Ignition Problems??
 

Guys

I completed a cobra build in the spring of this year. It is a 390FE, points system with an Accel coil. After completion of the car, I have put on about 960 trouble free miles. On my last big drive, I ended up on a rough road. I didn't think much about it - the car ran great - and I brought the car home. The next day, I started the cobra to head down for some fuel, the car was warming up in the garage - and as I pulled out to leave, the car backfired - sputtered - and died. I did get the car restarted but at low RPM, the car shook, backfired and wanted to die.

In my troubleshooting thus far, I have replaced the rotor and points. I gapped the points correctly. Then, the car started fine but when the engine got heat into it, it started to run rough again (no backfires). I got the car home from the test drive and convinced myself that it was a timing issue.

Today, the car started and ran great in the garage. Then, we hooked up the timing light and found it out of time. Next, we adjust the timing and by the time we got the engine in time, it was running badly again (with backfires - wanting to die).

Carb operation all looks very good. To me, it seems like it still must be an ignition issue. I am now convinced that I need to rid myself of points, condensor, and ballist resistor.

Is there something else I am missing??

Thanks in advance

Paul

just try another coil before you get nuts

I have thought about the coil. In your opinion, what do you see in what I described as being a "possible" coil problem?

Thanks in advance

Paul

A bad/shorted condensor will cause the problem too.

Be sure there is a Ballast Resistor in the circuit from the switched 12 volt source and the positive side of the coil. Without one the points will burn and the coil will overheat.

EDIT: The canister type coil should be mounted vertically so the windings within are covered with the oil inside which is a coolant. If a coil is marginal or on the verge of complete failure it will often times get an open circuit (fractured or broken secondary winding around the core) that will be problematic when it gets warm from current flow or conducted heat, for instance mounted on the front of a cylinder head. I personally like the "Anti Vibe" coils from MSD that are housed completely in epoxy. With the harsh ride that many of our cars have any edge you can find to fight vibration is advantageous.

A classic sympton of coil failure is that it will work when cool and fail when warmed up.

what threw a flag up for me was the description of a bumpy road you drove on.....coils don't like shock,

First thing to check is points,the gap,condition of contacts etc,work your way from there.Do you have a ballast resister?

Guys

All good information. I do have a ballist resistor. I have 960 good miles on the car before I started to experience these problems. I did find the points burnt and have replaced those about a week ago. New points in and have been gap checked. That immendiately had an effect and made the car run smooth. Now, once the car warms up, it starts to backfire and run very badly.

Paul

By the way, last night I ordered a Pertonix Ignitor II and Pertonix Coil II from Summit. It will be htere on Monday. Hopefully, that solves the problem.

Has anyone did this upgrade to their FE? Can I get rid of the ballast resistor with this new set-up? Seems like I read it both ways on the internet.

Thanks again

Paul