reprogramming ecm effect on smog test
 

Hi guys. This is my first post on here as you guys pretty much covered every thing else, there's simply no place else that has straight forward real world info. In a nutshell, '97 z34, 137,000, runs/shifts fine but is lacking power although not too bad yet. Beenresolving one code only to get another immediatly, now itsa P0420 (cat) code. Decided on the hi-flow cat from ZZP, u bend remover, and o2 emulator. My car is not listed for the emulator, so I wrote them asking if there is one that will work.My problem is the registration expires in 3 days and I havent enough time to order, ship, and install. Ierased the code to turn out the light hoping to pass smog for now, but the test is rejected because all sensors havent been through a run cycle, yet the SES light comes back on within 15 minutes of the first drive. If I were to reprogram the ecm to not registerpost cato2 sensor, would thatnot be picked upon the smog test as well? I've been at this for a few months now and i've come to truly despise that SES light. Any ideas how to pass smog until I can change the cat? I'd really apprecite the help......

RE: reprogramming ecm effect on smog test
 

Umm... I think you are SOL. Clearing the code is fine. Deleting it with a programmer to pass a test is illegal.

One possible option you have is to find someone with a similar car and temporarily put that downpipe on, pass the test, then give the pipe back.

RE: reprogramming ecm effect on smog test
 

I post to quick.

One problem you will run into is when you have to test for emissions again. The ZZP pipe will throw a code and you will just fail it again. You will need to get your hands on a stock cat just to put on temporarily.

Another possibility is to try to clean the cat. I am not by any means a genius on this, but there may be a way to take the downpipe off and "wash" it out. I'm sure there is some chemical that can clean it but I have no idea what it would be.

I wouldn't worry about ruining at this point either if you are going to get another one.