Engine sometimes dies when signal & radio on.

[kensmith]

I have a 1978 124 Spider all stock. two days ago I was checking the timing and the motor was warmed up. I used a second battery for the timing light. All was fine until I disconnected the timing light from #1 spark plug wire. The car dies for no reason I can think of. I waited a few minutes and it started right up. Then today, I warmed up the motor, turned the stereo on and was listening to music. I thought I would check the turn signals so I hit the left, it worked and then the right and it worked and then the motor died again. It started right back up so I went for a 60 minute drive and used the signals and all was fine. I must have something causing a short somewhere? Ideas on what's going on?

[kensmith]

Nobody has any ideas why this happens?

[RoyBatty]

Hi Ken,
Is the heavy bonding cable under the drivers side of the car connected to the bell housing fasteners or starter mount fasteners?
It sounds as if you are having the electrical load of those items draw power from the ignition. Make sure all grounds are clean and secure to start with. We really do need to get together with Spidernut one of these days.
How about a Memorial day short meet up?

[kensmith]

Hi Ken,
Is the heavy bonding cable under the drivers side of the car connected to the bell housing fasteners or starter mount fasteners?
It sounds as if you are having the electrical load of those items draw power from the ignition. Make sure all grounds are clean and secure to start with. We really do need to get together with Spidernut one of these days.
How about a Memorial day short meet up?

Hi Roy,

Can't this weekend as I have guests visiting but maybe in the next few weeks? I also need to get this electrical issue fixed so I don't get stranded somewhere. So far it hasn't died while driving the car. Only while idling in the garage. There are so many disconnected wires on this car that seem to go nowhere and you never know what the prior owner has done.

[racydave]

I thing the engine ground cable is something to look at. Alot of us have added another cable from the engine to the chassis for weird problems. Also, I have heard of carbs getting loose and causing idle problems, keep her runnin, and grab the carb and wiggle it. If not, a volt meter at the idle solenoid or 12v feed to the dizzy might help diagnosis??? Another free check is in the connector at the base of the steering colum, as some wires tend to get hot and burn the connector.

[kensmith]

I thing the engine ground cable is something to look at. Alot of us have added another cable from the engine to the chassis for weird problems. Also, I have heard of carbs getting loose and causing idle problems, keep her runnin, and grab the carb and wiggle it. If not, a volt meter at the idle solenoid or 12v feed to the dizzy might help diagnosis??? Another free check is in the connector at the base of the steering colum, as some wires tend to get hot and burn the connector.

Carb is good, ground is good, I'll check voltage next. Possibly an alternator issue at low RPM? I can't for the life of me figure out the engine dying when I removed the timing light. I had the timing light on a separate battery, removed the timing light + and - cables from the second battery and all was ok. But when I removed the clamp to the number 1 plug wire, the motor died. It would not restart right away and 30 seconds later I saw the CD player cycle like the battery was removed and re-installed. Makes no sense to me.

Then the next time it happened the car was idling, I had the radio on and checking the turn signal switch and it dies but started right back up.

[racydave]

Not a alternator issue, as it merely keeps the Battery charged. Sounds like a issue with poor connections at the battery. Or battery ground at the chassis. Maybe poor connection at the startes, as this is a junction for power distribution.

[kensmith]

Not a alternator issue, as it merely keeps the Battery charged. Sounds like a issue with poor connections at the battery. Or battery ground at the chassis. Maybe poor connection at the startes, as this is a junction for power distribution.

Usually a poor ground at the battery or the chassis will be heard through the radio as a hiss or wine. I will re-check those connections. I have a feeling this is going to be a difficult to find problem. These cars are old and lots of people have worked on them. Hard to tell what they have done or left undone.

[kensmith]

Not a alternator issue, as it merely keeps the Battery charged. Sounds like a issue with poor connections at the battery. Or battery ground at the chassis. Maybe poor connection at the startes, as this is a junction for power distribution.

Checked the battery ground, ground at chassis, some minor corrosion but all nice and tight. Has not died again so not sure what's going on. I am going to check the under dash wires again near the steering column.