I was wondering if somebody could help me with a little problem. My 91 Camaro TPI automatic dies whenever I drive for prolongued periods of time (more than an hour) on very hot days (mostly between noon and 6 pm; in the Los Angeles area the temperature is usually over 100 F either going uphill or travelling very slowly while in heavy traffic. Last week I traveled from Los Angeles to Los Vegas and my car sputtered a little bit and died whenever climbing the very steep hill under the noon sun. Whenever this happens I have to wait for about five minutes and the car will start again. If I keep going uphill it will carry me for about three miles and will die again. As soon as I get to the top of the hill everyhting is O K. The car goes down no problem. It does the same when stuck in traffic for prolongued periods of time. For some reason, the heat of the day seems to be a factor. Traveling on the hill during the night the car is O K. I was told that the fuel ump is overheating. It must be a fuel problem because the car dies as if it runs out of gas. The funny thing is that I can always re-start it as long as I let it cool down enough time. At night it seldom does it. So far it has happenned about twenty times and I have been lucky to survive a few incidents while traveling in some of the busiest LA freeways. Now the fuel pump is one year old and I have a new fuel filter. Why is it overheating?. Or is it something else. I can hear the fuel pump in the background. When it is about to die it makes a high pitch sound as if the amperage on the fuel pump is increasing and then dies. Somebody also told me that it could be vapor lock. If so, how can I make sure it is vapor lock and how to solve it. Could I have a bad relay that disconnects whenever the engine compartment is too hot?. Any suggestions?. The engine does not overheat at all. I changed the water pump two weeks ago with one of the high performance ones and installed a 160 thermostat. I just don't want my car to overheat in heavy traffic. So the engine is always cool. I was thinking it could be a sensor that might be shuting down the fuel pump but I don't think so. Some mechanic told me that this is a common problem on Chevy cars. If so, could somebody explain to me how does a fuel pump overheat while it is inside a full fuel tank cooled down by the gas?. Thank you very much.

 

Get a fuel pressure gage and find out for sure what is happening.

Most likely you'll find the pressure is low even when cool and the engine appears to be fine, but drops too low when it stops running.

If it isn't fuel, you don't want to find that out after replacing the pump. The cost of the fuel pressure gage is certainly worth that.

 

My guess is vapor locked fuel also. Happens to my car once or twice a summer.