my aunt has a late 80s, early 90's pontiac. doesnt turn on after driving for about 10 minutes.. why?

Question

ok.. so ive borrowed this once or twice and it works fine. it doesnt overheat or anything. but after i park it and turn it off for a bit, it wont turn back on for about 3 hours. does anyone know the reason.

Answer 1

OK, I'm convinced that these people don't have much experience working on cars judging from their answers. Run it for a while. Park it and turn it off. When it won't start, shoot some starting fluid into the intake. If it doesn't fire up, (going on the fact that you have to let it cool down) I'd say that the coil is bad. If it does start, first change the fuel filter. Then change the fuel pump if the problem persists. If the coil doesn't fix your problem (which I think it will) keep checking the ignition system.

Answer 2

More info please. Year, model and engine size would really help.

Check for fuel pressure while cranking (or listen for the fuel pump in the tank) then check if the injector is spraying (throttle body only). Then check for spark (put a spark plug in the wire end and lay it on a metal part of the engine don't touch but look for a spark).
If there isn't any fuel pressure - Faulty fuel pump relay or pump overheating and quitting.
If there is fuel pressure but no injector spray - No signal from ignition module to the computer for injector pulses.
If there is fuel spray but no spark - Faulty crank or cam position sensor or faulty ignition module (they will quit when hot then work after cooling off)

Answer 3

Does it crank? then start after long periods of cranking? This could be a fuel pump relay going bad. A weak fuel pump will do the same or even a clogged fuel filter or clogged screen at the fuel pump. Vapor lock is also a possibilty if it is a carbuerator.

Answer 4

Bad Fuel Pump

Been there done that i had a 89 chevy celebrity (yeah my parents hated me lol) and it did the EXACT same thing!