Fuel Pump or Relay

DavidH · 10-23-2002, 06:11 AM

Got in the car today after doing the headlight relay and H4 upgrade and she won't fire. Cranks fine but won't hit.
I did notice that the fuel pump which I always used to hear hum upon turning the key to the on positon is not humming. I pulled the relay and put it back in and checked fuses but still nothing. What do you think? Has the fuel pump finally bit the dust or should I buy a new relay and try this first?
This relay is the red one and I assume it is different that the others but I am going to check out the numbers when I get time tonight to really dig into this.

makaio · 10-23-2002, 06:27 AM

Take the fuel pump relay and put it in the horn relay socket. If the horn works, the relay is good.

A spare relay should be carried in your car at all times. Just in case.

Rick Lee · Rick Lee's Garage

Not sure how your engine management is set up since you have a 3.2 conversion. But if you have a DME brain, I think the fuel pump relay is inside the DME relay. Always replace that first to start troubleshooting. Then take a thick wire and straight-line it from the top of the fuel pump fuse terminal to the bottom of the hazard light fuse terminal (always on). If you hear the fuel pump whir to life, it's still good. If it doesn't, or it coughs or the wire gets hot and orange, then your fuel pump is fried.

Early_S_Man · 10-23-2002, 07:27 AM

David,

Does your car have the factory alarm system? If so, is it operating normally?

A failure of the factory alarm module can disable the fuel pump circuit, and PREVENT STARTING!

Chuck Moreland · 10-23-2002, 08:01 AM

Before you spend any money, put a volt meter on the pump terminals and see if you have power. Shot gunning is expensive, isolate the problem.

DavidH · 10-24-2002, 05:55 PM

Thanks All,
Richard no DME on this one. The fuel pump relay is the red one in the first position in the fuse box. I am getting a new one in the am so that should be ruled out soon. I stayed with the original 78 CIS setup, just bigger P's & C's with a 964 cam grind.

Warren,The factory alarm has been gone for a year now. The only other big change that comes to mind is I routed the wiring for the H4 & relay conversion behind the fuse panel and may have disturbed another wire somehow. I will check this tomorrow as well.

Chuck, I do have a voltmeter and since the skid pan is removed (Haven't put it back yet after the turbo tie rods and bump steer kiit install - Was going on after alignment next week) I can check this easiy tonight. Thanks.

Hope to have good news to report tomorrow. But I sure would like it to be that little red relay.

Thanks again

makaio · 10-24-2002, 07:41 PM

Do you have a horn relay? If so, like I stated before, you can test your fuel pump relay by inserting it into the horn relay socket. It takes all of 1 minute.

Ove · 10-25-2002, 01:16 AM

David,
Have you checked the fuse?
Read my post here:

Fuel Pump Relay

Hope this helps

hobieboy · 10-25-2002, 05:50 AM

Just a thought...
Had a similar problem a few weeks back. Turns out that the wire on mine was completely corroded at the fues panel... worth checking

DavidH · 10-25-2002, 05:50 PM

Success,
Cleaned the fuse holder, tightened the lug on the fuse block, pulled the relay and spread all the pins slightly, reinstalled and whammo. I even have a new spare relay which I know will come in handy some day.

Thanks to all for the suggestions, the hum is back...