M40 to M42 swap complete. Temp gauge problem?

[///Harlis]

I've written this thread in e30tech as well. Just thought i'd try my luck here. Ive completed the M40 to M42 swap. everything works but the temp gauge just sits on cold all the time. when the ignition is in before i crank it its all the way over on hot. anyone had this problem? what do i need to swap over to get it working?
 thanks in advance

[Cristian G in Oz]

DO you have the M42 temp semsor fitted to the head (it's the one with teh single pin in it)? If so, are you using the M42 ECU loom? Ensure that you have the plugs connected up right, ie the 2 pin tem sensor is for teh ECU the single pin is for the temp guage.

Do you have the "chip" for the M42 fitted to your instrument cluster?

If you answer is yes to all the above it could be a "wiring" difference between M42 and M40 car looms, but I do know of other people that have done this swap without this issue.

Let us know how you get on.

Congrats with coming into the light with an M42:)

[///Harlis]

haha cheers. i'll look into it tomorrow and i'll let you know how i go. i used the m42 loom, and the ecu is chipped. so we'll see how we go

yes i can see the light now.

[hesgone2fast]

Same thing happened to me.
There are 3 plugs coming from the wiring loom in that area, two for water temperature, and one for oil pressure.
Play with them until everything works (temperature gauge reads ok, and oil pressure light is not on.

[EN318isPDX]

antispammer bump