My jdm V2 STI motor finally arrived and I have been tinkering with it all week. One thing I am a little stumped by is the factory egt sensor located in the down pipe. My supplier cut the sensor wire about 6" up and it is a awfully strange cable with a spring in it. I ohm'd it out and it appears the sleeve acts as the ground and the spring inside sends the signal. The autometer egt sensors I have access to are not anything like it. I would like to run one but if it is not necessary (as I have heard) it would save some headaches. All I know for sure about it is that it goes into the ecu and outputs a warning light from the ecu. I would assume the oxygen sensors would handle fueling, so I am not really sure what this sensor is needed for. Thanks!

 

AFAIK it is just an additional safety measure for the cat more than anything else. Once EGT hits a certain temperature then the ECU warns that the cat will overheat. On a decat exhaust system it doesn't really matter so much. My EGT sensor looks like a simple cylindrical probe by the way.

 

Its a thermal switch only not a sensor, leave as is.

Bob

 

Would this be the same on my 1994 WRX? is it the sensor that screws into the bottom of the downpipe?

The reason i ask is that ive come to fit a decat downpipe today but can't get the sensor out of the standard downpipe, it's rusted solid and the nut is completely mullered.

So is it not needed? can i simply cut the wire or unplug the sensor further up?