[shift551]

Ok so here is the deal... I have a 1969 mustang with a 429. I have a mallory coil and distributor, electric fuel pump, and an optima battery. When I am driving the car it randomly will shut off. I can be either in motion or sitting still. I have replaced the coil and ignition switch as well as checked all my wires. I can get a consistant 6.75 volts to the coil. When the car dies it acts like it has lost all power except the lights. Its a clean shut down, there is no sputtering. Its like I turned the key off. I cann say with 99.9% assurity that the problem is not from a fuel issue. I have tested the distributor according manurfacturer and it checked out ok. I am at a loss. I dont know what to make of it. 5min or so later the car will crank after several attempts. What could this be? Has anyone had this problem before? Any idea what I should change?

[Desert Dale]

Hey Man! For your electrical problem, it's not what you should change, it's what you should repair. The 69 has been around the block a few times, and has had a lot of hands on it. I would get a friend to help you and start wiggling wiring looms and looking under the dash for exposed wires, etc. that can make contact with ground and cause your problem. Nothing more frustrating than to have that problem, but it sure is satisfying to find it and fix it. Patience and process of elimination will do it!! Good luck to you! Desert Dale.

[Mustang_Crazy69]

i would say voltage regulator but your battery dont die does it?

[The Greek]

I would also say voltage regulator, if the old mechanical type, get rid of it and install the newer type solid state type. The old type has mechanical contact points which can stick closed during high current load situations.The solid state units are cheap and very reliable,unless you are a purest and want original equipment. O.E. stuff is best if you buy like Echlin(NAPA) products. Personally go for the solid state unit,they last almost forever. Also check for a good engine to chassis ground. I hope you don't have those cheap temporary battery terminal connectors that clamp the battery cables down with two bolts and a strip of metal across the cable to hold it in place. Hope you win the lottery,LOL.---Chuck

[sutphen77]

Volt reg or maybe even the ignition switch. Change one at a time and see what happens. Does your car have a direct hot wire running to the coil/distributer, after thinking about it I dont think a regulator would stop the car in it's tracts as you discribed. If needed run a switched hot wire and see if it still does it.