I'm almost ready to test out my home made engine harness. The only thing delaying me now is working out how some of the connectors should be wired.

Air temp and water temp sensors have 2 pin junior timers - does it matter which pin is which?

The coil pack and TPS have three pin connectors and I have no idea which pin is which. From memory, the middle pin is power but I'm not sure.

I'm using bullet connectors so I can swap them about but with 4 connectors in question the number of iterations I might have to go through to get it right (and engine started) are a little prohibitive. Note I am crimping connectors onto existing connector wires but there doesn't appear to be any commonality between the colours used on each connector - for example if they all had a black wire and a yellow wire it would be easier.

A forum member kindly gave me some advice on this previously and a handy guide identifying the various ford connectors. However this only shows what colour wires were used for each pin in factory installations, not what those colours went to. David, I think you didn't have a theory on this - would you mind sharing?

Any help appreciated.

Coolant and air temp are just variable resistors and dont matter, unless the coolant is dual purpose and the body is earthed - rare on 2 pin sensors.

Tps, centre is usually the wiper (signal) the outers are + & - you,ll need to work out which is which, there are a couple of paragraphs in the megasquirt manual about how ro do this.

Coil, pin 2 on the ford 4 cyl is +

[Edited on 19/2/17 by r1_pete]

Hello again Ron!

I'll check up & get back to you!

David

Ok then...

Mainwire colour (broadly speaking):

Red, Yellow, Green, Orange ... power in some shape or form
Brown, Black ... earth
White ... sensor signal


Should have said before - Pete is right re the pin numbers.

What I can add is that TPS pin 1 is earth, pin 3 is power