Car doesn't start in the heat.

Ok, so here's what I know.

- I get up and go to work at 5am (fairly cool outside) car starts fine
- I leave the car sitting in the heat outside work ( 90+ degrees)
- I go outside to leave... unlock the car, turn the key and CLICK.... nothing. -- The lights and all in dash display goes off like the battery is dead, but the motor isn't able to turn over due to power loss.
- If I go disconnect the positive and negative terminals, and then reconnect...BAM the car starts fine.

Here's what I've checked.
- Corrosion on battery
- lead grounds
- Also, when I put my key on acc, my voltmeter reads power at 12.5v which is plenty to start'er up.

I have no ideas. I'm lost. Anything would be great. My logic tells me that the heat has something to do with it, because this only happens after the car is sitting in the heat or is hot. It hasn't happened once when it's cool.

no CEL? ... my girl's sister had a similar problem ... threw a eng. coolant temp sensor CEL ... i don't understand it but it turned out she had a bad battery ... so i think you should take it to your local autoparts and have it checked properly, they check it under under load and junk ... if all fails, check that eng. coolant temp sensor

Could it be the innards of the starter? Perhaps the solenoids are tired?

Possibly a problem with the main relay?

Doesn't sound like a main relay.

the car will still crank with a faulty main relay.

you could have an electrical leak.
batt cable might have a short in it.

dadams said:

you could have an electrical leak.
batt cable might have a short in it.

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parasitic drain.

disconnecting and reconnecting the neg bat cable wouldnt recharge the bat

you should try changing the main fuel pump relay and clean up your battery terminals.

ZsleepizeZ said:

you should try changing the main fuel pump relay and clean up your battery terminals.

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Changed the fuel relay last year. Cleaned the terminals last week to no avail