Cross-Hair

Hey guys, I've got a problem. I just took my emissions test and failed. Recently (before the test) I had a crack in my exhaust manifold (/cat) and had it replaced with an aftermarket replacement part. I still however get a check engine light pop up once in a while (I made sure to reset the ECU before emissions, hoping it would still pass).

Anyways, I failed and have 10 days to get it back in so I don't get charged for another one (not to mention I'm supposed to get my car registered today)... so I'm in a bit of a time crunch and am hoping you guys can give me a hand.

My results are attached.

I'm hoping someone can figure something out and give me an idea where to look to get this fixed. I'm thinking it might be one or both of my O2 sensors. My car is at 165k miles and I believe they were both replaced at about 90k miles (not at all sure about this). The O2 sensors are supposed to read ~.45V if the mixture is a perfect A/F ratio and is supposed to read higher if it's richer and lower if it's leaner. The thing that confuses me is how low the readings are for sensor #1 (pre-cat) , yet so high for sensor #2 (post-cat).

Any ideas?

My other concern is that I might have reset my ecu too close to the inspection. I literally reset my ECU and then drove the **** out of my car for about 10-15 minutes to get the catalytic converter warmed up. Was this a bad idea? I've heard that it takes a few days for the ECU to re-adjust... the problem is that my check engine light also turns on after a few days. Any additional info?

Anyways, my car is a 1996 Civic LX auto 4 door. It has nothing aftermarket done to it except using a K&N filter. Also, the tranny has been swapped to an EX auto since it had problems a long time ago.

Any help would be appreciated, but try to be as detailed as possible.

Thanks.

Nosepicker

When you say K&N filter do you mean the air intake system? If so, that may be the cause. On my '97 Prelude, all I had done to the car was added a cold intake system and I failed the test. I swapped it back to the stock and I passed.

Cross-Hair

No, I don't have any intake system on the car, its all stock. The OEM air filter is replaced by a K&N air filter.

Anyone have any idea if reseting my ECU (pulling the battery terminal off for 10-15 min) right before the test could have been the cause for the failure?

Any tips anyone can suggest?

Cross-Hair

Anyone have any opinions? Should I include any additional information that I didn't mention in the original post?

Any input is welcome as it would help me narrow the problem down at least.

gearbox

iTrader: (95)

it takes upto a full tank of gas for the ecu readiness codes to go back to normal. if you reset the ecu and drive to smog, you will fail with almost every newer car. you want to drive thru at least one tank of gas. and what is the check engine light coming on for? could also be the aftermarket cat isnt as efficient as the oem. or that you didnt replace the secondary o2 sensor which is prolly bad if the old cat had failed.

Cross-Hair

Thanks for the response. I figured as much for the ecu... that makes sense. My CEL has stopped coming on for whatever reason, but I'm pretty sure the problem is still there.

The code was P0174 which was that the "system is too lean (bank 2)."

Anyways, I had a free one within 10 days of the first one so I took it in. The interesting thing is that my second o2 sensor read .995V for quite a few of the readings so I'm pretty sure it's the one that's messed up.

I don't think that the sensor got harmed by the old cat (it was replaced because there was a crack at the top of the exhaust manifold), but I do think that the wiring might have gotten damaged when we were taking the mani off and putting it on. I'll take a look and see if anything possibly shorted... otherwise it's time for a new o2 sensor (which I was already suspecting might be the problem).

Thanks for the info gearbox.

toy4two

I failed and am in the same boat.

I just had a Honda tune up (emission recall so it was free) and still failed. What did your HC and NOX numbers look like?

I bought a cat off ebay (hard to do in California) and bought a new primary o2 sensor. Also ran some fuel injector cleaner.

If it doesn't pass this time, I'm dumping 3 bottle of HEET into 1/4 tank of gas and will cheat to pass

Let us know your results.

gearbox

iTrader: (95)

try lubecontrol.com additives for oil and gas. reduces emissions