Help- my 4.2 v8 won't start!

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highweald

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Eastbourne
Hi, I'm new to this forum, hope someone can help me!
I've nearly finished building my hybrid 1950 80" with a 4.2 v8 efi auto in it, from a 1993 Range Rover LSE. I've wired it all up using the original loom and ecu and everything works but it doesn't start. The engine turns over but the fuel pump doesn't pump. If you run a seperate power feed to the pump it works but there's no fuel at the plugs, as though the ecu isn't telling the injectors and fuel pump to work.
It looks like I've missed out connecting up a wire that will tell the injectors, fuel pump and ecu to "talk" to each other. If anyone has any ideas, please let me know, it's all ready to go and I can't wait to hear that v8!
Cheers, Dave.
 
There's an inertia cut-off switch for the fuel pumps on the Disco's and probably the Rangies as well, there is also a fuel relay on the later ones.

Something to look into.

Peter
 
Thanks Peter,
I haven't got the inertia cut off switch in the part of the loom I'm using. If it's not there and so not wired in will that stop it running? Do you mean the fuel pump relay? I've wired that in as per the wiring diagram I'm using. Dave.
 
If it 'should' be there and isn't then the fuel pump relay won't work, as the inertia switch cuts off the fuel in the event of a crash, to stop fuel being pumped all over the place if a fuel pipe gets severed etc.

If the fuel pump relay isn't being activated, then you'll need to find out why and rectify the problem. You can try a direct feed to the pump and check that the pump is OK.

Peter
 
When you turn the ignition on, don't try to start the engine. Listen and you should hear 3 relays switch. One is the main efi power relay, one is the fuel pump relay and I can't remember what the other one is. But if you don't hear the relays switching you'll have hopefully found somewhere to start.
 
if its come off an LSE as i suspect, there are only 2 relays from under drivers seat,
and the inertia from the passenger side, and all those must be connected up correctly.
the old inertia switch had a blue connector, the later ones run into the loom, under the seat and across the bulkhead.rather than along the rear floor where feet used to break the wiring.
 
Thanks for all your help, I haven't got the inertia switch as part of the loom I removed and am using. Do I have to have one or won't it work without this at all? I've got one from another loom, do I have to wire it in. As for relays, I have the two but only one clicks- the fuel pump relay doesn't.
Dave.
 
If the fuel pump loop goes through that switch and you haven't got it, then you will have to either bypass the switch position or better still, fit the switch, it's a useful safety device. £5 on ebay for a secondhand one.

You then need to sort out what you have in the way of wiring, so you can identify the correct connections for the switch etc.

Do you know exactly from where the loom came, and have you got the details?

Peter
 
Peter,
It's the loom from a 1993 Rangerover LSE. I removed the engine and box from it myself and thought I had taken all the loom I needed, I didn't take the inertia switch as I didn't even know there was such a thing! Any advice you can give about wiring one in (I have an inertia switch on another complete rangerover loom (from a 1989 3.5 efi) or advice on bypassing it in my loom would be really helpful.
Thanks, dave.
 
OK, first of all, check the loom that you do have and see what spare connections, if any, you have.

The Inertia switch has a two-pin connector by memory, and if there's one of them spare in the loom, and it would mechanically be in the right position (bulkhead on the passenger side mostly) then you can check back with a meter to see if the pins on that connector go to the fuel pump relay coil.

One pin will be a feed from the ignition and one will go to the fuel pump relay. I don't think that the ECU has any control over the fuel pump directly.

If you can get hold of a RR Haynes manual for that year, it would help you check on the loom wiring colours etc.

I'll be down in Eastbourne in a couple of weeks to collect some metalwork, if you're still having trouble I could pop in.

Peter
 
Thanks everyone for all your help and advice. I've just been right through my loom again (for the millionth time!!) and checked eveything with my meter. One of my earths under the bonnet wasn't good, I just stripped & redid it and reconnected it onot the chassis. I turned the ignition key- the fuel pump relay clicked, the fuel pump started, then she roared into life!!! So It's now wire up all the lights and go and get an MOT.
Thanks again, Dave.
 
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