where do i look for this problem,car warms up on a hot day & sometimes wont start till it cools. Is this bad engine wiring harness or bad starter or both:confused: this happened to me in the middle of a cruise:sad: please help

I had that problem myself several years back, know how you feel. Could be the starter , but first I would try some other remedies which may be more likely.

If the starter wires become overheated for some reason such as close proximity to exhaust headers resistance in starter wiring causes a drop in supplied voltage to the starter and there is not sufficient juice to properly operate the starter. That is why the vehicle will usually start fine after a cooling off period.because the wires are producing sufficient voltage to operate the starter.
A remedy which often cures the problem is to install a Ford-type solenoid some place inside the engine compartment away from major heat, i.e., the inner fenderwell or firewall. This solenoid is placed between the battery and starter solenoid and when the ignition is turned on the remote solenoid gives the solenoid on the starter a higher than normal jolt which is often enough to overcome the resistance created by heat.
The Ford solenoid is not very expensive (approx. $25 or less) and can be found at most good auto parts stores. Jeg's and Summit also usually have them in kit form complete with all installation instructions fittings.

what if I just replaced the harness with new, plan on doing it down the road anyway. Oh, and it has stock manifolds

Egore just a little more info that sliipped my mind . You might also install a starter heat shield which may help your problem. If the situation persists after that and the starter and wiring are good I woud strongly consider the remote solenoid route. It cured my identical problem three years ago. I currently have a post about my starter problem, but don't think my remote solenoid is at fault. Worked fine yesterday.

where do i look for this problem,car warms up on a hot day & sometimes wont start till it cools. Is this bad engine wiring harness or bad starter or both:confused: this happened to me in the middle of a cruise:sad: please help

when it won't start, had it already been shut down and then tried to restart.... or did it die, and then an attempted restart? Last summer, while my car was idling, it would die a few times. Ended up being borderline vapor lock of the fuel. It wouldn't start again for a few hours.... just a thought. I wasn't sure if your's wouldn't start to begin with, or it had died....

Egore. just saw your reply. If your wiring harness is in question it could cause or contribute to your problem. nevertheless if it makes you more comfortable go ahead and replace the wiring. It may or may not cure the hotstart plague. Either way I highly recommend the F--- solenoid route. Inexpensive, easy to install, and often works great..Many, many on this forum have done so and had great sucess. Sure beats pulling up to a cruise-in swelling with pride for your great ride and then having the dreaded click, click, when you go to restart in front of all the other gearheads! Been there, done that.

The year and engine would help as well.

thanks, know I know where to start,gotta go to bed, i work in 4 hours.

I had the same problem on a Corvette, the heat shield solved it.

Once on a 69 I owned in the mid 80's, a automatic if that is what we are talking about, the wiring for the neutral safety switch would heat up and prevent start up. A quick fix with thicker gauge wire. You should be able to hold the wires in your hand, if you can't because they are too hot I would start there. Remember thicker gauge will fix all heat up problems.

the car is a 67 rs with a ( 283 came from 66 chevelle) auto powerglide.