Ignition issues

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Joined
Nov 8, 2010
Messages
119
Reaction score
1
Location
Choctaw, Oklahoma
My Car
1973 Mach 1
351c 2v
Edelbrock 4bbl, Performer Intake
Ram-Air
Pertronix Electronic Ignition
Alrighty,

The issue started this morning. Intermittent. Runs very rough. I watch the tach drop in and out. At first I thought higher RPMs were solving it but thats not it because it gets bad at higher RPMs as well. Fuel and Air aren't the issue. All my wires are on tight. This problem hadn't started until this morning. Goes away at times and then comes back.

I really want to say it is electrical but I have no idea where to start.

Pertronix and the Flamethrower Coil on a stock Distributor. Plugs, Wires and the Ignition System are just under 2 years old.

Dunno where to start troubleshooting.

 
If you think it is electrical, reinstall the old coil. It is a quick and zero cost first step in fault isolation. Just a thought. Chuck

 
You know, it could possibly be bad gas. I can pick up an additive.

The tach is an aftermarket that is strapped to my steering column. (No stock tach, dummy lights [for now]).

I dont have a stock coil but the auto hobby shop likely has an extra lying around that I could at least use for fault isolation.

Thanks for the suggestions. Anything anyone else comes up with is welcome.

 
Bad ground somewhere in the primary ignition system?

 
This evening, take your car to a PITCH BLACK location. Open the hood. Start the car. See if you have any lightning under the hood.

If you do, there you go.

You can also do a few ignition checks with the voltmeter. Make sure you are getting a solid 6 volts across the coil when the points are closed. Since you don't have points, you will have to do a little guessing.

Also, make sure you have 12 Volts across the Pertronix ignitor with the ignition on. It doesn't like anything under 8 volts.

 
Not to highjack the thread or nothing but i have a question. If the stock tach starts to go bad can that cause an intermittent miss?? My car was doing that this summer. Just out of the blue it would miss run like crap then quit missing and run great again. I have noticed that my tach has been acting up alot and i have to smack the dash to get it to work again. Just wondering if that could be the problem?? Everything else in the ignition system is new. MSD dizzy 6al and coil. New alternator and starter and wiring harness for alt. all new but still had the miss this summer. Just wondering , sorry if i highjacked this a bit but i was just curious.

 
Not to highjack the thread or nothing but i have a question. If the stock tach starts to go bad can that cause an intermittent miss?? My car was doing that this summer. Just out of the blue it would miss run like crap then quit missing and run great again. I have noticed that my tach has been acting up alot and i have to smack the dash to get it to work again. Just wondering if that could be the problem?? Everything else in the ignition system is new. MSD dizzy 6al and coil. New alternator and starter and wiring harness for alt. all new but still had the miss this summer. Just wondering , sorry if i highjacked this a bit but i was just curious.
It depends if the tach is IN- LINE to the ignition coil. The stock tach is wired in line to the coil. Remove the tach and you have an open circuit and therefore no power at coil.

The easiest way to tell is to disconnect your tach and see if the motor still starts. If it does, chances are your tach is not affecting your coil...unless it is shorting to ground.

 
Alrighty, update:

Got some of the STP stuff in the orange bottle and added that to the tank. Also got under the hood and rechecked every connection I could find to make sure they were well seated. The problem did not occur again today in over 2 hours of total driving.

If it does resurface, I will begin troubleshooting with the electricals. Thanks for the input everyone.

 
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