Hi,

ive just about finished my mk2 escort cossie conversion and im having some last minute wiring probs.. i cant find the coil +ve wire !!

Ive got some pics of some other looms and they have the coil wire coming out with the -ve coil wire clear as day. ive got the coil -ve wire but no +ve wire.

Ive traced all of the wires from the ignition amp, especially the black and yellow wire which is supposed to come together with one of the black wires from the ignition amp and go into the bit where there is that little black thingy that the coil +ve wire comes out of but ive got nothing like this.

and by the looks of it my loom hasnt been cut. from the ignition amp plug the black and yellow wire goes back for ages and then goes into two black wires one of which im supposed to wire to the ignition feed and the other goes to a relay. the two black wires from the ignition amp go back to the ecu and the green wire goes into that black diode thiny(whatever it is) and then goes to the -ve coil outlet.

can i just hook up a constant 12v supply to the coil ?? or can i cut into the black and yellow wire to go into my coil +ve ?? what is the significance of that little black box thingy that supposed to be at just before the coil wire ends ?

Is there different looms or is mne just stuffed ?

Any help would be greatly appreciated
Thanks,
Damion

 

You don't want a constant 12V on the coil because if the transistor that switches it fails then you will approx 10ohms or less across your battery.
2 things will happen.
1- your battery will discharge quite rapidly.
2- the wiring may heat up and lose its insulation if the coil resistance is less than 4ohms

12V\4 = 3A

If you can't find anything already there then your best bet is to add a separate wire grunty enough to cope with about 8-10A (to be safe) that is fed from the ignition switch.

 

wire the coil up as below - the black box is a capacitor against interference

 

Cheers kiwi cossie, would it be fine just to use the original mk2 escort coil +ve wire as it is a slightly heavier gauge than most of the other wires in that loom ?

jon@work: thanks for the info on the 'black box' ive already got that diagram.. its just that the wire coil +ve is not there

Thanks fellas.

 

You shouldn't have any probs but that wire is probably old which means the copper will be starting to oxidise slightly. THis means it will change colour and the resistance of your connection will increase.
Generally not an issue but if you have say 2A going through 0.5 ohms you have 1V across it. If the joint goes bad due to old age copper and oxidising then it might increase to say 3 ohms. THis will give you 6V exaggerated but you get the picture.

I would buy some new wire with a new crimp lug and you will avoid a potentially annoying fault. The beast would likely run with the old wire, but if you're not getting full volts on the coil then your spark will be weaker with reduced performance.

 

When i originally built the car a 3 years ago with a pinto, i had an auto electrician mate check out my wiring and he replaced my coil wire, so maybe it will be ok.

But yeah i might just buy a nice thick wire and replace it anyways.

Cheers.

 

ok ive conected up the standard Escort coil +ve wire and ive got it on a relay before it connects to the coil for a bit more oomph..

cheers.