I have a '93 383 cid that was done in '99.Last summer during a trip the engine died while crusing @ 75 on an interstate. I pulled over to the bern and turned off the key.Turned it back on and the engine started,drove it about two miles and it did the same thing.After checking everthing without any luck the battery went dead.Had it checked and it had a dead cell.Put in new battery last fall,car ran great.Stored car thru winter,started driving it again in April.Today I'm running through the gears and after about 15 miles it died again.Started immediately,died again after about two blocks,startede again and drove it home,about two miles.I'm thinking it must be an ignition problem but don't know where to start.It could be a bad coil,shorted wire,grounded wire.I do have a shop manual and some test equipment to work with.
Ray

 

check fuel pressure...

any codes?

 

This one is way out of the possibilities, if your alternator’s diodes fail, this sometime will not charge the battery, kill the ignition, change the radio station, and other weird electrical occurrences. This can all happen while the volts read good, but it is not DC without the diodes.

Most likely it will be something else like the ignition module, coil or something else of that nature.

The diodes can be checked if you took your car to a parts store and had the alternator tested.

 

How many key's do you have on your ign key ring.
Just a thought!
Is the gas tank full?
Are the battery connections tight?
Is your air filter clean?
Did it overheat?
Is the fuel pump wiring plugged in good at the tank.
What did you do the car lately that may have caused this problem.
Usualy a dioad will kill the battery over a few day's.

 

Check your fuel pressure. Could be a clogged fuel filter, fuel regulator or your fuel pump, etc.

 

i had a similar problem with my 88 and it turned out to be one of two things. since i replace two items at one time it is a little tough to tell but, i replaced the ignition control module under the distributor cap as well as the spark control module. on the 88 it is to the left (passenger side) of the heater core housing seemingly outside of the engine compartment near the hinges of the passenger door. i tapped on it while the engine was running and the car died. both are inexpensive.

 

I would suspect a ignition problem. The coil, ICM and ECM are items of consideration. I would put the coil last at this time as suspect. The ICM is a know problem to cause these classic intermittent problems because it is a solid state device and runs hot. Substitution is the only real check in your situation.

The ECM has caused some problems and actually checking it for the drive pulse to the ICM is a simple thing to do.

My only other thought is the fuel pump cutting out. Do you remember if you were low on fuel (1/4 or less) when this happened. With an older pump, if you don’t keep it cool with enough fuel in the tank, it might run warmer and quit.

I don’t think if the battery and alternator is going to cause this problem. If you lost a diode in the alternator, it just would not be able to put out full current capability but would be probably able to produce normal voltage. Even if the alternator quit you could run on the battery for a while, but would not get it started again. Takes much less to run than to start. Never heard of a battery causing a car to quit while it running at cruse. Probably would not be able start it if it was that bad.

The key is to diagnose the problem in the non-running condition, if it running you will likely find nothing.

 

I would check fuel pressure first as stated above. See where your at with that, but I'm leaning towards a spark issue....more or less a bad connection.