I bought myself a 1997 Discovery with 118k miles on it last week for $500, the catch being that I had to tow it home on a trailer. I've ironed out all of the other major issues, and I'm currently trying to get the fuel pump to run the way it is supposed to.

I have no power at the pump, and the engine runs great when I put 12v directly to the pump. I've checked the fuses, inertia switch, and replaced the multi function relay. I've got power at the fusebox, and I'm basically just tracing back from there. I've also checked the wiring harness connector under the truck and found no obvious problems.

It seems to me that either my second hand multifunction relay is faulty and I have two non functioning relays, or that there is a broken/faulty wire somewhere. Is there some other component that would prevent the fuel pump from running but still allow the truck to start, run, and drive fine? Is there a way to verify the function of my relays?

Thanks!

 

First, get the manuals... (can also be found in the discovery Series I Tech section sticky thread)


https://www.cubbyusercontent.com/pl/...0Discovery%20I


wmlj970e.pdf = workshop manual....aka: RAVE. The bible for these trucks

etlj970x.pdf - electrical troubleshooting manual.

hl01561n.pdf - owner's manual... highly optional

from the electrical manual.... looks like you need to check out connections C277 (behind the fuse box under the steering column) and C407 (near the frame by the left rear tire). Pictures of the locations can be found in the electrical manual.

 

I checked both connectors and everything seems in apparent good order. I also tested for voltage at the connector under the truck (C407) and got a reading of about 30 millivolts...

Would I be bypassing anything critical if I run a new wire from the inertia switch back to the pump?

 

My inertia switch checked out good, but the wire connector at the switch was burned causing an intermittent problem. Take a good look at the connector and at the wires going into the connector. They may be oxidized and not passing power through the switch, or to the pump. I fixed a lot of connectors on my D1 to get it to work.

 

Well, I pulled the headliner down yesterday so I can recover it, and while I was up there I inspected the wiring harness.

I found a wire with some broken insulation, so I went back up the harness a bit and spliced a new wire to the pump. Everything is working as it should now!

 

My 95 Discovery had no power to the fuel pump.
I destroyed the dash trying to get to a non existent spider.

I checked all the relays and fuses which were okay.
I noticed that one of the relays out of the half dozen had normally open
and normally closed contacts, all the others were on/off.
If you wished to show an error condition that is what you would use.

I noticed that it was permanently energised.

I took it out and jumpered the non energised contacts Voila my pump works!!!

I have power to the coil but no spark, I suspect the Hall effect transducer.
The journey continues.

 

I only have one relay on top. Do you by chance know what color wires run to the fuel pump relay?

 

Ok got it running, it was the inside connection on the pump it's self. Now I have a ton of lifter chatter. Figures