Thread: fuel injection wiring in 1990 range rover

Its a bit hard from your post to help.

I guess the first thing I would do is connect what is obvious.
There are 10 Injection plugs. 8 go on the injectors and one on the water temp sensor and one on the fuel temp sensor. Look at the wiring diagram to check the correct colours. The water temp sensor is at the front of the manifold on the RH and is attached to the RH injector bank loom. The fuel temp sensor can be on the front of the fuel rail on on the LH side.

There is a sub loom to the MAF ( 4 pin flat plug) and this will also have a wire which goes to coil neg.

There is a sub loom to the stepper and this has a square plug with 4?wires.

There is a sub loom to the TPS ( on the throttle body)which has a round plug. this should be with the LH injector bank loom.

There is a sub loom to the fuel vapour purge valve which you probably do not have .

The rest of the plugs will go under the dash, but this should be obvious as there should be a big grommet on the loom where it goes through the firewall.
You will not have a speed sensor wire, which you probably do not need.

There will be a wire to go to the fuel pump relay, which you probably do not have yet.

That is a start .
Regards Philip A

You'll also need to use an EFI tank with intank pump, or set up a lift pump with surge tank, also the EFI tanks have different mounts on the back, 2 bolts as opposed to 3

thanks for that Phil, I spent last night with old and new looms and have a managed to get my head around all the injectors and stepper motor wires ,etc, what has got me foxed is there are two plugs that are on the fire wall. On the original loom the wires agree with the wiring diagram for a 1990 range rover, on the new one the colours have no correlation to wiring diagram that I have. The loom I got came with a ecu which is marked as being built in 1991. I am not sure if they changed colours or diagrams in the later models. hence my problem!!!! *#(^@$) if you get my drift
timothy

See if this helps. Just fitted a 3.9 to my 78 rangy
You only need to use 3 of the wires from the white multi plug at the firewall end and none of the wires in the black multiplug (its for aircon)
Orange and Green is 12v from battery
White and grey is 12v from ignition switch
White and purple is power to fuel pump
my loom is from a 93 rangy the colours didn`t match the hayne manual.

Ian

Originally Posted by Brute

See if this helps. Just fitted a 3.9 to my 78 rangy
You only need to use 3 of the wires from the white multi plug at the firewall end and none of the wires in the black multiplug (its for aircon)
Orange and Green is 12v from battery
White and grey is 12v from ignition switch
White and purple is power to fuel pump
my loom is from a 93 rangy the colours didn`t match the hayne manual.

Ian

Unless of course you want A/C input, speed sensor input etc all for idle up facilty's to prevent stalling, but that will run it

Just an idea which is a bit tedious but foolproof way of telling which wire is which.

The 40 pin plug pin assignments do not change on a 14CUX from year to year.

Take the rubber boot off the 40 pin plug then note which colour wire goes from which pin. The manual has the pin assignments noted in the Fuel Injection section and the pins are numbered (tiny).

So by tracing the wires along the loom you will be able to tell which wire does what. I suggest that you get some masking tape and brand the wires as you go.
Regards Philip A

Originally Posted by PhilipA

Just an idea which is a bit tedious but foolproof way of telling which wire is which.

The 40 pin plug pin assignments do not change on a 14CUX from year to year.

Take the rubber boot off the 40 pin plug then note which colour wire goes from which pin. The manual has the pin assignments noted in the Fuel Injection section and the pins are numbered (tiny).

So by tracing the wires along the loom you will be able to tell which wire does what. I suggest that you get some masking tape and brand the wires as you go.
Regards Philip A

Thats a big ass task, I'd just source the appropriate diagrams, They are a bit pish posh in color coding, but relatively simple to work out the ones required and some continuity testing with a multimeter will have it on its way

funny but that's what I am doing at the moment and it is definately not my comfort zone, but I would also like to transfer the whole loom and dash, switches, etc I am not sure what century this all going to be finished, but hey whats time got to do with it, cheers !!