Ignition wiring

[Chet Ruminski]

Wiring new ignition system. There are two wires marked S and I. Can I put both of these wires together and connect them to a separate switch connected to battery?

 

[mcmud]

No...those are separate circuits.
I may be able to help if I knew which ignition system you are you installing and into what vehicle?

 

[Chet Ruminski]

Motorcraft Module and distributor. Module has 6 wires Red and white ones next to each other and then another group of 4 that are Green Black purple and orange. The green goes to coil and the orange purple and black go to distributor. I think. Trying to figure out what to do with the red and white wires. Building a mud crawler and suing parts from 85 cj. I will put seprate switches for the ignition. Thanks.

 

[mcmud]

Yes... green to the Neg. coil, and the orange and purple should be twisted together at say three spirals per inch and should be shielded from any other wires along the entire path to the distributor.

Somewhere along the way ground the black wire between the connectors of the Ignition module and the distributor. I suggest you ground it to the block, if you also install a dedicated ground from there to the firewall and be sure that the battery neg. post is grounded to the firewall.

Assuming that your using the wires from firewall connector;
The red from the Ign. Module will connect to the #10 red wire from the run position switch which also supplys power to the positive coil and the I (ignition) on the Starter Solenoid whips or pig tails via a faint red resistor wire.

The white wire from the Ign. Module would connect to the blue wire running from the S (switch) on the Starter Solenoid and the start position switch. Typically this blue wire is spliced into one of two #14 white wires grouped together at the firewall connector just below and to the right side of the #10 red.

A bit of caution concerning the run position switch. If you leave this switch in the run position while the engine is not running it will cause both the Ignition Module and the coil to overheat and the module will soon be toast.

 

[Chet Ruminski]

Are you saying to run an additional ground from the black wire besides going to the distributor?

 

[mcmud]

Yes. Somewhere along the path, between the connectors at the Ignition module and at the distributor.

Wherever you feel as though it will be protected and convenient.

The module grounds through that wire to the distributor at the hold down clamp and at the cam gear.

Neither can be depended on as a quality ground.

Installing a ground along that path will assure that it is.

Many an engine miss can be attributed to the intermittent loss of that ground.

 

[Chet Ruminski]

Thanks millions. Incredibly helpful. Chet

 

[mcmud]

You are very welcome Chet.
It's simply information passed along down a line of jeepers.

I do want to clarify one point concerning the ground wire after re-reading your question.

Instead of adding another ground wire to the distributor my suggestion is to actually either cut away enough sheathing from the existing wire to be able to connect it to a stud, bolt or screw to either the engine if you are certain that it has a quality ground or to the firewall as it passes either of them along the path to the distributor.

Or to splice a wire from either of those into that OEM wire between the two connectors.

Both of these methods would still allow a quick disconnect from either the distributor or the module without undoing the ground.