ConSeann3ry

So my truck wouldn't start up today. After a little diagnosis I found out that the fuel pump wasn't getting any power. I took out the pump relay/cut-off switch (both terms correct?) and there is power going to it.

From what I have found out is that it won't send power to the pump if the oil pressure sensor doesn't activate it. My oil pressure is hooked up to an external gauge, so I don't understand how this was part of it in the first place when it was working.

Most of the auto parts stores couldn't even find it in there computer, but the last one said they could order it and it would be 120 bucks. I'd rather not spend that money if I don't need to. I was thinking about bypassing this switch with a jumper from the hot wire to my fuel pump. Sound like an all right idea toyota gurus?

RobotMoose

iTrader: (1)

It would be safer to run your own aftermarket relay - basically one that can take the fuel pump's load.
What I would do is run two 14 AWG wires down to it on their own fuses (you can use in-line fuse holders), so there's power for the relay and the pump. Then run a 16 AWG wire back as ground from the relay into the cab, have it ground into you dash, and run a toggle on that leg, that way you have to pass as few wires into the cab as possible.

The other idea would be to find out the OEM relay's pinout and wire in an aftermarket relay on those leads.

vital22re

iTrader: (2)

what motor? I thought the old carbed motors ran a mechanical pump?

dropzone

iTrader: (6)

^^Some 79's had electric fuel pumps. .not even sure if there is a block off plate on the head so you could add a cam driven mechanical pump.

ConSeann3ry

Thanks for the responses guys. Weird stuff going on. When I tried to jump it from the connector my hot wire would go dead. But would have power as long as it wasn't hooked up to the other pin (going to pump). I eventually just ran a hot wire from the battery because I had to move it off the alignment rack. Showed a mechanic and he didn't get it either.

It runs, but there is a charge light still on. My tach (which is hooked up to the radio circuit) doesn't work as well. I am at work so have to wait until 5 to put a multimeter to the alternator which I suspect is probably fine. I don't see anything wrong with any of the wiring. Before any of this happened I was cleaning up under the hood with some brake cleaner so maybe that has something to with it.

To answer your questions about the mechanical pump, there is a block off plate on the head but no lobe on the cam to run it.

I know there is an 83 fsm download, but I don't think that would include the wiring I need. Seems like a short upstream from that cutoff switch connector, not sure what that has to do with the radio wiring. Anyways, I'll post back when I get it a little more figured out but if anyone has any ideas in the mean time I'm all ears.