ok so im trying to connect a cheap a/f meter. and i was curious of first wich o2 i should run it off of. the upstream one on the o2 housing or the downstream on the mid pipe? also where to intercept the o2 signal and if anyone knows wich wire is the signal wire.
Thanks for any help guys
~Ethan

 

You want to tap into the upstream sensor on the o2 housing. Remove the top engine cover and its the wires on the left if you are looking at the engine. Tap into the o2 wire not the engine wire. If you screw up you can at least replace the sensor. If you screw up the engine wire then it will be more difficult to repair. Someone correct me if Im wrong but I think the signal wire is the blue one.

 

You should run it to the trash can because this is the tuning forum and you cannot tune an Evo effectively with a narrowband sensor. Get rid of that garbage and buy are real "tuning" wideband.

 

True. The narrow band gauge is just a light show.

 

thats what i figured it was free and i was curious what it would read. would it at least be accurate on reading rich or lean?
thanks again for the advice

 

no it will always say rich at wot no matter what at wot...i really hope that was free

 

WOT its says rich, idle it sweeps back and fourth, on decel it reads lean. This is just a light show and is not to be used as a tuning device. It doesnt give you air fuel ratios

 

Why? It's junk and useless.

 

at least the blinky lights are pretty

 

lol ok understood. it was free and i prob wont waste my time even playing with it. i was just curious, so heres another quick question that i can get out of the way while we are still on the topic. with a wideband where would i place the o2 from that. weld anohter bung in or doest it somhow take the place of the existing upstream?
thanks guys
ethan

oh yeah narrow band A/F guage for sale if any one wants one. REAL CHEAP

 

If you have a test pipe you can put it in the bung after the test pipe. Of course you would have to leave the stock sensor plugged in electrically and just lay it under the carpet. Not sure if this would work though. I was going to try this when I get my wideband. Worst case scenerio you weld an extra bung in.

 

I would get a bung welded in .. it's important that you have the sensor high on the pipe in the 10 to 11 o'clock position if possible so that it's not in the bottom where water pools or it will crack the ceramic inside the 02 sensor when it heats up.