Motor has No spark?

No instructions on the gap, I just gapped close without touching the fins

When it has no spark at the plug wire are you turning it over with the ignition key?Also does the battery have a good charge in it?Did you try a different coil wire just to rule that out?Or could it possibly be the ignition switch?It seems like your getting spark when testing MSD box with just the key on but nothing when cranking.

Later Mark

I would also try replacing the rotor even though it's only a couple months old it almost sounds like it's not distributing the spark to the spark plug terminals on the cap.
Later Mark.

Mark Miller wrote:When it has no spark at the plug wire are you turning it over with the ignition key?Also does the battery have a good charge in it?Did you try a different coil wire just to rule that out?Or could it possibly be the ignition switch?It seems like your getting spark when testing MSD box with just the key on but nothing when cranking.

Later Mark

Yes I'm turning the motor over with the ignition. Battery has 12volts. I did not try another coil wire though. It has to be the distributor because the jump wire worked with the same wire so i guess that rules the wire out. Maybe the pickup or magnet is defective. I'm gonna buy an ohm tester tommorrow and figure this out. Thanks for all the help because it truly does help

Curt wrote:

BigDave65 wrote:Make sure you have 12v going into the MSD and a good ground.

Yeah, 12v straight to the battery, and ground straight to the battery.

Do you have a good ground between the battery and the block & heads?

bad pickup in the distibutor

Both heads on the block are both grounded to the motor plate brace with 1/2 inch thick ground wire. I will ohm the wires from the distributor today. This will tel me if the pickup is bad or not. It cant be much.

If all else fails, give MSD Tech a call. There usually smarter about this stuff than we are

She is back running again, but smooth idle and all the way till around 3000k......breaks up real bad. Never done this before. Gonna change the plugs and re-gap them. Hope this works.

What did you do to get it running again?

Later Mark.

Honestly, I just went back over everything and made sure everything was back right and she fired. I don't have a clue How, but it works now. Weather could of had an impact on things because the car sat for a while and while I wasn't getting spark alot fuel got into the cylinders so that may have had a impact on it as well. But now the car breaks up real bad after 3000k and don't know why. Runs nice and smooth till around 3000 rpms and breaks up REALLY bad.

Car does idle much better with timing locked out. More throttle response as well. Now I need to figure out why it breaking up after 3000rpms

Is it misfiring because your throwing too much timing at it? Maybe it doesn't like that amount of timing at the higher rpms, I have no clue. Aren't you running this motor on pump gas?

bb429power wrote:Is it misfiring because your throwing too much timing at it? Maybe it doesn't like that amount of timing at the higher rpms, I have no clue. Aren't you running this motor on pump gas?

I ran this motor at 36* for many races and she never did this. Ever since I locked the timing out she acting funny on me. I even used another distributor and it still does the same thing. This motor is 9:8:1 compression so pump gas and the timing was never an issue. The timing dont move now so I know it aint climbing on me while above 3000k. So that cant be the problem, or i wouldnt think so anyways.

1Bad91 wrote:...Ever since I locked the timing out she acting funny on me. I even used another distributor and it still does the same thing.

What about rotor phasing? I was feeling solid on the recommendation until I re-read you had swapped distributors...but still... are you sure it was good with both?

I wondered this as well, but is the other dizzy you used a known good one?

Yes, the other distributor is off my dads BBF foxbody car. Ran on his car fine. I'm thinking it may be the Digital 6 Box. Not sure what else it could be other than the coil, but the car gets spark. I moved the rev limiter from 7000 to 9000 and the car broke up more around 4000 rather than 3000. I don't know about this box but it could go bad after 5 years, could it not? Damn, almost want to buy new coil, distributor, and box but thats money I dont really want to spend. I'm gonna try another box and see if the box is the problem. Car fires up and runs nice and smooth till around 3000 and it breaks up and sputters bad.

I think you may have narrowed it down to the box then... I've read about them going south plenty of times... No particular model either, unfortunately. I'm running a Digital 6 myself but have minimal hours on it so far..

I would say my Box has around 400 passes on it and plenty street miles too. Looks new as hell, but got some miles on it for sure.

Buy a new box and send that one in to MSD and have it reconditioned I don't recall the cost but it is fair then you have a back-up.

I had a similar problem and it turned out to be a cracked magnetic pick up, it only did it every once and awhile so it drove me nut's until I replaced just about every component. The pickup was the last piece in the electronic line.
John F.

Isn't 3000 rpm where an MSD switches from multi-spark to single?

BigBlockRanger wrote:Isn't 3000 rpm where an MSD switches from multi-spark to single?

YES it is, never thought about that before. I think your on to something here.

Just used another box......Turns out I have a bad Ignition box.....

Also double check your dial is set for 8 cylinder engines (should be #2 on the dial or #6 of you are using the 20° start retard)