Quirky electric puzzle

[Parker]

I bought a '73 2.0 and I love it. However, it's been frustrating me on occasion when it doesn't start (imagine that). It's happened three times. I'll try to describe the circumstances. Please help me troubleshoot this problem.

1. Doesn't start = turn the key, engine doesn't turn. Deathly silent, except for the fan? I can hear spinning up.

2. Jump starts work. Both battery and push methods.

3. It does not die while running. Drove it from LA to San Diego last weekend--no issues. However when I got back home after two hours of driving, right after I turned it off, I tried to re-start it. Dead. Two days later it started on the first turn--no battery charge or anything.

4. It has only happened after I've been driving it for at least a half hour. When it sits, cold, in my garage it starts like a charm.

Investigated causes:

Battery? The first time it happened, I recharged the battery. It took 5 minutes on a 6-hour charger to completely charge. the next incident happend after about one hour of driving time.

Alternator? I don't think so. Ran for at least three hours over the weekend. No dimming lights, no starting problems until I got home.

Bad ignition switch? The lights and other stuff turn on with the key, but it sometimes just doesn't start the car.

Does anyone have any idea what I should investigate next?
Thanks a million.

[SteveStromberg]

Ground Strap, try cleanig it up on the tranny to the chassis strap. or get a #4 battery lead and run it from the battery to the block.Steve

[BenI]

I experienced these exact symptoms with my '74 914. It just got more and more confusing-was it heat related? why do jump starts seem to help? Also, who wants to drive a car when you know it probably wont start when you get to your destination. I added a hot start relay, new ignition switch, checked the battery and all leads, cleaned the tranny ground...Finally I removed the starter and played with it. Turned out there were dead spots where the brushes made contact. I could never make a good arguement to why heat seemed to worsen the problem, except that heat increases resistance and maybe that was exacerbating the problem. Anyway, with the starter on the floor, i found that depending on where it stopped rotating I could get it to start again without rotating the gear a little bit. Bought a high torque starter, had the flange screws come out and it ate my flywheel. Bought a Bosche rebuilt starter-it too had dead spots. Finally I bought a Bosch starter that had been rebuilt by some american company and it has not given me any trouble for over a year now. I hope this helps.

Ben

[Eat-um-up]

My car does that. It does it due to a bad battery, and my cable connection. my battery is bad so it dont hold much of a charge. However if i reconnect the positive cable good and tight it works. you m,ight also want to look at the cable ends to make sure thier not being ate though by acid

[karlp]

I had very a very similar problem. Car would always start in the morning, usually get me home for lunch, would never start after lunch. I ended up leaving it on charge during lunch all the time, then getting a jump at work. Slowly got worse and worse.
Last straw was when I went to rescue my wife and her car. We had to leave hers there for a while and come home in mine. After we stopped for gas, she did not appreciate pushing me across the parking lot to get it running.
That night we took the starter off and took it apart. I found that the linkage that the solenoid pushes was binding. cleaned it all up, filed off some sharp edges, a touch of gear lube, and it hasn't missed a lick since.

[Dave at Pelican Parts]

See also:
http://www.pelicanparts.com/techarticles/mult_starter_diag/mult_starter_diag.htm

--DD

[Jim Smolka]

Could be the switch or the seat belt relay (74-76 cars [thanks DD]).

When the car does not start there is an easy test. On the engine relay board, remove the top plastic piece of the T-12 wire connector (wires closest to the trunk [see Haynes Manual]), you should see a yellow wire that goes to the starter. There should also be a large red wire there too. Take a small jumper wire and briefly touch the red wire to the yellow wire. If the starter starts, then the problem is fwd of the relay board (i.e. starter is OK)

Good luck.

[Dave at Pelican Parts]

There shouldn't be a seat belt relay on a 73, those were a 74 (and some 75) item.

--DD

[wilco]

Sounds like the solenoid. I have had a number of cars that were getting on in mileage and all at one time or another had the same problem. Until I could get the starter out and free everything up I carried a small hammer and gave the starter body a small hit whenever the problem occurred.
Ultimately easier to overhaul your starter as the other method gets tedious when its wet, dark, muddy, snow or whatever you happened to have stopped on. Hills are always useful.
Good luck

[WOODPIE]

Hello

I would bet on the solenoid, too. And the hammer thing. Been there, am still (occasionally) doing that. Especially when the engine is hot after a long drive.

Ed