Originally Posted by Nickolas
So I replaced my Duraspark ignition module due to it being flaky as hell.
I went with a E-Core Coil and Hybrid HEI stand alone setup based on Jeep Hammer's as in the pic attached.
The only difference I did was run a wire from HEI "C" to the ground on the original coil connector so that the stock tachometer works.
There is no 'Ground' on the stock coil connector.
There is POSITIVE & NEGATIVE, or RED & GREEN.
So I got it wired up and it ran quite well and I drove it about 50 miles throughout the day, but the timing was all wrong.
So I go in and regap the plugs to .45 and set the timing to 9* at 800rpm idle.
Don't care for the 800 RPM unless that curb idle out of gear on an automatic transmission.
Should idle around 600 or 650 with no issues at all.
It now runs beautifully compared to how it was.
The idle is a touch high, but acceptable for me and it revs real smooth.
However the ignition will just die after a little while of use.
If I wait a minute I can restart it and it'll go for a bit before dying again.
If it cools down completely, will it fire up and run several minutes again before it dies?
That is a dead nut sign of over heating something.
The module, the trigger in the distributor, something...
Also turning on the headlights will kill it once it's restarted.
That sounds like a voltage delivery issue, which you should NOT have with a relay in the circuit.
If you have the relay, and it's working properly,
Then you have a NEGATIVE PATH ('Ground') issue.
'Ground Path' issues are not uncommon, especially if you are using the distributor housing as the 'Ground' for the ignition system.
The alternator is working well and the battery seems fine.
I have the Coil voltage wire running straight to the battery terminal simply because I had a lead hanging off right there and I didn't think it'd matter vs it connecting to the starter solenoid.
Battery connections are guaranteed corrosion.
Common lead/acid batteries leak acid around the terminals, there is no way around it. Period.
Every battery leaks acid around the terminals, even the 'Gell' cells and AGM batteries, not just as much...
I'm curious about the relay still...
I'd think the HEI module was overheating, but then why would turning on the headlights seem to affect it?
That makes me think it's some sort of voltage issue, but it will crank over just fine.
Thoughts on why this could be happening?
Voltage would be easy to track, simply connect a volt meter to the module battery connection,
Have someone turn on the head lights, see if the voltage drops as the engine dies.
'Ground' or Negative path issues will be a little more tricky to diagnose.
Check for RESISTANCE between the point where the ignition 'Grounds',
Distributor housing at the block, or where ever you have the circuit reach final 'Ground'.
From that 'Ground' point to the battery negative terminal,
Read the resistance, then start the vehicle.
If the resistance shoots way up, you have a 'Ground Path' issue from ignition to battery.
Dedicated 'Ground' wires are always a good idea,
And it's pretty simple to run a wire to the engine head(s),
Then to the alternator, splicing in a wire to the ignition along the way.
That way the engine head gets a 'Ground', so the spark plugs and sensors can work correctly,
The ignition gets a dedicated 'Ground' path,
And the alternator CASE gets a dedicated 'Ground' path to complete it's circuit.
Now, since you made modifications, I'm not completely sure what you have done from your description,
I can't give you a dead nut diagnosis of the issues you are seeing.
The possibility you have a faulty module is high.
The possibility you have a faulty relay is high.
The possibility you have a poor 'Ground Path' is high.
Since you are connected directly to the battery via an 'Existing' wire,
The possibility of a bad connection due to corrosion, or a bad connection crimp is high.
Close inspection for corrosion, the 'Tug' (NOT YANK!) test on the connectors,
Checking for a solid engine 'Ground Path', the cable from battery to engine, and adding a wire from that large terminal to the alternator/ignition is always a good idea...
And it's also a trouble shooting technique,
Temporary jumper and issues goes away, you found the problem...