Re: More HEI questions for \'88 4.2
Screw the spare module.
If you have a spare one, screw it right to the fender well next to the one you are using and tape the connectors over to keep the crud out.
If you want to make the one you have live,
Add a ground wire (14 Ga.).
Splice into (SPLICE, don't cut) the module Black wire, and run that to the battery negative or the primary ground.
(Primary ground would be the negative battery cable that is supposed to be under a starter bolt if you have been paying attention....)
90% of modern module failure is from no ground.
(The other 10% is leaving the key on without the engine started)
The entire primary ignition system tries to ground through that black wire, and it tries to ground through the distributor to block connection.
If the block looses ground, the module takes the beating.
If the Distributor to block connection fails, the module takes the beating.
If any of the connectors get corroded, the module takes the beating.
Do your self, and the module, a favor and spend $0.05 for the wire and tape...
On the same note,
If you add ground wires to each head (14 Ga.), you will save your coil a bunch of aggravation also....
If you add a 10 Ga. ground wire to THE ALTERNATOR CASE (not a mounting bolt or bracket) your alternator will treat you much better.
Head bolts, intake bolts, exhaust bolts are no guarantee anything is getting a good ground.
Those bolts were NOT designed to keep proper electrical contact.