connections.

[Tech II]

When it comes to motors and solenoids, I'd rather use a test light.......attach the test light to the battery and turn the key to on....look at the brightness(can check the voltage with a voltmeter in parallel with it....fully charged battery is 12.6 volts.....

Disconnect test light .....disconnect harness to the pump.....attach test light to the fuel pump......turn key to on....should light with the SAME BRIGHTNESS for two seconds as across the battery(if you crank the vehicle, should light constantly)....if you want, put a voltmeter across the light to get exact voltage...should not be more than 0.2-0.4 volts different at harness from the battery.....if voltage is good, and harness was hooked up correctly, bad pump.....you won't be the first to get a bad one right out of the box...

[58Tate]

After plugging my used pump back with some jumper wires I found that it worked when I hit the key. Plugged back up to the new pump in tank and nothing. After a few rounds of this the new pump fired up. I guess that there must have been corrosion in one of the plug ends. I sprayed the ends with mass air flow cleaner blew out with air, repeated and then coated with a little grease. The pump works fine now. When I started this repair I had 10 volts showing on my voltmeter, [ 10 is what I read that actually runs the pump from the relay ], and I had continuity throughout the wiring, the simplest thing held me up. GO FIGURE.

[jerryg2112]

You said you have 10 volts coming from the relay. How much is going to the relay? 10 volts to run the fuel pump just doesn't sound right to me.

[58Tate]

Jerryg2112. Must be a Rush fan. When I was searching threads to see if anyone had a similar problem, I came across the 10 volt comment. My battery is fairly new and fully charged. Plus I kept a trickle charger on it while diagnosing. The car runs great. I only checked the voltage 1 time and I didn't check it after it powered either pump. Thanks for the help.