Odd problem with MSD and points dizzy.

[Al Weyman]

Don't know whether anyone can offer advise on this one but I have had on going misfire problems on my older car using an Accell twin point dizzy and MSD box. I took one set of points out as recommended by MSD but always had this high end misfire. When I installed a new engine I put in another Accel dizzy I had because it had the bronze drive gear for the roller cam abd forgot to take out one of the sets of points, no missfire but an erratic tacho and also another problem which I have never encountered before, sometimes under full wide open throttle it coughs then clears itself but not evertime. So i take one set of points out again after remounting the mSD coil vertically (it was horizontal which I was told was a no no) and the Tacho works OK but the the miss is back. Pops the points back in no missfiire but poor tacho and the coughing effect.

Now i am sure MSD Know what they are on when they say remove a set of points so it has me wondering could this effect be being caused by a duff coil and the extra dwell offered by running two sets of points may allow the coil to perform a bit better or run cooler but the sparodic coughing effect could be caused by the thing saying enough then cooling down again. Any thoughts on this, its not the problem fitting a new coil which I should have done its doing that then getting all the way to the track and still having the same problem.

[Tim Falce]

Just another thing to think of Al, do you have a rev limiter fitted? I had all sorts of mis-fires, pops and bangs which went on for around a year. I changed the entire system (Lumenition) and sent the module and coil back to be checked which came back fine. I ended up removing the rev limiter and it was fine after and I never had a problem since. I have since spoken to a few people who have had problems with rev limiters affecting hi power ignition systems.

[Al Weyman]

Mine is the older MSD that you cannot fit a rev limiter to so no I dont have one.

[GORDON STREETER]

Just a thought Al, have you checked that the voltage at the coil is within the parameters. (IE the alternator isn't overcharging ?)

[Al Weyman]

I can turn the alternator off and do for the race so not that.

[dikko]

Don't know anything about your set-up but recently had a problem with my car and a friend said he had the same...some sort of 'feed-back' thing with the rev counter argueing with the ignition system......

[Al Weyman]

Yeah could be, i am going to install this engine in my other car at the weekend as I have bashed the old girl so if the problem disappears it will point to something like that as I run an HEI MSD system in this car which normally runs clean.