so i got me new exhaust with a high flow cat installed cus i needed to pass emissions. i went in today and i failed. really bad. i cannot put the stock exhaust back on, i think i didnt pass because i have such large fuel injectors (550cc) on a small engine. does anyone have any tricks or advice to pass next time? i cannot put the old injectors back in because i dont want to mess up the tune i have on the car now. will running a higher or lower octane fuel help out at all?

 

Why did you fail? Too much C02 or NO?

Is everything else OK on your car? O2 sensors?

What state are you in?

Can you get friendly with a private emissions inspection? Any reason you can't put the old exhaust on. or at least the catalytic converter>

 

ok here r the numbers. HC 9.4951: legal limit is 1.2, and CO 64.5208: legal limit is 20.0. im fine on the CO2 and NOx. they said the reason i failed the HC is becasue i have unburned or partially burned fuel too much i guss. and i failed CO because the air/fuel is too rich, thats bs cus i had great a/f on the dyno lastnight. i live in colorado. i cannot put the stock cat on because there is no way of attaching it to my car i have a magniflow high flow cat on there now. all the o2 sensors r fine. and i dont know anyone who runs these test. also the stock exhaust is out of the question because i cannot attach it back up to the turbo i have the wrong flange and its too small.

 

You're running too rich. Unburned hydrocarbons in your exhaust means that gas didn't get burned in the combustion chamber, which means you had too much in there. Try turning up the boost. If all else remains equal then that should even out your A/F, I think.

 

no im not too rich. i had perfect a/f ratios on the dyno the day before, no problem what so ever. dirka dirka

 

If you have cat on you need some tuner to tune your car so you can pass. That is how we do it or we pay some money under the desk to the inspector

 

i really dont wanna mess with the tune cus teh car is running so well. im gunna have to find a way to pay some one off. will changing my octane help

 

2ND that, whil you may have a perfect tune at wot, it isn't easy to tune a healthy 14.7 at idle with big injectors. I;d recommend, throwing in stok ecu, injectors and maf housing and running low boost. also you will need put 200mi on the set-up to get the readiness tests to pass

 

You might want to use an oxygenated fuel like gasahol. Maybe an additive from an audo parts store.

The only problem with this is the O2 sensor will tell the ECU to run richer.

Can you fool the O2 sensor to run lean?

 

Yeah...3rd that, your A/f may be good at wot...but i've never heard of emmssions test that measures tail pipe emmissions at wot. I know that auto zone sells some stuff that gaurentees you to pass an emmissions test and if you do fail they give you 3 times your money back. The stuff is like 7$ so either way i guess you win somewhat...i've always wondered if it works at all. I'd be careful with that stuff though...who knows what else it's going to f up