Can anyone here with an EVO 8 tell me where the front o2 wires come from in the engine bay. I just bought an 05 EVO 8 and the front o2 wires are cut and no sight of them from under the car.

Also the wires (2wires) going to the oil drain plug are also cut/ripped. What does that sensor do?

There is also another sensor on the oil filter housing with no wires to be found. I assume that is the oil temp sensor? I have 3 Mitsubishi gauges (boost, temp, voltage). I was told these come from MRs? Anyways I assume that the oil temp gauge goes the the oil filter housing?

 

The front o2 sensor wires go up from o2 housing and to the left above/next to power steering pump. Then from there the wires go under-neeth the plastic ignition coil cover by the timing belt. Then from there the wires go out the back of the top of the valve cover into the wire harness right there.

 

I'm retarded. Yea after taking a closer look at the things the front o2 is good. The o2 sensor that is in that spot is just a plug for what once was a wideband. I've should of knew that that wasn't the correct o2, coming from owning DSMs for a awhile.

What about the oil drain plug sensor and that other sensor on the oil filter housing?

 

The sensor on the filter housing I have on my Evo too and I don't have the MR gauges so that is on all Evo's and its the oil pressure switch. The one on your oil drain plug I can only assume is the sensor and signal wire for the oil pressure gauge as I don't have a MR and I don't have those gauges because of it but I have read the one on the drain plug is for the factory three gauge set up.

 

The drain plug sensor is the oil temp sensor, the one on the oil filter housing is your oil pressure sensor. I couldn't tell you for sure what the color is but if I remember correctly its just one wire that may or may not be black. The sensor is very basic in that it just lights up if the oil pressure gets too low. I just replaced mine with an oil pressure gauge so I would know the exact pressure not just if it gets low.

 

How did you wire up the sensor and retain the factory output so the oil light didn't come on? Did the after market gauge have an output for the stock single sensor wire on it?

 

It doesn't come on unless the oil pressure is too low. The way the circuit works is that once the pressure gets too low the circuit closes sending the voltage to the light. So if you just pull it out there is no light, It's just like the power steering sensor. Will set off a code if it's present and monitors something out of spec, but if you completely remove it no light telling you its not there. And yes there is an output on the gauge but I don't think its the correct range for the light its more of there just for logging. I just watch the gauge but I really have no worries because I deleted my balance shafts so my oil pressure is a little on the high side.

 

If it's an 05 there is no factory oil pressure sensor on the filter housing. It is on the back of the block, if I'm not mistaking only evo 9's had the pressure sensor on the filter housing. As for the drain plug, that is your oil temp sensor for the factory MR gauge pack.

 

This is a very good point. If the sensor looks like the one in the picture its an oem oil pressure sensor, if not its an aftermarket oil pressure or oil temp sensor.

 

Yea it is definitely not that sensor in the picture. By the way mine is not a MR. I'll take some pictures tomorrow though.