Any ignition guru's out there

classof65 · 06-02-2007, 07:57 PM

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

fastracer482 · 06-02-2007, 09:55 PM

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

MYRONARL1119 · 06-02-2007, 10:46 PM

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

buzzinhalfdozen · 06-02-2007, 10:55 PM

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

MHoward · 06-03-2007, 01:29 PM

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.

Raceready · 06-03-2007, 01:46 PM

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.

Chris Hill · 06-03-2007, 01:55 PM

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

Joe Martens · 06-03-2007, 05:20 PM

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

Adger Smith · 06-03-2007, 05:52 PM

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

Brian Holcombe · 06-03-2007, 05:57 PM

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

06-02-2007, 07:57 PM	#1
classof65 Junior Member Join Date: Apr 2007 Location: Maryville, TN Posts: 37 Likes: 0 Liked 0 Times in 0 Posts	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

06-02-2007, 10:55 PM	#4
buzzinhalfdozen Senior Member Join Date: Sep 2006 Location: Bellevue Ohio Posts: 984 Likes: 0 Liked 11 Times in 8 Posts	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 __________________ Joe Buchanan SS/BX 3117

06-03-2007, 01:55 PM	#7
Chris Hill Senior Member Join Date: Jan 2002 Posts: 655 Likes: 8 Liked 244 Times in 26 Posts	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 __________________ Chris Hill https://ihmusedparts.com

06-03-2007, 05:20 PM	#8
Joe Martens Senior Member Join Date: Dec 2001 Location: North Olmsted, Ohio Posts: 787 Likes: 622 Liked 196 Times in 69 Posts	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 __________________ Joe Martens AA/Stock 3969

06-03-2007, 05:52 PM	#9
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	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 __________________ Adger Smith (Former SS)

06-02-2007, 09:55 PM	#2
fastracer482 Junior Member Join Date: Jan 2007 Posts: 18 Likes: 0 Liked 0 Times in 0 Posts	make sure all your grounds have a good connection. Also check all you wring for chafing or bare spots.

06-02-2007, 10:46 PM	#3
MYRONARL1119 Junior Member Join Date: Dec 2005 Location: COLUMBUS,OHIO Posts: 59 Likes: 0 Liked 0 Times in 0 Posts	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

06-03-2007, 01:29 PM	#5
MHoward Junior Member Join Date: Jul 2006 Posts: 51 Likes: 0 Liked 0 Times in 0 Posts	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.

06-03-2007, 01:46 PM	#6
Raceready Junior Member Join Date: Mar 2004 Posts: 34 Likes: 0 Liked 0 Times in 0 Posts	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.

06-03-2007, 05:57 PM	#10
Brian Holcombe Junior Member Join Date: Feb 2004 Location: Hamilton NJ Posts: 68 Likes: 0 Liked 0 Times in 0 Posts	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