Catalytic converter overheat warning light in dash

[IRISHDAN]

Hi guys, slight problem that hopefully someone can help with.

I stupidly got my leads wet and as a result developed a missfire. Didnt drive the car far and got my mechanic to sort them, basically drying them out. The problem is that as a result the catalytic overheat warning light came on and now wont go off.

My mechanic followed the reset procedure from his computer which was to disconnect the battery for over 30 seconds and (for some reason) depress the break with it disconnected for over 20 seconds.

He tried this a few times but no luck.
He has suggested just removing the bulb but I dont want to do that unless absolutely nescessary.

Any ideas?


DAN

[mx5ash]

I think it is just a heat sensitive type fuse thingy that blew when it got too hot, effectively earthing the light in the dash.
If thats the case you need to find the bit thats blown and replace it. Maybe in the sensor itself.
Pressing the brake pedal after the batt is disconnected will drain any residual current in the circuits and power down everything (ie the ecu) fully, thus resetting it/clear fault codes.
N.B If this has been done it may take a few drives for the ecu to relearn it settings and fuelling maps etc. Not sure if this is the case with the mx5 ecu but more modern ecu's kind of learn as the car is driven.
HTH
Ash

[IRISHDAN]

Thanks Ash, everything you said made sense. Do you know what is involved in replacing that sensor? I thougth I read somewhere that the sensor is accessable without taking apart the whole system.

Dan

[Steve]

Its just bolted into the side of your cat. Just unplug it and zip tie it up out of the way.
Is your car back to normal power?

[IRISHDAN]

Havent noticed any change in power. Should I get the sensor replaced or is removing it the best option?

[Steve]

meh.. well you know now that your cat might be toast. I'd just unplug it if you can. Is your car an early 90's mk1? If pre-93 (AFAIR) you can gut it without compromising your emmissions @ NCT time + pick up 5hp or so.