No power to fuel pump, seems to be a common problem around here Options

[warrenoliver]

Car stalled on me this morning. When I tried to restart, the fuel pump would not turn on so no luck with the start. Towed it home and checked it out. It is a 73 2.0 with FI.

The pump runs when I jumper directly to the battery. I have continuity from pump connector to the #13 pin on the relay board. If I jumper from the fuse to the #13 pin, the pump comes on. The fuse is good.

I have replaced the main power relay and the fuel pump relay with known good ones. With the ignition on, when I remove and reseat the main power relay, I can feel the relay click but I do not hear the injectors click nor do I hear the fuel pump start (I got this test from Dr. 914's Tech Tips).

On the fuel pump relay socket, I have power at the 30 pin and also the 85 pin. When I jumper to the 87, it does not turn on the fuel pump.

I don't know if it is related, but I have the same problem with the heater blower relay also. I jumpered 30 to 87 and I do not have power. I am not sure but I think the car died when I had the heater blower running.

I'm stumped. What do I check next?

[warrenoliver]

Tom,

Aha! I think you may be on to it. Even though i have 12V to the 30 socket of the fuel pump relay, perhaps the fuse holder is not connected well enough on the left side or the trace is broken from that point giving me 12V but not enought power to run the pump. I think I will check resistance from the left fuse holder to the 30 socket for fuel pump relay. If it is loose, the resistance should change when I wiggle it and that will tell me if the rivet is loose. If not, it may be that trace. I can check that by running a jumper wire from the fuse to a small wire that i can put around the 30 pin of the fuel pump relay and then plug it in. If it works from that jumper, I think that will tell me if I have a bad relay board.
I am busy for the afternoon and will try to test it this evening. I will let you know.

[warrenoliver]

DAMN!!!!!! This thing is frustrating me.

When I check the sockets for the pump relay, I have 12V at 30 and 85 (3 0-clock postion). I have ground at the 86. When I jumper from 30 to 87, the pump does not turn on. When I jumper 85 to 87, the pump turns on. When I attach a jumper from the fuse to the 30 leg of the relay, the pump does not turn on. I have tried this with 4 separate relays that work in the headlights so I know they are good.

What gives? I know I am missing something obvious. (IMG:style_emoticons/default/chair.gif)