electrical problem with my 65 Mustang convertible

[joeyemma]

Hi...I have a 65 green Mustang that I store in a garage in NH over the winter. Picked it up yesterday. Had to jump it....no problem, I expected that. Let it run for a while to charge the battery back up and it did the trick and started right up several times and ran like a charm. I drove it home (over 100 miles) with several stops along the way. No problems with the car...ran great and started back up easily every time I had to stop.

After about 150 miles of driving I noticed it running a "bit rough" but no problem. I parked it in my driveway and 1 hour later went to start it...dead. Turned over slightly but not even close to starting. Took the jump but would not re-start again so it is not holding the charge now.

This happened to me last summer and I replaced the battery and the alternator and the problem was solved. Belts look fine.

The engine is recently rebuilt.

I don't dare take it out today (even though it is gorgeous out) because last summer when this happened I got stuck 30 miles from home and it would take a jump, but would not continue to run as the alternator was shot.

HELP.....I am going to take it into my mechanic on Monday but if there is anything I can do myself today I would love to try.

Thanks!

[OsirisGuy]

It kind of sounds like the alternator again. Do you have a multimeter? I'd check the battery voltage and then the voltage at the alternator, the alternator should have a higher voltage (< 1 volt) then the battery. You can also try and unplug the battery as the car is running and see if the car still runs...

Although I do not know how well these things will work on the older cars, especially running the car on the alternator alone, I know a lot of guys here (I believe) do not like this test.

[joeyemma]

ok....this is what is going on now. I put the new battery in and it was fully charged. The car still required a jump to get started. I don't understand that. But then it ran great. Perfect...smooth and strong. After about 20 minutes it started to muck down again....sputter and not idle properly. And when it did finally stall, it would not start without a jump. I am hoping to get it to my mechanic tomorrow....just don't understand what is going on.

[OsirisGuy]

I'd say again, check the battery and alternator with a mulitmeter. Look for any electrical shorts in the car especially if any work has been done to it.

However have you considered that it might not be an electrical problem? Perhaps a fuel delivery system malfunction?