I have a '79 f-150, 351W with MSD billet dist. and Blaster II coil hooked up to a MSD 6AL.

Problem: Dies randomly at idle or at regular RPM range regardless of temerature. When it dies, it just shuts off like I turned the key. Sometimes I can go 100 mi. before it dies, sometimes after 30 sec. she dies.

I changed the ignition switch to no avail.

Any insight would be helpful. MSD has failed to respond to my problem.

 

Does it start right up when it dies? Does the radio stop working too? When it dies, check for spark and fuel. Look over all the connections at start relay, coil, dist, module, battery and ground to block. Make sure they are clean and tight. Also follow the wiring making sure no wires are pinched or rubbed. Let us know what you find.

Marty

 

It sometimes starts right back up, sometimes it has to crank over several times, which is normal. All of the electrical componants including radio and lights continue to work. All of the wiring/connections seems to be good and also well protected.

 

Have you checked for spark at the plugs when it dies?

 

This is an intermittent problem, so it's not going to be easy to find. You will have to figure out a way to test or monitor some things to catch it when it fails.

One thing I would look at, since your truck is older and has probably a lot of work done to it, is grounding. I assume you have the large ground wire from the battery negative bolted to the engine somewhere. I am also assuming you have your MSD box mounted on the firewall or the fender. I would make sure the ground for the MSD box runs directly to the engine block, with it's own ground wire. You may want to tie the MSD ground to the firewall or fender, and under the same screw run another wire from there to the engine block.

If that doesn't help, I would get a small 12 volt light bulb and some long wires, and hook the wires to the bulb. Take the bulb inside the cab so you can see it, and then run the wires out to the engine. Bolt one fo the wires to the engine block, and put the other wire on something you want to monitor. The first place may be the + of the msd box. If it quits, you can quickly look to see if the bulb is burning in the cab while driving.

You can move this wire around to different things you want to monitor.

 

problem solved:
one can never put too many grounding straps in a truck