Hello everyone. This is my first post in this forum. I have an issue with my MSD 6a box and fan. The msd is wired directly to the battery positive, as directions state. The dual fan system is wired through relays, one to each fan, triggered by an adjustable in cooling fins type thermo switch. The positive for the fans is off the solenoid.

When the fans kick in, the idle falters for a second, as though sucking juice from the msd. How can I resolve this issue. Any ideas. And thanks for taking your time to answer.

kevin.

 

I would consider the grounds. We just had a post a couple of weeks ago where a poster had a MSD problem, and it turned out to be the ground to the box itself. He was using the isolation mounts, and was not getting a good ground to the box. He ran a ground wire from the box itself to the battery negative and his weak spark problems went away.

 

You asked this exact same question in the 73-79 forum a couple weeks ago. I took the time to give you a pretty detailed response, which you seem to be ignoring. What's the deal?

https://www.ford-trucks.com/forums/1...d-stumble.html