I failed my emissions test it's running too rich at idle, but the 2500 rpm test passed with flying colors. Any ideas? I am not throwing any codes I checked that already. So I am not sure what it is. Car is in my sig.

 

I had the same exact problem for the last few months but my car finally passed. After about 4 months of trying to fix my car myself, i finally brought it to a shop and they got it to pass. They say that my O2 sensor was lagging and slow to cross count after letting the car come down from high RPMs to quickly. When they ran the test, they would rev the car and slowly release the pedal so that the o2 sensor could keep up. It was a brand new bosch sensor but one of the guys said that he went to a class about o2 sensors and found of that the older ones actully cross count better.
If you dont want to bring it somewhere, i would start by throwing some injector cleaner in there, cleaning up the TBI, and maybe lowering your fuel pressure also you want to make sure that all your sensor are working properly. I would bring it somewhere and pay someone to fix it for you, it was the best 125 that i ever spent.
Also, what were your smog readings
at idle , mine went from 311 HC to 11 HC and 1.63% CO to .01%, so the professionals know what they are doing.

 

pretty sure mine was 293 and 1.6x or 1.5x % but it was around there somewhere, I am betting it's the same thing. Thanks I'll look at that. Maybe I can pick up a that part from the dealership. I wouldn't mind getting the original equipment if it works better than the bosch.

 

also, what are your mods?

 

just a K&N, not sure what the guy who owned it before me did, he said just a rebuild and bored it over .030

 

My 91 bird w/305 always failed emissions tests the first couple times too, running to rich at idle, so i figured out that if i did a complete tune up a couple days before the test it would pass. Also after I added my thermomaster chip it seemed to be running leaner at idle and had no probs passing. this was before my other mods, and since i did my them, I moved outa illinois so i dont have to take emission tests no more.

--Stormr

 

Cool that's what I was thinking about doing, so i'll probably just do that sometime next week. I get one free reshot, maybe I'll pass this time.

Any other ideas?

 

I dont know if they have this there, but at the local auto parts stores in illinois they have a bottle of stuff you pour in your tank called "emissions pass" says it guarentees a pass every time. i never tryed it though, but do some lookin around, you could probably find something to help out.
--Stormr

 

Great idea, if all else fails, I would rather fix the prob though, cause the frekin smell bothers me.

 

if your running rich at idle, the Guarantee to Pass Emission stuff wont get you to pass, but it will help. Do a complete tune up and see where that gets you, but usually if u are that much over the limit, it will have something to do with you sensors. good luck.

 

Which sensors? I just got news that my dad is going to take this car when I am done with the body work in like a month and get my settlement from my wreck with the ta, so I'll be back in an LS1! But as for this car I don't want to give it to him running rich on idle, do you know which sensors to check? Should I check the haynes manual?

 

I wound up replacing almost all my sensors, and it always kept running rich, the ones i replaced and as far as i know have anything to do with the prob is the IAC , TPS also if the coolant temp sensor (the one for the engine, not the guage) goes bad wich mine has before it will run very rich, but it will flood the engine, so its probably not that one, some sensors are cheap, the tps was about 30, but the iac sensor was 70. But it sould have something to do with one of them. good luck with it.
--Stormr