Disco 1 1991 v8 fuel pump electrical wiring

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Skyisthelimit

Skyisthelimit

Member
Posts
23
Location
farm Adullan. 81 New Caledonia road. Piket-bo-berg
Hi, I would really appreciate some help. I live on a mountain and have been without a car for some time.

Just wanna mention that I'm perplexed about people that say negative stuff about Land Rover. It's the most industructable and unproblematic car I've ever had. Totally reliable. Only plastic and rubber that goes.

My clutch slave and master needed replacement and that was all that was wrong. When I found a mechanic to replace it, I wanted to drive it to town,so I bled the air out. When I tried to start it, it didn't wanna. I automatically thought battery, because of standing and tried to run start, but it didn't go. Someone tried to jump me. Still no luck. I put it on battery charger. The mechanic eventually came out and did slave and master replacement here and looked for fault. Petrol pump not running. He tested it with another cable off the battery and it's not faulty. I read on these forums that it could be relay or ECU. I found a wire that was corroded by brake fluid by clutch on inside. It leads to the fuel injection control unit. I fixed it and wanna test the car,, but mechanic took the plug that goes to the fuel pump apart and exposed wires for testing fuel pump and did not put it back. Can someone please tell me where the different wires must go. Also, please, if you can tell me what the problem can be
IMG_20240801_131916.jpg
 
Stanleysteamer said:
Any help?

Disco1 Wiring Diagram for Fuel System - Land Rover Forums - Land Rover Enthusiast Forum

Discovery I - Disco1 Wiring Diagram for Fuel System - Hi gang, 1997 Disco 1 V8, Gas. I am having one of those weeks. m\My daily driver died in a McDonald's drive through last night. Got it towed home and testing showed no fuel pressure out of the fuel rail. I have searched the RAVE high and low...
landroverforums.com
Click to expand...
Thanks Stanley. It's great to have in any case, but for now I just want the actual into the fuel pump part. Like the photo. 4 wires.
 
Skyisthelimit said:
Thanks Stanley. It's great to have in any case, but for now I just want the actual into the fuel pump part. Like the photo. 4 wires.
Click to expand...
Ok the green-black wire is to the fuel gauge sender unit from the guage, the fuel pump has two wires white-blue is the 12v supply to the pump from the inertia switch (fuel cutoff) plus a black wire to ground (earth).
Thats when your 3.5 V8 EFI disco left the factory in 1991.

After the inertia switch there is a fuse and then a fuel pump relay which is controlled by the EFI ECU.

So standard continuity fault finding from ECU, relay - fuse - inertia switch - pump… or in reverse if you wish, it’s up to you, a wiring diagram for that model year fuel injection system maybe handy 😊
 
discool said:
Ok the green-black wire is to the fuel gauge sender unit from the guage, the fuel pump has two wires white-blue is the 12v supply to the pump from the inertia switch (fuel cutoff) plus a black wire to ground (earth).
Thats when your 3.5 V8 EFI disco left the factory in 1991.

After the inertia switch there is a fuse and then a fuel pump relay which is controlled by the EFI ECU.

So standard continuity fault finding from ECU, relay - fuse - inertia switch - pump… or in reverse if you wish, it’s up to you, a wiring diagram for that model year fuel injection system maybe handy 😊
Click to expand...
Thank you so much. This will help me a lot I'm sure.
 
Stanleysteamer said:
Any help?

Disco1 Wiring Diagram for Fuel System - Land Rover Forums - Land Rover Enthusiast Forum

Discovery I - Disco1 Wiring Diagram for Fuel System - Hi gang, 1997 Disco 1 V8, Gas. I am having one of those weeks. m\My daily driver died in a McDonald's drive through last night. Got it towed home and testing showed no fuel pressure out of the fuel rail. I have searched the RAVE high and low...
landroverforums.com
Click to expand...
Hi Stanley. I still have problems. I'm busy going through endless amounts of videos and information to try to solve the problem. This wiring diagram seems to be from another car. Do you know where I can get one for my car. It's a bit confusing to me, as Im aware that some of the Land Rovers seems to share some diagrams. I just wanna check my logic with you please. There is power to the distributor, power to the plugs, plugs has spark, but injectors dies not get power. Does this mean a fault between the sparks and injectors? Like a bad wire? Or even the plug connecting to the injector? I'm also trying to work out how this relates to the fuel pump not going on with its own 12 v wire, but only with another that's run from speaker side. And of course a fuse that keeps blowing. What is all between spark plugs and injectors. What's inbetween ECU and injectors. The fault finding path you gave me is up to ECU, but I suppose I also need to know what's after that.
Stanleysteamer said:
Any help?

Disco1 Wiring Diagram for Fuel System - Land Rover Forums - Land Rover Enthusiast Forum

Discovery I - Disco1 Wiring Diagram for Fuel System - Hi gang, 1997 Disco 1 V8, Gas. I am having one of those weeks. m\My daily driver died in a McDonald's drive through last night. Got it towed home and testing showed no fuel pressure out of the fuel rail. I have searched the RAVE high and low...
landroverforums.com
Click to expand...
 
Your vehicle is extremely old, My RAVE manuals only go back as far as 1995.
And I am in the wrong country to look at my Discovery 1 Haynes manual.

I would hope that @discool and/or @sierrafery would be more use to you than me as I am not much use with electronics. Pre computer cars, I am fine with, but with the advent of ECMs etc I have to seek help myself.
Sorry to not be of more use.
 
Stanleysteamer said:
Is your vehicle right or left hand drive?
Click to expand...
Right hand drive. 1991, Discovery 1 v8 fuel 3.5
Stanleysteamer said:
Your vehicle is extremely old, My RAVE manuals only go back as far as 1995.
And I am in the wrong country to look at my Discovery 1 Haynes manual.

I would hope that @discool and/or @sierrafery would be more use to you than me as I am not much use with electronics. Pre computer cars, I am fine with, but with the advent of ECMs etc I have to seek help myself.
Sorry to not be of more use.
Click to expand...
No problem, you were very helpful and kind. I appreciate it.
 
Hi
Skyisthelimit said:
And of course a fuse that keeps blowing. What is all between spark plugs and injectors. What's inbetween ECU and injectors.
Click to expand...
1. which fuse keeps blowing?
2. the injectors and fuel pump relay are both hardwired to the ECU so if these are not getting power while the ECU does then the ECU is very suspect...
3. i doubt that you can fix this problem without a diagnostic tool which can run circuit tests on the ECU ... your vehicle has the normal OBD socket or the white square 6 pin diagnostic plug ?
 
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Thanks so much for your response.
1. Fuse B7 it looks like it's oil indication. I'm attaching a photo reference.
2. Unfortunately the first thing the auto electrician did was cut all the wires connected to the immobiliser. Even before diagnostics. The immobiliser was already professionally disconnected. So now it's possible that it can affect the circuit? I don't know if you read the story, but there was nothing wrong, but the clutch initially. Slave and master needed replacement. That's all.
3. Where do I look for this?
I also need to mention that when I went through wiring after everything I found quite a bit of wet behind the radio. We've had crazy amounts of rain. I've dried it by now. Just thinking that it can cause problems in the circuit.
 
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