When the outside air temp reaches above 70 degrees, my Blazer will die going down the road. It will not start for about five minutes, then starts up again. Also, I have took the overflow cap off, poured water in it, and it would start up fine. I don’t know what is causing the problem, it runs great in fall/winter, but when it warms up, it starts doing this, please help!
I am thinking that the igniter module or the Crank Positon Sensor has become heat sensetive.
To trouble shoot the ignition system, carry a spare spark plug in the Blazer. When the engine will not start, disconnect one of the spark plug wires; connect the spare spark plug and lay it on a good ground point; and crank the engine to see if you have a spark. This rquires two people one to crank and one to watch.
There is a electrical tool that you can connect between the spark plug wire and the spark plug in place in the engine that will flash when there is spark current flowing. This could possibly be a one person trouble shoot if you can visualize the neon tube from inside the truck.
Hope this helps.
Without the benefit of any type of inspection I will comment that the fuel pumps in all GM vehicles (exclude the Corvette, never had to do one of them) were a very weak link in the reliability of these cars. How about it, are you still on the original pump? I have seen these cars towed in, and then you go to bring the car in the shop (expecting to push it) and they start right up and you drive them in, but if you drive the car long enough it will fail. These are one group of cars/trucks that you do not return to the customer with “could not duplicate” on the repair order. If the customer says the car dies, you treat it as if it really does die, even if you do not drive it enough for it to die on you.