Intermittent Ignition Problem

[Cobra]

My engine has shut down while driving for no apparent reason. This has happened twice in one day. I have the 6al, Blaster SS coil and MSD distributor. This is frustrating having an intermittent problem because I can't test when everything is running fine. I have checked all fuel related items and even replaced the old Holley with a Mallory 140 pump. No water in the gas. No vapor lock.

So, I'm wondering where to start. The coil sits on a bracket just an inch in front of the cylinder head. Could the coil be getting too hot? I can put my hand on it when it is hot. Do these SS coils not like heat? Some guy told me that they will work or not, no in between.

The 6al is mounted inside of the car, up under the footwell, so it's way out of the heat zone.

Could the magnetic pick up inside the distributor be getting too hot and some wire inside is pulling apart, then re-joining when it cools down?

I'm sure you hate these kind of questions, it's like whats the next card in the deck.

I wish something would really fail then I would have a known part to fix. I'm a little leary of even driving the car for fear of being stuck out in the middle of nowhere.

Thanks, Mark
http://homepage.mac.com/sweetvenom/PhotoAlbum11.html

[msdtech4]

Mark,

When the motor shuts off does it start right back up or is it dead for a while? I agree intermittent problems are a major pain. The coil box and distributor are designed for under hood conditions so that really should not be an issue. The fact the box is in the interior helps but is actually not necessary. Give me a little more information and we will figure it out. By the way very nice cars!

Thanks,

MSD tech4

[Cobra]

The first time it shut down it wouldn't start right back up. I waited about 30 minutes and then it did start up. The second time I was in forth gear clipping along at a good speed and it shut down. I then coasted for a half a mile , turned key back on, in third gear, let clutch out and it fired up. Then I drove it on home 30 miles away and it ran fine. When it happened both times I was hot rodding it pretty good.

During the first shut down I took the coil wire off and tried cranking and got one big spark and then no others. Thats when I just let it sit for 30 minutes, then it started.

Any ideas?

Thanks, Mark

[msdtech4]

Mark,

In the instruction booklet for the ignition box there is a section under trouble shooting there is a section called testing for spark. Unfortunately you need to run the motor till it will not fire to do the test. I would highly recommend checking any crimps extensions etc on the wires going to the box. Make sure we did not do a bad job and miss-crimp a wire end or something. The time it died for a half hour would indicate an intermittent problem in one of the components, box coil distributor, but the shutting of and starting right back up normally points at a connection or something. Make sure that the ground to the unit is ok, that the ground from the battery to the block is in good shape etc. But really look at the harness on the box to coil, box to distributor and box top battery.

thanks,

MSD tech4