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Mixing Systems - ECU & Dual Sync Distributor

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I am chasing some electrical gremlins and wonder if this could be part of the issue. The system runs fine however there is an occasional 'loss of ignition' in which the vehicle dies. Give it a couple of minutes and all is well. No other symptoms, warnings, or indicators in the log files.

1) My distributor is a Holley/MSD Dual Sync distributor. It uses two Hall Effect sensors to get the trigger and sync signal. The hookup requires 12v connection and chassis ground and sends out two signals.

2) My ECU is a Performance Electronics 8400 which uses a 5v sensor system however, the input signals can range from 5-22volt.

I have the system up and running. I've tried grounding the Distributor thru the sensor ground of the ECU (5V) and also to the chassis. I don't see any difference in operation.

I've talked to MSD and they say they can't comment on the system, they can only advise if it were hooked to a Holley ECU. No Help

I've talked to the developers at PE and they say 'I don't know".

Since I've seen it run on either connection, my gut says 'no big deal'. But I am also aware of issues generated by ground loops and wonder if this could figure in.

Anyone have any ideas or comments.


Trigger sensors should be connected to sensor ground. Although that is very unlikely your problem.

What makes you think you have a trigger issue? Does the ecu software show RPM when you are cranking it in the “no run” condition? Does the ecu have a trigger scope function or internal logging?


Thanks for joining in. I don't see a trigger issue - what I am seeing is an intermittent ignition failure and I am not able to find the causation.

While cranking, the trigger and sync signals are present. My logs show RPM at the point of failure so I think the trigger and sync are working, but the ignition is turning off.

My suspect is the coil but I have not been able to replicate the issue. It just occurs. I was tracing wiring to check for loose wires and when I found the sensor ground/chassis ground issue. I wonder about the possibility of the ground issue could be causing the ECU to turn off the spark control. My logs haven't shown that yet but again, I am not able to replicate the issue although it has occurred about 5 times.

Again, I am grasping at straws, trying to find something wrong when it hasn't broken 100% yet. Just curious if the potential for a ground loop could be a factor.

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