O2 and EGT: Help
 

Can someone please explain the differences between EGT and O2. I know the obvious, exhaust gas temperature and oxygen but are these two separate sensors? Where are they located and what/where are the wiring connections? I have reviewed the wiring diagrams and I can only find an O2 mentioned, help for location is useless. I am reinstalling an engine that I did not remove so I have no point of reference for this. Any help and pic’s would be appreciated.

I'm sorry, but if you have to ask that, you should NOT be installing an engine!

The o2 sensor is located in the downpipe/pre-cat...pretty much like in any other car. There is no factory EGT gauge (which measures temp, not o2 concentration, I don't know how you could confuse the two).

Well, you may be right about the engine. Most of the install has been straight forward and the forum has been a great resource of information. This O2/EGT issue is something I thought I would try and get some addition clarification on due to the lack on documentation and the leftovers from the previous owner. Some of the confusion comes from the stock Exhaust Overheat warning light in the center console and the heat hazard sensor, location?? The wiring diagram documentation is useless in identifying the location. The O2 sensor the previous owner was using with the Wolf 3D EMC does not fit the stock size O2 bung in the downpipe and apparently hacked the stock connector out of the grossly hacked up wiring harness. With all of the discussions of EGT I've seen nothing on installing the sensor, what make of sensor and who carries them.

The factory Exhaust Overheat sensor is for the stock main cat, it's not there to measure EGTs. Sounds like you've got your hands full with another hacked-up FD...:(

The overheat sensor is in the passenger floorboard - it's NOT a critical sensor by any stretch of the imagination. Mazda had to put that in the car to pass federal emissions laws at the time - the system is really pretty much useless.

Many people install aftermarket EGT gauges to measure exhaust temps as a tool for tuning an engine in. This is a probe installed in the downpipe. Unless the car came with an EGT gauge, you don't have to worry about it.

Dale