99 blazer wont start after rain or too hot and humid

[ctla4]

Hey, maybe someone can help, I have a 99 blazer 2wd, 73000 miles. When I drive on rain or very hot and humid, stop and then return about one or two hours later, the truck wont start. It will crank, lights will be on, dash on and radio on, but no start. I'll try to start it every 30 min or so, and all lights on, full crank but no start. Then 2 or 3 hours later, starts like nothing ever happened. I took it to dealer, they put it on the computer but no codes came up. Can anyone tell me where to start looking?
Thank you!

[BlazerLT]

change you cap and rotor.

Don't change one or the other, change both.
time for a tuneup including....

Air Filter
Fuel Filter
Spark Plugs (Ac Delco preferred with proper gap set)
Cap & Rotor

[metallica21156]

try the MAP sensor. just had it changed on my parents truck. it was a 98. as soon as it would rain it wouldn't start. we played with it for a while and finally got it to start and then shut it off and it wouldn't start again. changed sensor and works fine now. before changing that we did a complete tune up.replaced the disturbuter, had a crack in it.

[BlazerLT]

Wouldn't it be smart to do proper maintenance first with a tuneup before replacing random sensors?

Not challenging you, just being logical.

[Mikado14]

I have a question----- What made you go to the MAP sensor? What diagnostics did you do? Just curious.

[metallica21156]

don't know. installed at a shop. i'm guessing OEM. no codes were read on the computer.

[BlazerLT]

I had a rough idle and I reseated the connectors on the computer on the passenger side wheel well and all is great now!

If the engine computer grounds are iffy, the whole engine won't run properly.

Reseat your computer connections. All 3 or 4 of them.

[metallica21156]

mine ran fine once it was started. it was getting it to that state. well opened the computer shell and found out some water got in that as well so you might want to reseal that. i have a 95 blazer and i've never had any problems with the computer so i'm not touching it.

[BlazerLT]

I had an oil pressure gauge that liked to twitch every once in a while and the idle was really bad.

Once I reseated the connectors, everything has been great.

[metallica21156]

well then if everythings fine then i wouldn't worry about it.

[BlazerLT]

You notice the thread starter has not responded?

How lame.

[ctla4]

Thank you for all the answers, Im going to do the tune up recommended by BlazerLT, this week, then i'll post results.

thanks again.

[BlazerLT]

Originally Posted by ctla4

Thank you for all the answers, Im going to do the tune up recommended by BlazerLT, this week, then i'll post results.

thanks again.

Also, use the right AC Delco plugs and gap them properly.

Don't use Bosch platinums.

Do a complete tuneup.

[Rick Norwood]

I agree with the tune-up logic, but doesn't a faulty Map sensor show up as a code?

[metallica21156]

it never set off the code. it never had a problem when it was running. if it would have it might have triped it.