Thread: 3.9 EFI D1 motor into my 86 Rangie

Ok, just been fitting the wiring loom to the engine, and going over all the wires I need to intergrate into the Rangie. Sorted just about everything, but I have come up with one wire I don't know what to do with - the vehicle speed signal wire to the ECU. The drawings in RAVE seem to show this coming from the instrument cluster. Being that the Disco had an electronic speedo, what signal does this need to make the ECU happy, and what will it do if I leave it disconnected?

I thought I once saw another thread on this, but I have been unable to locate it.

Thank - Gav

i do recall discussions on this, however i cant remember the exact outcome.
i think rovercare will have some info on this.... he's done enough engine/gearbox swaps to know, just have to pry him away from making babies long enough to get to a computer!

BUT, i'm pretty sure you can leave it disconnected if needed.

some help here maybe:
Rover 14CUX Hot Wire Mass Flow EFI: Service and Troubleshooting


i cheated an went after market ECU.

Originally Posted by bacicat2000

Ok, just been fitting the wiring loom to the engine, and going over all the wires I need to intergrate into the Rangie. Sorted just about everything, but I have come up with one wire I don't know what to do with - the vehicle speed signal wire to the ECU. The drawings in RAVE seem to show this coming from the instrument cluster. Being that the Disco had an electronic speedo, what signal does this need to make the ECU happy, and what will it do if I leave it disconnected?

I thought I once saw another thread on this, but I have been unable to locate it.

Thank - Gav

I talked about this when you came to work a few weeks ago. Mine is currently not connected. About the only issues it might cause are idle speed problems when coming to a stop and the carbon cannister won't purge correctly.

Originally Posted by BigJon

I talked about this when you came to work a few weeks ago. Mine is currently not connected. About the only issues it might cause are idle speed problems when coming to a stop and the carbon cannister won't purge correctly.

Thanks Jon - I knew it was you that had mentioned this before, but for some reason I thought you had posted about this somewhere, rather than discussed it in person - I guess my brain needs a rewire as well.

The carbon canister is still sitting on the floor, where it may stay... so that may not be an issue.

Originally Posted by PSI250

i do recall discussions on this, however i cant remember the exact outcome.
i think rovercare will have some info on this.... he's done enough engine/gearbox swaps to know, just have to pry him away from making babies long enough to get to a computer!

BUT, i'm pretty sure you can leave it disconnected if needed.

some help here maybe:
Rover 14CUX Hot Wire Mass Flow EFI: Service and Troubleshooting


i cheated an went after market ECU.

I ran my supercharged 3.9 without speed sender no problems, the 14CUX is pretty primitive and should cope fine, symptons if it really wants it is hunting/stalling when comeing to a halt

So, finally back at it after a few weeks doing all the other things I should be. Everything is finished under the bonnet, apart from one thing, and I can't work it out - where does the hose off the fuel pressure regulator go??? I can find anything for it to connect to - I am assuming it just needs a vacuum feed from the inlet manifold, but I am at a loss of where this is located, as I don't have any spots left...

Any ideas???

Cheers - Gav

Originally Posted by bacicat2000

So, finally back at it after a few weeks doing all the other things I should be. Everything is finished under the bonnet, apart from one thing, and I can't work it out - where does the hose off the fuel pressure regulator go??? I can find anything for it to connect to - I am assuming it just needs a vacuum feed from the inlet manifold, but I am at a loss of where this is located, as I don't have any spots left...

Any ideas???

Cheers - Gav

The vac hose fits onto a small nipple on the bottom of the stepper motor housing. It faces the firewall.

That's probably why I couldn't find it...

Thanks - Gav