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]

I think I have finally tracked it down. With the key on or off, I have 12V to the 30 pin which should be normal. With the key on, I have 12V to the 85 pin which is coming from the power supply relay. These are measured on my digital multimeter. If I jump from the 85 socket, the pump runs. If I jump from the 30 socket, the pump doesn't run. So I tested with a headlight bulb to see if i could draw power from the sockets. The 85 socket tests great, the 30 socket does not light the bulb. Since the 30 socket gets its power from the fuse, I checked with the fuse holder and it lights the bulb. So this leads me to believe that there is a break somewhere between the fuse holder and the 30 socket of the relay board. Until I get a good used relay board, am using a jumper under the fuel pump relay between the 85 and 87 pin - pump runs good.

I want to thank everyone for helping - especially Tom, Dave Darling, and John H (IMG:style_emoticons/default/beerchug.gif)


Warren