GrandSportC3

I'm having a problem on my ignition system of my '68... I don't know exactly what component causes that issue.. but I'm 90% sure that the MSD box (6 AL) is responsible... I drove 450 miles yesterday with the '68 and had several problems... The alternator stopped working and I had to replace it.. Another problem was that the car shut down in the middle of I-75 on the way to Satasota (where I went) and on the way back - the same thing happened... Each time - there was no spark at all at the spark plugs... After about 40 minutes trying to start the car - I got spark again and continued my drive... This has happened to me before about 2 years ago.. but I didn't check if I had a spark or not at that time... I also suspect that it has something to do with the temperature.. Each time that the ignition stopped working - it was on a very hot day (around 90 degrees with high humidity)...
Is there a circuit breaker etc in the MSD that shuts off for a period of time at a certain condition??? Does anybody know?? :confused: :confused:

brs6482

Sounds logical, however i have ran MSD boxes and distributors for years on circle track race cars and had no problems. I do mount them as far away from any heat as possible. On my race cars i keep them in the cockpit, and on my 69 i have it under the dash on passanger side. They are very tempremental when it comes to heat. Alot of the times the MSD coils will shut down from the heat under the hood as well. That will also cause a no spark problem. Hope this helps a bit.

71coupe

I would guess that the module in the distributor may be faulty (weakest link). The distributor will get very hot, especially on a hot day. If not that, the next thing I would check would be the pickup coil in the dist if MSD's use those.
Double check all of the ground connections in the ign sys, including the motor ground
:cheers:

GrandSportC3

I might route the box to the inside and see if it happens again... It's actually pretty far away from the engine.. but I don't know if it's far enough away...

GrandSportC3

If it is the distributor - what would cause it to temporary shut down??? BTW - my distributor is a 50000 Volt Proform HEI...

71coupe

That is a common problem for HEI's. Heat usually kills the pickup coil, but it can be intermittent. If the module goes, it usually doesnt turn back on. Guess which one is more expensive...

LAvetteman

Here is what I learned about MSD ignitions about a year ago when i Had ignition problems with my 71. Rule out all other potential problems before you suspect your box. Good thing about MSD they have a technical department you can send your box to, they will run it through all tests and can repair it if its broken. I made the mistake of suspecting the box first and paying MSD to test the box when it was perfectly fine. It did give me piece of mind and MSD did send an instruction manual with it that I didn't have before.

My problem was the pointless conversion pickup in my distributor, just as Lars suspected.

GrandSportC3

Was your problem temporary or did it permanently fail??

wacked

Mine burned out.

theandies

Are you using a rev limiter "pill"? I had a similar problem and when I removed my 5800rpm pill it started and ran fine. I have replaced the pill with a 6000rpm unit and it’s been fine ever since. If you are using a pill then remove it and drive around for a few weeks to see if your problem goes away. Good luck.


P.S. My 6AL is located on the inside rear of the passenger side front wheel well and this is the only problem I have had with my MSD setup. It also happened two to three months after I installed the MSD/engine. That was over 4 years ago.

Fevre

I would suspect the ing module since I have heard of them going on the fritz when bad and the car is hot; cheap and easy to replace and if that is not the problem throw the old in the car in case the new one takes a crap, always nice to have a back up.

GrandSportC3

good idea - thanks!! :cheers:

GrandSportC3

If the problem happens again - I'll pull the "pill" and see what happens...

LAvetteman

It was permanent. I had erratic timing at around 3k RPM's.

GrandSportC3

thanks!!.. I still wonder if the module in the HEI would cause a temporary problem if it's getting hot... :confused:


[Modified by GrandSportC3, 11:46 PM 5/3/2004]

71coupe

This is that part in the HEI that will give you the intermittent failure:


Here is a link that gives you a breakdown of the HEI:
http://www.rustpuppy.org/ignition2/Ignition%202b.htm

:cheers:

GrandSportC3

Thanks!! :cheers: