I bought a 91 civic w/ ZC motor, full exhaust, intake, he said it has a chiped and reprogramed ecu, It also has a v-afc. I failed emissions horribly, the CO was suposed to be at 12.0 mines at 22.2 and the others are high too. I think it is like that because it is running rich and i was wondering if i could fix that by trying to tune the v-afc. Or should i take my car to a shop and get the whole package looked at? I really hate going to shops with my cars tho. Any advice would be greatly apreciated.

 

do you hav a cat?

 

Is it a DOHC ZC? Here's some tricks to help you pass if it is:

-Swap out the ECU temporarily. If you usually use a PG7, swap it for a PM6 since it has leaner fuel maps. I'm pretty sure the CRX HF ECU can be used, which should run super lean.
-Check and adjust ignition timing to 16* BTDC (stock timing). Running the ignition at 18* BTDC is good for performance but will raise combustion chamber temperatures, which is bad for emissions.
-Use the lowest octane gas available. High octane gas burning cleaner is a myth. The octane rating is the ability of the fuel to resist knocking. Basically the higher the octane rating the slower the fuel burns, and the lower the faster it burns. If you run high octane fuel with the ignition on 16*BTC or lower you are not giving the engine enough time to burn the fuel completely. This means you are basically spitting unburned fuel out of your tail pipe, which is probably the worst thing you can do for emissions.
-Replace your O2 sensor (or at least check it)
-Check your plugs for buildup.
-Check your air filter.

 

or buy a sticker for 50$

 

Touche, salesman.

 

2 weeks ago it was $75, is there a sale on this week?

 

It is a DOHC ZC, and i have a high flow cat. Thanks for some of those suggestions, at least now i have somewhere to start at. I noticed that the guy doing the test does not bring the car above 4000 rpm, so do you think it would help if i tried to lean out the low throttle setting on the v-afc??

 

Definitely worth a shot.