Just curious if anyone out there has ever replaced their MAT sensor? This is the sensor that screws into the side of the air cleaner housing. This sensor is not often talked about here on the Forum as far as I know. Did you did replace yours and if it fixed your drivability issue, what was that issue? Lastly, how do you test a MAT?
Thanks, Kit
P.S. 4 cyl Fiero's don't have the MAT sensor.

[This message has been edited by Kitskaboodle (edited 05-18-2014).]

You can scan the ECM and see what the MAT reading is compared to actual temperature.

You also can read the resistance of the sensor and compare it to this chart.


Yes CTS and MAT use the same response curve.

Thanks for the chart.
I was just reading one of my "other " Fiero service manuals (a Haynes manual I paid two bucks for) and it said you can check the voltage signal going from the MAT to the ECM and it should be 4 volts. Does that sound correct? Just trying to gather all the tests that can be done to verify the MAT sensor is working correctly.
Thanks, Kit

quote Originally posted by Kitskaboodle: P.S. 4 cyl Fiero's don't have the MAT sensor.

Wrong. 87 & up L4 Does.

V6 MAT connections and wires can corroded etc make an iffy reading cause problems w/o setting Any DTCs.
You can try testing w/ above chart but don't hold your breath.

See my Cave, Sensors Quick Ref


------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

[This message has been edited by theogre (edited 05-18-2014).]

You can also check the MAT sensor resistance with an Ohm meter. Unplug the wires, and probe the two terminals. Then compare to the chart above. It should correspond roughly to the ambient air temperature.

I had to replace the MAT sensor on my V6 once, because the reading was WAY high. We're talking sensor readings around 140°F, when it's only in the low 70s outside (cold engine). That made the engine run lean, which made it surge and sometimes stall when idling. The bad behavior happened mostly when the engine was cold, because the O2 sensor wasn't active yet.

[This message has been edited by Blacktree (edited 05-18-2014).]