Ok about 3 weeks ago I installed Brian Crower 272's in my 03 evo 8. The install went great. The car started up just fine the idle was lopey but it never dipped too low where the car would die or stall. I haven't yet got tuned at this point because I just recieved a zeitronix wideband and wanted to wait to install it so I could get it properly tuned. The car has been running fine either way. Last week, one morning I was pulling out of my driveway when I ran over an ice pile I didn't see I could hear it scrape the underside of my car and immediately my CEL came on. I pulled the codes and they were 0130 0135, 0138, 0139, and I think 0137 all rear o2 sensor codes. I figured I pulled some wires out or damaged the sensor, but the car still ran fine. I looked under the car and the wires looked ok but I never jacked the car up to inspect and figured I'd check it out later. Sunday afternoon I thought I would install the zeitronix. I dismantled the center console, jacked up the car, and decided I just didn't feel like doing the install anymore so I put it all together and went inside for the rest of the day. This mroning I start the car for work and after it warms up I hear the RPM's dipping and it idling very rough. All the way to work it idles horribly and dies a few times and then when I'm almost at work it starts to idle normally. I decide that after work I'd take a closer look, so at the end of my shift I inspect all the fuses and they seem ok. I drive the car it idles really bad, dies sometimes, and then occasionally idles fine. Now I'm stumped!

Some quick questions I have

Would a damaged rear o2 sensor make the car idle really rough and die?

What is the fuse for the o2 sensor, is it the 20a engine fuse under the hood?

Could I have pulled something out under the center console, like maybe a ground for the e-brake, that would make the car idle like ****?

The car drives just fine and pulls hard no sputtering, or problems under normal driving conditions. Idle is just horrible

Help me please!!!!

 

I don't know that I would be doing a lot of pulls without some tuning on those cams, even a base map. You should really get that wideband hooked up just to make sure it's safe as is

 

I was really just testing to see if the car had any other problems throughout the rpm range. And I did some 3rd gear pulls to log the car to see if anything is up. I was going to get tuned for now anyway because I just don't see the zeitronix getting installed for at least a few weeks now but would like to get my idle problems solved.

 

You'll need to turn up the idle with ECUFlash Ill copy and post my idle setting with the same cams

 

I don't think the rear o2 sensor would could the idle issues, but the front one might. With that said, I hightly doubt the front one could have been damaged. It's not as exposed as the rear.

Try resetting ECU?

 

I was just going to reset the ECU and noticed the front 02 sensor harness was unplugged!!!??? of all the stupidity, I must not have clicked it in well when the cams were installed and it popped itself back out ughhhhh I hope it didn't burn out the sensor, the car is warming up now. Here I was thinking that maybe I didn't torque the cam angle sensor bolt enough and it started to back out... I was scared.

Thanks for the replies guys

 

NP. Glad the problem was something simple and fixable.