trying to troubleshoot emissions on 3.2 Carrera
 

All,
I am in the process of trying to figure out why I did not pass TX state emissions. it's a 2 speed test...idle and 2500 rpm.

everything passed except CO was too high on 2500 rpm test.

Here is what I have done so far:

disconnected 02 sensor - no change
reconnected 02 sensor - no change
tried cleaning the connections - no change
bought a new 02 sensor - no change
connected brown CA emission wire to DME - no change
checked to make sure mixture set for high altitude under seat -
still no change

took off mass air flow and reset the spring in both directions- no change to allow it pass without increasing HCM's.

changed setting for mixture and makes HCM's go too high to pass

I can get it lean but HCM's increase when I do. HCM in texas needs to be below 200.

I even tested the brain with another one and no change..ran the same way .

bottom line is that for some reason, I think the car just is not recognizing the O2 sensor!
Anyone have any thoughts on what it could possibly be..spent 5 hours on this today and I am at a loss for words. Scratching my head. Would love to hear from the techies.

Thanks!
John

I had a euro premuffler on my 1987 Carrera 3.2 DME in Dallas, and it wouldn't pass. Had to put the CAT back on... sounds similar to your problem.. Bad Cat perhaps?

I have a fabspeed euro premuff and the mechanic said it should still pass but towards the end he was really beginning to suspect that might be the problem.

Well, that'ss your problem!! LOL

See if you can borrow a Cat from anyone nearby!

How's your ignition system? I think you've been bumping your head on the mixture scene enough, now might be a good time to look somewhere else.

Cheers,

Joe

I also replaced the rotor and cap and the car was running fine. any thoughts what else in the ignition it could be?

If Texas DMV is as strict with emission requirements as CA is, that thing will NEVER pass without a CAT! If you don't have a CAT, see if you can borrow one from a fellow Pelican in your area.... They aren't exactly cheap....

Does the engine seem to have a slight miss? Regardless, you might want to pull your plugs to see what they look like.

I had not pulled any of the plugs yet but they only have 15K on them. I am going to pull them just to make sure. People say that the car should pass without a cat but I am not so sure now....

My EXPERIENCE was that my car (1987 911 Carrera) would NOT pass without the CAT.... This was two years ago, in Dallas Texas on the Rolling emissions test..

Your problem has been diagnosed.... If there was a way to get a car to pass strict emissions without a CAT, don't you think they would design the system that way from the factory?

Duh!!!!!