Thread: stumbling 502 update....MSD box not grounded???

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Thanks everyone for the advice. After doing some investigating...I discovered that my BG 850 was really a 750. Not a problem....I'de rather give up some top-end for a better signal and throttle response.

With this in mind...I decided to get a rebuild kit and take it apart to clean it up. I had noticed that the boosters didn't flow nice and even like they should. In fact...one of them would drip real un-even as I revved the motor. I still don't think this would cause all the back-firing, and fouling of plugs, but since I bought the carb used, I thought it would be a good idea anyway. Get it right, and mark it off the list as a possible problem. Done.

Secondly...I headed over to my local speed shop and bought the curve kit for my MSD #8361 distributor. I put the lightest springs, and the smallest bushing in it to get the "steepest" curve I could. Mark problem two off the list. Done.

Then I started it...carb works MUCH better, but I still have the same problem with cylinders coming and going...backfiring, and just plain ole sucky performance. Now I'm thinking its something wrong with the MSD-6AL, (or more likely...my wiring). Has anyone out there had problems with their MSD-6 unit? I get the feeling its not grounded...or the motor's not grounded...or maybe its not getting a full 12volts? Anybody ever had mysterious cutting out and plug fouling with an MSD?

This is my first time with a MSD unit, and I know I got it hooked up correctly. But maybe its not getting grounded to the motor?

Any suggestions?

-CJ

Originally posted by 4speedfunk


maybe its not getting grounded to the motor?

Any suggestions?

-CJ

I would try running a ground wire directly from a bolt on the engine to a mounting bolt on the MSD box???

I don't mean to sound rude but have you tried using a voltmeter to locate the problem?

Abe

i personally had the same problem ,however my problem ended up being a needle and seat not fully seating . i took it out gave it a couple of shots and bingo. problem solved.

Abe....Yeah, the volt meter idea is great, except the problem comes and goes, and rarley does it sitting in the driveway. The misfire and stumbling happens when I take off down the road, under load. This makes it kind of difficult to read a volt meter, drive, and shift gears. Not to worry....I'll get it figured out. I'm going to rig up a "temporary ground loop" connecting the motor, frame, chassis, MSD, and battery all to one negative source...and see if that makes a difference. Update coming soon.
Thanks-CJ