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Efi wiring questions

Posted: Sat Mar 28, 2015 8:30 pm
by Sideshowkev
Hi,

I am currently installing a 1990 Range Rover v8 into an MGB GT and have a few questions regarding the wiring loom. Sorry this is the first ever conversion I have done so these may sound like daft questions.....

I have cut the plastic 8 pin plug off and connect most of the wires but I am left with a thin Brown + Orange wire which goes to the bank of injectors according to the wiring diagram. I have traced this through the loom and it is soldered into the other Brown+ orange wires. What does this connect to as it is already attached to the others?

I am not intending to use the lambda sensors on the car, can I just link them out or must you use a certain resistor?

The road speed transducer has a yellow connector which I can locate on the loom, do I need to connect the cars ignition to the other side?
I have purchased a new transducer which is cable driven off the LT77 gearbox but was wandering if I could use a SD1 transducer instead as I intend to use an electronic speedo?

I would be greatful for any help as I am no expert on car wiring.

Thanks

Posted: Sat Apr 18, 2015 6:21 am
by Sideshowkev
Anybody?

Posted: Sat Apr 18, 2015 6:50 am
by DaveEFI
Image

Dunno if this is for your exact version.

Posted: Sun Apr 19, 2015 8:54 am
by richardpope50
If it's a Hotwire EFI, I have a spreadsheet with all wires, their colours their connections and their purpose as well as the diagram as per above. PM me your e-mail address if you want it.

Brown + Orange are the 12v supply to the injectors (with the ECU earthing the other side to switch injectors on / off).

Posted: Sun Apr 19, 2015 11:16 am
by DaveEFI
It can be a bit tricky modifying an existing loom knowing what went where as the way is was made may not be exactly the same as the schematic - in terms of where splices etc are.

I tend to unwrap the whole thing and separate out each circuit - the looms are generally a bit scruffy anyway, and some bits will be no longer needed for MS so can be removed, and any additions made. Things like the injector plugs will often need new sleeving and boots. A spare complete inlet manifold etc makes is much easier to assemble the altered loom neatly on the bench. Do also draw out the dimensions of the loom between branches etc before unwrapping so you can get this correct when re-wrapping.

If you look at the schematic I posted, you'll see that N/O is used for more than just the 12v supply to the injectors.