I have a long-standing ignition issue which has me flabbergasted.

The symptom is it randomly cuts out while driving. Power cycling usually kicks it back on without having to shift into neutral and start. Very rarely it will restart itself without the power cycle.

I have two ignition modules which have been tested as good. I have two coils as well as a CD ignition which all display the same problem. I have two distributors. I have two ECUs (but only one firmware). I have even powered the coil directly from the battery (via a switch) to eliminate the ignition key as a culprit.

What the heck could be going on?!

 

hard to say without any vehicle specific info


are you sure it is just the ignition system cutting out?


by firmware you mean what? is the ecm EEprom or insertable chip?


best way to isolate this concern is with a flight recorder. You can record and save all data and review later what signals are falling out.


with out this tool you best bet is to buy a subscription to identifix and search the fix for your symptom.

 

When the CD ignition plugged in, it will blink and chirp (not sure of the chirp is intentional) when it receives signal. When the ignition stops with that system it's pretty obvious. Less obvious with the HEI coil connected.

By firmware I mean the brick which you plug into the ECU.

I know someone who had access to some kind of auto repair database and said ignition module, which it wasn't.

Does anybody have any ideas what could be wrong?

 

Could a 3rd party alternator somehow be causing this?

 

the vehicle had a 20 year production run...knowing the build would save a lot of time here.

 

It's a '93 with a 'w' center port injection engine.

I just checked the voltage. I have a 4-post battery isolator and the batteries are being charged at 14.67 volts which seems high.

 

Hm, the alternator terminal shows signs of arcing. Going to be hard to get the nut off!

(yes, that is a 1ga wire. 7-strand, too)

 

Whew, what a bear! Finally got the nut off by turning the alternator 'round and 'round, which my back loved ever so much. Fixed the threads with a die (so mangled I didn't think I had the right size at first) then made a custom nut to fix the core issue.

I have a good feeling about this fix (mainly due to eliminating everything else). Fingers crossed!

 

DAMN IT!

The problem persists!