440beep

I recently installed the Mopar Performnce electronic conversion ignition system (orange ECU) on my 1969 Super Bee replacing the original points system. For the first start of the day the car starts with no problems, same for maybe second and third start. Then out of no where, I try and start the car and it turns over and over, but no start. Try again multiple times and the car is now completely dead, no sounds whatsoever. Try again and the car tries and tries and finally starts. The battery is fully charged and in good shape. Not sure the condition of the starter or age of starter.

Never had this issue with the old points system. Is the electronic ignition draining the system too much? Thoughts on other areas to trouble shoot.

440roadrunner

Boy, tough

Does it ever just quit while running? (I was thinking a defective ECU)

There COULD be a defect anywhere, in the harness connectors, etc

One thing I'd do is check the distributor reluctor gap, use a .008" (inches not mm) BRASS that is nonmagnetic feeler gauge to set the gap between the reluctor wheel and pickup coil. Check visually for any metallic chips or debri

Have you checked for spark, cranking, at the coil?

"Rig" yourself a nice big long clip lead, and hook ("hot wire") from the coil positive to the battery next time this happens, see if it fires.

Pull the harness connectors off the distributor, ballast resistor, and ECU, and examine them carefully, "fell" for tightness by installing / removing several times.

Are you SURE and I mean SURE that the ECU has a good ground?

440beep

Its never quit while running, once its started she's strong.

That reluctor gap could be an issue as I've struggled trying to get it gapped correctly.

Grounding the ECU box I dremeled the ECU mounting points down to bare metal on the firewall, and also ran a 10 gauge wire from the ECU mounting point to the grounding wire on the passenger side firewall from the motor (so I think its good).

Checking the coil I disconnected the coil from the distributor and started the car up and I saw spark jumping from the cable to a clamp (closest piece of metal).

Tomorrow I'm going to recheck the starter wiring again, and also get a new negative battery cable from battery to motor.

440roadrunner

Next time it refuses to fire, I would IMMEDIATELY check the spark at the coil while cranking.

Now you MUST simulate "real world" conditions, so this means you must test using the KEY and NOT by jumpering the start relay

So this means you must do some prep, unless you have 10' long arms!! LOL

Either "rig" a spark plug or get one of those spark testers. Think about this in advance so that you can see it while operating the key. Rig it so you can clip it to ground, and if necessary, buy some wire long enough to reach the tester, from the coil, so that you can see it, OR identify a plug wire you can rob and use between the coil and tester.

One like this:



Next time it won't fire, IMMEDIATELY install your spark tester, and determine right then and there whether you have spark or not.

IF not, clip a test lamp to the coil positive terminal, while cranking, you should have a nice bright light. If you use a meter, you should have "same as battery." That is, if the starter drags the battery down to 11V, then you should have very close to 11V at the coil positive.

I emphasize again, you MUST use the key for these tests, and NOT jumper the starter solenoid. This is because the coil bypass circuit is in the switch, AND

On most Mopars, the "run" circuit goes cold during "crank."

So if there is trouble in the start circuit/ wiring, you will not "see" this problem if you jumper across the start relay.

440beep

And so if there is no spark and the test lamp doesn't light up, what might be the problem?

bremereric

ECU, Ballast resistor or even the pick up coil in the distributor.

bremereric

I would even monitor the voltage when cranking. If you dive below 12 volts the ECU will fail.

440beep

I should mention an issue I did with the original install. I found I had wired the 4 prong ballast resistor incorrectly on the original install. It wasn't wired blue to blue and brown to brown, they were crossed and when we checked it with a test lamp with the key in the "on" position the lamp did not light up. Swapped the wires and it was fine. I had been driving the car for a week with it miswired (and had misfires, stumbling, etc). If my theory is correct and the ballast resistor was being bypassed, could the excess voltage have damaged the MSD coil? The MSD coil requires a 0.8ohm resistor.