redlines4us

My service engine light came on and when my mechanic put it on the computer he got code 23 (MAT sensor). The books do not show a MAT sensor on this car. It's a 1992 Buick Regal Gran Sport with a 3.8 Tune Port Injected engine. It has 80,000 original miles. The only sensor that it could be is the one that goes into the side of the air cleaner. Does anyone have any help or info on this sensor or trouble code? My local Buick dealer (not my mechanic) just ordered me the sensor that goes into the side of the air cleaner, but I'd like to know if that is the right part for trouble Code 23. Thanks! Bill

P.S. Does MAT stand for manifold air temperature?

tman

The one in the air cleaner is the mass air flow sensor. Wait until Flatrater comes around, he knows loads about the really technical and electrical issues of these cars.

BTW- I like that cutlass in your sig, I always liked Cutlass Convertables

redlines4us

tman2093,
Thanks for the response. I'll hope that (Flatrater) can shed some light on this problem for me.

By the way, thanks for the compliments on the Olds. It's for sale as we speak. I bought it for a work car and it's way to nice for that so I bought this Regal for work and am selling the Cutlass. Thanks again! Bill

tman

You said you had a mechanic run a diagnostic test, where you taking the car in for a check up, or was there a problem?

redlines4us

My "Service Engine Soon light" came on that's why he ran a diagnostic test. That's when he came up with Code 23 which is supposedly a MAT sensor problem.

I went to: http://www.troublecodes.net/GM/92-95_38L.shtml

Here's what they said about Code 23 for a 92 Regal with a 3.8 engine L body code:

"Code 23 - Inlet air temperature sensor signal showed an air temperature of -29° F for 4 seconds."


Is this the sensor that hooks into the side of the air cleaner?

pcv

Code 23 is Manifold air temperature code. Yes, replace the mat sensor if the readings were out of wack. Its on the air intake. Good Luck.

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Flatrater

Its been awhile since I worked on a car this old! The temp sensor for intake air is called the IAT. By any chance did the tech give you any info on what the scan data said for this parameter? Some techs call it by MAT which is a non GM name for it! Most of the time I see this code the sensor is unplugged. But I have done some wiring repairs also for this problem.

If the sensor is reading a very strange number like -40 degrees than the computer is seeing an open circuit and defaulting to the negative number. If you jumper the 2 wires together the sensor reading should go high! If it does than you have a bad sensor if not you have a broken wire.

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redlines4us

Thanks for the help guys. Here's the latest:

As I said, my local mechanic hooked up the car to his computer and it showed a #23 fault and he didn't mention anything about any readings being out of wack. But as I said there is no MAT sensor in the book for this car so he determined that it must be the sensor going into the side of the air cleaner. I changed out the air cleaner sensor with a new one (from Buick garage) and drove the car for a day and eventually the servce engine soon light came back on but it don't stay on all the time. It comes on and stays on for about a minute and then goes back off for awhile. Then later it comes back on them back off again. It never stays on full time!

Also, before any of this ever started, I noticed an odor coming from the exhaust. It almost smells like a car that's burning too rich smells. I thought it was possibly the catylitic converter plugging up, but had it checked (visually) and it looks to be fine.

Now my light still comes on once and a while but doesn't stay on, I have an odor coming from the exhaust that stinks and I've also noticed that my fuel economy is pretty bad. I put in a can of injector cleaner, but haven't noticed any difference yet.

I need some advice here real bad. My local mechanic has always been able to find any prblems with any of my cars I've taken to him, but do you think it's time to take it to the Buick dealer?

Thanks so much for the help! Bill

pcv

The smell coming out of the exhaust, does it smell like rotten eggs? If it is, the car has a misfire and/or running rough. It will be a good idea to take it to the dealer now and get it diagnosed right.

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tman

As for the check engine light, a messed up camshaft position sensor acts like that. I'm with pcv, get it to a dealer.

redlines4us

UPDATE:
After replacing the sensor on the air cleaner the #23 code disappeared into history. After 1 day of driving, the Check Engine light came back on. I then had a code #13 which was the Oxygen sensor code. I just replaced the Oxygen sensor and hopefully the light will stay off now and my problem will be fixed including the rich smell, bad gas mileage and rough idle. Seems like it's running great right now. I'm keeping my fingers crossed!!

Thanks guys!!!!

tman

no problem, I love it when we can actually help people here.