No Power??
 

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Re: No Power??
 

Maybe at this point some dyno time might be a good investment.????

Re: No Power??
 

Is that supposed to be "MSD box"?

Re: No Power??
 

Ed
What did you find wrong with the motor. When I talked to you in San Antonio, you said the leak down and the compression test didn't look good.

Re: No Power??
 

I had a problem like that years ago when I had my chevy ll after weeks of tearing my hair out turned out to be a bad msd box. It didnt miss breakup just no power going down the track.

Re: No Power??
 

A really bad ground? New MSD box incorrectly wired on installation? Can you borrow another box after you check your grounds and installation?

Re: No Power??
 

Replace pickup with a known good one. better yet put new one on.

Re: No Power??
 

Is there a chance that the polarity to the distributor pickup was switched? That is all it takes to do some strange things with the MSD. The car will run fine, until going down the track, and then it will act like the rev limiter has been lowered. Good luck.

Sean

Re: No Power??
 

I agree with Jim, change the pickup. we had that same issue at a race a few yrs ago and change the pickup and the car ran fine!!

Re: No Power??
 

Just some random info about MSD's & other high current draw parts...............

The MSD 7AL depending on the resistance caused by the plug gap, high compression, rotor gap, sparkplug wires, load, RPM and anything else that makes it more difficult to fire the plug will raise the amperage requirement for the box.

Your power supply wiring should be capable of passing 15 amps on the positive AND negative side.....

All wiring connections should have crimp fitting (mechanical connection) and be soldered (electrical connection) and be covered with shrink tube to prevent corrosion.....

You MSD box will work perfectly until you the reach the point of needing more amps than your wiring can supply...

Had the same type of problem with a MSD 404 box 40 years ago and learned my lesson regarding resistance in the power AND ground side of wiring..

In the words of Stroker McGurt "If some is good, more is better and too much is just right"

Hope this helps,
Bob

Re: No Power??
 

Same here car lost 3 tenths in three passes. Changed everything but the windshield before finding problem with MSD.

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Pat at Techwest suggest I put a 10 gauge wire on the positive and negative post of the battery and run them directly to the msd box. Sooo I will do that and see what happens. Ed Wright offered to let me borrow his spare 7AL3. I will take him up on his offer and have it with me also. If no go then as Scott suggested we will dyno the engine and find out if it's the engine or the car. I can get it dynoed anytime I want for free so at this point im wishing I would have already done that. Thanks.

Re: No Power??
 

Batterys possibly? If its a plate style battery maybe they are loose inside causing them to touch? Thats a shot in the dark but who knows. I had trouble with my MSD box as well but it ran fine just had a top end miss that would flicker the tach on and off....but it sounded like valve float...chased it all year...it was the 7AL2 box. And I spoke with the MSD tech department several times and they swore it couldnt be the box. Go figure

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All this MSD talk makes me glad I bought something different 8 years go. Got a Mallory Hyfire VIIs and Unilte distributor and they have been flawless so far. Box is grounded under the dash and power comes from the factory ign switch. Has start retard, and I set the launch (4800) and high side (currently 7800) with the press of a button on the box. No chips, pills, add ons or complicated wiring and it's never needed a repair. Your results may vary!

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We have had good luck with Mallory Ignition boxes also,have dynoed Mallory to MSD with no difference in HP,Mallory is more user friendly.Before NHRA required Pro-Stock to have TCD,Traction Control Detection ,many ran the Mallory ignition boxes,I guess Mallory did not want to get in bed with NHRA.Bill C.

Re: No Power??
 

Look at the plugs. If they are dark, have MSD check the coil. If it's bad, PM me and I'll tell you what I did to fix mine. If you are at the track and can't have the coil checked, replace it. If that fixes it, PM me. The coil fix is only temporary. I chased a problem like this for half a season.