Electrical System Disaster

I have a 1969 Impala, and there is a problem when I start it sometimes. I have a water temperature gauge, and between the 100 and 150 degree range, she won't start. If the temp is higher than 150 or pegged on the low end, she will start just fine. When she doesn't start, there is no clicking or anything, it just won't start. The GEN and HOT lights are on, but no start. If I go to jump the car, everything is fine, she jump no problem. Also when I am driving, when the turn signals are on, or I apply the breaks, the voltage gauge drops slightly off of 14 volts. Not sure if that has to do with this electrical problem but it may be related.

Thanks

I don't know why the gauge would only act up in a certain temperature range, but if jumping it helps then there might be a short inside the gauge or something. You might want to try replacing the gauge.

When you hit the brakes, I don't think the voltage should taper off, but 14 volts doesn't sound that bad. How old is your wiring? Is the alternator old? Are there alot of aftermarket electrical parts?

when you say it won't start, is the engine turning over, or do you just hear clicking?

I doubt the volt gauge readings have anything to do with the problem. IMO, you probably have a failing starter (from what info is here so far)

There is no clicking starter and solenoid are new. I have new battery wires,altenator,distributor the neutral safety switch is ok. When the temp is around 150 it will not start. Checking the battery with a meter shows 12.5 volts. When the car cool it will start. I also wrapped starter to keep heat off of it from headers.

If its turning over, perhaps there's a problem with the carb or distributor that comes out in that heat range. Is it tuned properly? Maybe the timing advance is off a bit?

well, you've replaced everything but the ignition switch....and harness

Need to put a volt meter on it, and trace power when it won't start. Only way you're going to narrow it down

This is an old car so the charging system acid test is safe to use. Once the car is running, remove the negative battery terminal, if it stalls out, it is NOT charging. Stop right there and get a charging system check.

Did you change the voltage regulator when you changed the alternator? Pre 1973 or so cars didn't have the combined units, unless yours was changed over.

Next, totally disconnect the temperature gage from wherever you got it tied in electrically. (Personally, I like mechanical temp gages.) Make sure no other wires under the dash are grounding out to it.

Bob