My 90 RS won't start after it gets hot. So i bought the car last summer and as a project and ive never really ran on the road because it has bad tires and it hasnt had inspection or registration since 2005. This past week week i left it running for the battery to charge for about 20-30 min and while i was eating dinner all of a sudden it shut off i went outside to check if some one had went to turn it off but nope. The fan was still running and temperature was normal, right in the middle i believe its 220°F i checked gas and it still had some some so i tried turning it and nothing. Next day after i got home i tried turning it and it turned right up battery had recharged and was running good again. Please help me!! This is supposed to be my car after i graduate from high school this summer.

 

Fan relay is sticking. I highly doubt it recharged on its own tho.

 

Ive read it could be the ICM that doesnt work when hot but it not only didnt want to start it also turned off on its own but idk. What do you mean you doubt it charged on its own?

 

you need to find out if you are losing fuel flow or spark when the engine stops without being switched off-next time this happens,take the air cleaner lid off and see if fuel is sprayed while cranking-if no fuel,pour a little gas down the TBIs and see if it runs for a moment on the poured gas.If gas is present when engine stops,likely spark has cut out-bad ICM or distributor not getting power because of bad connection the most likely cause,bad pickup coil is also possible but that is rare.For no fuel,bad fuel pump,faulty ECM,or a bad connection cutting power to ECM, injectors,or fuel pump,could be the cause.Could check if there are any stored fault codes too.

 

Batteries don't charge themselves without being plugged into a charger or having the alternator turning with the motor running. The relay sticking was common tho.

 

What well it was actually the longest time I've had it turned on for since I've had because I was tired of jumping it everytime I wanted to move it out of the garage and yeah the car was on battery did charge because the next day it started cranking like normal and it turned on too. But on fuel sometimes it is bad and it will just crank and crank but not start I wonder if the ICM causes that too but idk

 

You might want to check the resistance on your injectors. The coils have a tendency to fail when they are hot. It's a common problem with the stock injectors

 

Sorry for not replying but idk what it could be. Just yesterday I took it out for a spin and I floored it all the way to about 70mph in the neighborhood and then when I slowed down and turned around I was pressing the trying to accelerate and it just wouldn't go it almost died on me but then all of a sudden it was working again and I drive it back home and put it in the garage idk what it could be that causes all these problems but I sure hope to fix them by April our May

 

Why don't you check the codes? You absolutely need to start at the basics, fuel and spark...these are both computer controlled.

now if I can just figure out how to post an upside down question mark...

 

For that do i use the OBD scanners? By the way i'll put one so youcan copy it lol ¿?¿

 

Hey how did you make out? sorry I have been sick like a dog and kinda forgot about this thred. Oh there is a bunch of expensive, cheap, good and bad OBD 1 scanners out there, for the hobbyist I would recommend some of the cheap laptop software, that gives codes and live data basics. More complex software is over kill if your not a tech with a fair bit of knowledge...

Easy way is just jumping the A/B terminal on your diagnostic connector and counting the flashes, then report back.

Thanks ¿¿¿¿

 

O nah dude that's alright but me and my dad were hoping on buying the orange one they sell at auto zone it's a OBD I and II. It cost like $200+ but how do you do that with the terminals is some video on you tube I could use?

 

You can pull codes with a paperclip. Bend it so the two ends are almost next to eachother and then stick them in the upper right two terminals of the DLC (connector under the column) and watch the check engine light flash. it will flash 12 three times, then any codes it has set, each three times, and then 12 again to let you know its done. Example, for 23 you will get _ _ _ _ _, _ _ _ _ _, _ _ _ _ _.

 

Any OBDI scanner will work as long as it has the 12 pin GM ALDL connector. This diagnostic connector and most of the scan tools and vehicles that used it are long since obsolete. That means you can find them cheap used on ebay or craigslist.

My first suspicion would be the ICM. However, don't think that if the ICM is failing you will only lose spark. Depending on what part of the ICM is failing, you may lose spark and injector pulse. The pick up coil will also cause you to lose both and if your distributor is original, failure of the pick up coil is not unlikely.

To test your injectors, use an ohmeter and test them first cold then again hot. They should read about 2.2 ohms cold, 2.4 hot. If they are much less than 2 ohms or if the resistance drops when hot, send them in for bench testing.