I read in my manual that the service engine light comes on for emissions stuff so I figured this would be the place to ask.

My check engine light comes on when I'm decelerating from above 40, but only while car is reletively cool. Any ideas?

 

Id say its something to do with your A.I.R., or smog pump. Thats when it kicks it to inject air to your cylinders and cats......Take the hoses off of your pump and rev up the motor and see if its pumping out air....Youll know if its good or bad from there.....Good luck.

 

Go buy a scanner or jumper the aldl connector so you can read the trouble codes.. that code should be stored in there and that will give you the best place to start..

 

The AIR pump does not have any thing to do with this problem AIR doesn't have any diagnostics codes or otherwise. The ECM controls the operation of the system that's it. I've had my AIR completely removed for 3 mos. now with no adverse effects the engine bay is prettier though. I agree with J'S T/A get the car scanned any one owning one of these old beasts definitely needs diagnostic capabilities. Good luck.

Mike

 

IF the pump is not functioning correctly when de-accelerating...it will throw a code...that happened to me before. Maybe its different on his car..or yours. Mine threw a code when I took off my AIR pump and equipment. But, mine is a 91 Z with dual cats...so maybe mine is setup different. Thats really the only code it could be.....

 

What was the code #?? i have the dual cat setup also and haven't heard of a smog related code.

 

It had a code 61 in it right after I took off the AIR stuff....well about a week later I guess...if you jumpered the plug that goes into the pump, it would go off.....I know code 61 is for a contaminated 02 sensor....but it was new....so maybe it was a glitch. I have heard of people taking it off and not having any codes....but Ive also heard of people having them. So maybe its something else going on.....not sure. I stand corrected I guess....I apologize.

 

Yeah it looks like they did remove some ALDL circuitry in 92. Maybe GM was trying to figure out what a waste AIR was on the car and just didn't have the gonads to remove it. But mine doesn't diagnose it as I said 3 or so mos and not a whimper.

 

ahheeahhh 02 sensor and AIR pump are almost 2 different worlds.. I have never heard of removing the AIR pump and getting a AIR related code.... the 02 sensor was probably getting jammed up with unburned fuel cause the engine wasnt heating up as fast as it would with the AIR system. SES lights do not always mean smog problems. If your MAF goes, its not gunna fail you in inspection. Scan for the code and come back to tell us what it is. You can do it with a paper clip.. very simple... there is a tech article on it, or you can PM me and i will let you know how to do it. good luck.
Alex

 

Yeah the paper clip is a good idea....dont know why I didnt think of that before.....that would be the easiest way to find out what it is.....Like I said before I guess mine was a glitch.....I just assumed it was that because it happened so close to when I took all the smog stuff off.....my fault. I dont have to worry about the MAF thank ***....Im speed density..