Any ignition guru's out there
 

While at Byron a couple of weeks ago the ol wagon was doing a pop-pop at the hit of the throttle, and then some mild missing at the top end. We tried THREE carbs, worked on the jetting each time, to no avail.

The folks at MSD said something about RF noise.

Purchased a shielded cable, redid the trounds, removed and replaced the multitude of connections from the changing of components over the years. Put it all back as per the MSD Tech Book (actually, the way it was but cleaner). Fired it up and it chugs and quits like it's out of phase. HMMMM. Took a spare main lead and changed the phasing. Oddly enough it ran the same. WHAT'S GONG ON HERE. Two slow records in IHRA is one thing, but a car that won't start is a real problem.

OH, a new coil too....

Is the MSD bad? I disconnected the tach and all perriferals and wired it as a straight MSD with the same results.

I need serious help - I'm no electrician.

Peace, Rev. Mopar you can Email me at Racewthrev@aol.com

make sure all your grounds have a good connection.
Also check all you wring for chafing or bare spots.

REV, IN ADDITION TO CHECKING ALL GROUNDS, MAKE SURE THAT YOUR BATTERY IS FULLY CHARGED. MAKE SURE ENGINE AND BATTERY ARE BOTH GROUNDS. AND HAVE YOU TRIED CHANGING YOUR REV LIMITER CHIP ALSO. ALSO CHECK THE CAP A ROTOR BUTTON. IF THOSE ARE ALL GOOD, AND YOUR ENGINE IS CORRECTLY TIMED, I WOULD SAY TO TAKE THE BOX TO BRISTOL WHEN THEY ARE THERE, AND HAVE MSD CHECK IT.

MYRONARL1119

An MSD ignition will work properly if you ground it with a rusty bolt. From my experience with their systems the only problems with EMI, RFI, electrical noise what ever name you want to give it has no ill effects on any but their Digital systems. You did'nt say if your timing appeared to be correct , which I'm assuming it is. Does the engine exibit black smoke, what do the plugs look like? Do you have good blue spark coming from the coil? If you don't own one I would get a spark tester and an MSD tester and diagnose the problem from the trigger source ( crank trigger or Dist. ) out . There are a multitude of possiblities you must have a logical and strategic approach which means you have to see what isn't the problem then eliminate down to the actual cause. Looking at the plus and for signs of black or gray smoke can be some tell tale signs. Unfortunately the new BUZZ words today for any mysterious missfire is always interference, RFI, EMI , back feed I've heard them all in 25 years of repairing cars and racing them I've yet to find any of them to be a problem. Good luck and please let us know how you're progressing. Joe

Rev.,check and make sure the two wires that run from the dist. to the msd box do not run close to the coil ,if it does it will cause a bad miss.

swap another crank pickup on it,I had a bad pickup causing the same type of problem.Does it have a start retard ? Disconnect it,seen weird problems with those also.

A simple thing for high rpm miss is to decrease plug gap. Try decreasing plug gap by 0.010" and see if it helps. If it does help, it's something in the ignition.

Chris Hill
Spec 125 Light

Check your distributor gear, disconnect the 2 step if you have one, and make sure your wires are compatible with the ignition box you are running, solid core vs. spiral core. Ground the ignition box directly to the battery. I also had a high end miss which was traced to the alternator I was running.
Good luck,

Joe Martens B/Stick 3969

Rev,
I had a problem similar to that, coulbn't find it. When the electric water pump was replaced (after it quit working) the problem was fixed. Maybe RFI from the electric motor??

Adger Smith

Can you humor us and let us know how its grounded.

I went through a problem with it breaking up which was caused by a lack of good grounds.
Brian