TX-Techman

Hi all, I am having an ignition issue with my 69 350/300, AT. It has an Edelbrock Pro-Flow EFI with matching Mallory distributor # 6148201, Accel 8140 coil, and converted electronic tach. The ballast resistor is bypassed per instructions for this setup.

The issue is that it has stalled on me a couple of times after a 20 minute drive and both times after setting for 15 or 20 minutes it will restart and make it back home with no issue.
Once it stalls it turns over, the radio and accessories come on but the ignition power seems to be dead. I did not have a meter to test if it is low or none but I know there is no power to the ECU or at least not enough to power the programming unit and the tach signal is also dead because it usually rotates clockwise when the key is turned on then comes back to zero. but when this happens the needle never moves.

It seems similar to a coil issue in the old days, so I am wondering if the electronics senses a shorted coil and shuts down to prevent damage or if the coils could be pulling enough to pull the power down enough to cause this issue. Regardless it does not blow a fuse and after a little time (15 minutes) she restarts and all is good. I checked the spark and it is definitely not good, it is bright orange instead of blue but cranks easily and runs good until it fails.

I have the correct coil in route for the distributor but I am not 100% sure this is the issue so thought I would see what the consensus on the forum is. Once I get the coil installed I will be carrying a meter, tow strap, and staying close to the home for a while :-)

Also I do not know if everyone is aware but both Mallory and Accel are now owned by MSD. Mallory production stopped on March 31, 2015.

Here is the blurb from the Mallory website. http://info.mallory-ignition.com/88-...-ignition.html
"In January of 2015, MSD Performance purchased the ACCEL Performance Group. The MSDP Group, a global leader in vehicle aftermarket performance ignition and tuning technology, made the decision to merge the top two companies in the automotive ignition industry worldwide—MSD and Mallory. Mallory will no longer manufacture its product line after March 31st. However, MSD will produce and service Mallory distributor replacement parts such as caps, rotors, points, and nearly 100 other items."

zuendler

Could be an overheating issue of your EFI box.
Causes could be mounted in hot location, or too much load from the coil side.

TX-Techman

Thanks for your reply. The ECU is in the jack storage compartment and the commonality is the tach and ecu share the same ignition power. I really think coil but it seems odd that it would not blow a fuse if it had that much load, I tapped the power from the IGN tap on the fuse block. I assume that is fused but need to check.

zuendler

Usually electronic devices have a internal temp sensor to protect the circuit from overheating. (For example audio amplifiers)
Then they just shut the system down and need to cool down under a cirtain temp level.
And a iginition system has a similar circuit like an audio amplifier.
But the reason for your problem could be anything else as well. First I would check how hot the box is when it shuts down. Then you could try to cool it with a fan and see if it runs longer.

Sigforty

Maybe issues with the coil, like you believe. On my 71 after installing the MSD box I had to switch to a high vibration coil. For some reason the car started killing regular coils.

TX-Techman

the coil will be in tomorrow and I hope to have time to test and see if that resolves my issue. I am hopeful that is the case but not certain. The ECU is downstream of the issue, it is the power feeding the ECU that drops that is fed from the IGN terminal on the fuse block. I appreciate your suggestions and will post an update.