1967 Camaro with starter problem

[Doug]

I got a 67 Camaro that when it's been driven and gotten hot the key will not turn the engine over. I've got a jumper wire on it now that goes direct from the battery to the starter which turns it over without a problem plus I've got a new starter on the car so it's not the starter. I've also replaced the keyed ignition in the dash. Does anyone know if there is any kind of thermal safety switch or other type of switch that would prevent it from turning over when it's hot??

thanks

[JohnZ]

The purple wire from the ignition switch goes to the "S" terminal on the solenoid to energize the starter; somewhere that circuit has high resistance and isn't delivering a full 12 volts to the "S" terminal. If it's an automatic, check the contacts in the neutral safety switch. If it's a manual OR an automatic, check the terminals in the inboard multiple connector on the engine compartment side of the fuse block for the purple wire. There are no thermal switches in that circuit - it just runs from the back of the ignition switch, through the fuse block connectors, to the solenoid.

[Doug]

I checked the purple waire last and you're right. I found that I'm only getting around 7.5 volts. I'm also having issues with the fuel gauge as well and noticed that I'm getting around the same voltage from the wire coming from the gauge to the sending unit. Any chance that the voltage regulator may paly a part in this? I checked the neutral safety switch a few months back and that didn't seem to be the problem. Thanks for your help.

[rich69rs]

Doug -

From your original post, I assume that this issue does not occur all of the time, that it is a "hot start" problem, and that the car starts and runs "ok" when cold.  If this is the case, heat is most probably part of the problem and it is somehow affecting the ignition wiring and / or the battery cables and the starter / solenoid.

Wiring of all types used in our rides will exhibit increasing resistance with temperature.    Increased resistance leads directly to lowered voltage.  This is true for the battery cables, starter, and the solenoid.  A potential source is excessive exhaust heat.  Problem is even more aggrevated if the wiring (battery cables are a good example) is in any way damaged, i.e. cracked insulation, fraying, etc. 

Starter and excessive exhaust heat (especially from headers) has been recognized for a long time as leading to hot start problems.  Same basic issue - too much heat increasing the resistance in the starter's electrical circuit.

If your battery cables are not pristine, you might consider replacing them.  If you have exhaust headers / pipes running too close to the starter, you might consider installing a starter heat shield.

Keep us posted on your progress.

[carnut]

Do  volage drop tests on all the battery and starter cables. Main cables should have no more than  about .2 volts drop. Any Automotive textbook should show you how to do a voltage drop test.
                                                                    Rob.

[Doug]

Thanks Rob, I'll give it a try and keep everyone posted

[CL8N]

I have a simliar problem. On cold start ups my car seems to do okay. (Maybe takes a few turns to start but it's at least turning over) I've had the alternator and battery both checked and they're fine, but after driving for a while, if I shut the car off and try to start it back up without letting it cool down for a little bit, it won't even turn over. I have a heat shield on my starter, but I'm lost to what's causing this problem.

[Oregonjam]

if I shut the car off and try to start it back up without letting it cool down for a little bit, it won't even turn over. I have a heat shield on my starter,

CL8ON-
If you have headers the increased heat can seriously change the performance of your starter solenoid. Depending on your headers a heat shield may not be enough. The next step is a mini-starter that can swing out of the way and provide more distance from the headers.

If after the engine is hot and the starter turns over but it still can not start, you may be seeing vapor lock. The fuel lines and/or carb are getting too hot and the fuel vaporizes before getting thru the carb. To fix this, pick up a carb heat shield to help deflect the heat away from the carb. Also check to make sure that no heater hoses are contacting the fuel line from the fuel pump. That seems to be a commonly overlooked problem and easy to fix by installing the proper length heater hoses.