Hello,

I have a 1992 Camaro RS 305 auto and am having an issue with my check engine light coming on. I have noticed that upon startup, it is never on. It usually comes on after the car has warmed up and I'm coming slowing down from higher speeds. I have gone long distances on the highway without it coming on, but as soon as I slow down, it will come on. After I turn the car off and back on, the light is no longer on.

I also took it to O'Reillys to have them scan it, but it isn't throwing a code.
Somebody help please.

 

As far as I know O Reilly's will only check OBDII codes and you have an OBDI system. You need to take a paper clip and jump the top right 2 ports on your OBDI plug, then turn your key on and watch the light show.

 

I'm actually having the exact same issue with my 91 rs 305 5 speed. I had my friend try to read the code with his reader n we got nothing. I was thinking about swapping the stock computer for a ebl flash cuz it will take engine mods better and I've been having problems with the the anti-theft system.

 

You don't need a reader for OBDI, just a small piece of wire or a paper clip lol

 

I don't think its storing the code. Because the light is always off when I start the car then comes on after its run for a bit. I don't know if that would make it where we cant read it at all or not.

 

should store. disconnect the battery for a minute to clear all codes. search here for codes. I recall 3 blinks is start of read code followed by the error codes. ends with 3 blinks. When I last did that 5 years ago I had my wife write down pattern of blinks as I flipped key on. I had two codes to follow.

 

the code wasn't storing, that was my problem. O'reillys had an OBDI connector and used their scanner to check it. at first it said it was retrieving a code, then it stopped and said no codes were stored.
i don't care too much about the check engine light being on, i just would like to figure out if there's any real problem. does anyone have any idea on a cause for it?

 

The SES needs to be on for a period of time before the ECM will store the code (about 20 seconds). If it was on from the time of decel until you did a key-off there should be a code stored.

Try the code blink: short A& B on the ALDL connector, key-on, engine-off. First code will be 12, three times. Then the next code in line.

It may be that it is an EGR failure. GM usually tests the EGR functionality during decel.

RBob.