No Power??

jim morgan · 04-19-2012, 07:39 AM

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

Sean Marconette · 04-19-2012, 08:39 AM

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

Stephen & Horace Johnson · 04-19-2012, 10:43 AM

Quote:

Originally Posted by jim morgan

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

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!!

Bob Mulry · 04-19-2012, 11:49 AM

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

04-19-2012, 07:39 AM	#1
jim morgan Member Join Date: Dec 2003 Location: Wilson NC Posts: 106 Likes: 319 Liked 52 Times in 9 Posts	Re: No Power?? Replace pickup with a known good one. better yet put new one on. __________________ Jim Morgan 1916 , 9916 STK

04-19-2012, 08:39 AM	#2
Sean Marconette Senior Member Join Date: Mar 2006 Posts: 978 Likes: 800 Liked 276 Times in 77 Posts	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 __________________ Sean Marconette 84 Mustang 5060 SS/N

04-19-2012, 11:49 AM	#4
Bob Mulry VIP Member Join Date: Apr 2002 Location: Coarsegold, CA Posts: 1,016 Likes: 57 Liked 320 Times in 102 Posts	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 __________________ Bob Mulry 7516 STK A & M Motorsports