85 chevy silverado wont crank sometimes

this is my husbands truck its a 85 chevy silverado pickup .it has a rebuilt 350 motor in it.the problem is when he go's to the store and turn the truck off and comes back to the truck after a few mins,and tries to start it .it wont start .we had the battery tested and its fine i think the alternator is ok on it,but when you hook it up to another car with some jumper cables the truck starts right up with no problem .my husbands knows alot about trucks but this one stumps him and would like someone's opinon on this.he's tryed every thing.he even played with the wires to see if there was a short and the gauge dident move so please help.thank you:screwy:

check for overfueling issues. chevys do that. (e.g. 800cfm aftermarket carb on a mostly stock 350)
then check the ignition system. ICM's go out sometimes/ get worn out.
check wires and plugs.
seems like it could be any of those.
flooding goes away after several minutes
OR the extra voltage is what the system needs to start.
oh and check the battery.
even if it's new, make sure the cold cranking amp rating is high enough to turn over that motor. i had a similar problem then i got an HEI ignition, new plugs, new wires, and one of those optima '6-packs' and it fires right up. except in the cold, but that's another story.

I agree on a possible weak battery condition. Make sure it has enough water in it first. My rule of thumb is, if the battery is more than 4 years old, chuck it at the first sign of trouble. If you got it used and have no idea how old the battery is, chuck it.

Also clean up all the battery connections and the battery itself. Get a charging/starting system check done before you buy a battery, most auto centers do them for a small fee.

Bob

I'm assuming you checked (and cleaned) the battery terminals? If they're corroded, wiggling them (as if connecting jumper cables) will often times improve the connection enough to let it start. If it's still got the factory side-posts, they can look ok outside but be blue-green inside. Pull them off to be sure.

First check to see if it has spark when it won't start. If not, it's probably a bad coil. Sometimes they won't restart hot.

It could also be the starter absorbing too much heat from the exhaust pipe... not an uncommon problem if the heat shield's rusted off

thanks for that info some of what you said could more than likley be it.i thought the coil but im a woman what do i know?..he drove the truck to work to day and went inside the store and it wouldent start it only clicked ,the battery is almost a year old and tested fine.but he jumped it off and it ran like a top again.only this small stupid problem.

then for sure check that coil and ignition control module out.

i didn't even think of that starter thing but he's 100% right.