Didnt Pass Emissions

:banghead: Someone please help me out. Took my caprice for annual emissions and it Barely failed. To much unburned gas{hydrocarbons}is what the dude told me. Was thinking of replacing the O2 sensor and the air filter then retrying? Any suggestions? O yes, I did get the springs and shocks done all the way around and its sittin SWEET. I mean real SWEET. thanks chicago springs! please help me out why my car is not passing emissions.

:banghead: Someone please help me out. Took my caprice for annual emissions and it Barely failed. To much unburned gas{hydrocarbons}is what the dude told me. Was thinking of replacing the O2 sensor and the air filter then retrying? Any suggestions? O yes, I did get the springs and shocks done all the way around and its sittin SWEET. I mean real SWEET. thanks chicago springs! please help me out why my car is not passing emissions.

Any more specifics on your car, such as model year, engine etc?

My guess is that replacing the air filter is a good thing, but I'd verify there wasn't some other problem before replacing the EGO sensor. Was the car fully warmed up to operating temperature when you had it tested? Is it running on all 8 cylinders? Spark plugs or wires can contribute to this, as can a maladjusted carb (if your car is carb'ed). An engine that is not fully warmed up may not be properly burning all the fuel, leading to the HC failure. A vacuum leak can also cause HC failure by leaning out the mixture. In that case, failure occurs because there is insufficient fuel to provide a smooth burn, leading to an amount of unburned fuel going into the exhaust. A failed smog pump (AIR system) can cause HC failure by providing insufficient oxygen for the catalytic converter to do its job.

its a 91 with a 5.0 V8 moter. i believe all the wires and plugs are good. air filter is good. could it be the oxygen sensor? i no that controls the mixture of gas,.

if you could *ahem* create and exhuast leak at the exhuast side of the muffler, say by loosening a clamp, it should help some. That's how my neigbor got their van to pass... lol.

Did you get a readout of what failed exactly? Then we'd be better prepared to help with figures to go by.

Lean Out Ur Carb...itll Help Alot

Lean Out Ur Carb...itll Help Alot

No it won't. #1, the idle mix screws cease becoming a factor when the throttle plates open up, even slightly. #2, you run the risk of overheating if it is too lean at idle. #3, leaning out the idle too much WILL cause it to fail both HC and NOx at idle. Nonetheless, the car in question has TBI and not a carb, so there is no idle mix screw.

If you want to cheat it through emissions, you can retard the ignition timing a little (2-4 degrees) and adjust the idle speed higher (1200 in park).

Got the Diag. test ran and my mechanic dude said its a bad catayaltic convertor and i need a full tune up. was thinkin of doin plugs, wires, cap n rotor, O2 sensor, pcv valve, air filter, and of coarse the convertor. My mechanic dude said he will do it all for 350 does that sound fair? Should i put the money in it? can i still cheat it through even though the Cat. convertor is shot? Also the car seems to be eatin up alot of gas recently as well. Could this be because of the Cat. Convertor? If i invest and do the things listed above including the convertor do u think i will see a noticable difference in gas mileage? thanks

O2 can be watched on the scan tool or pull it out and see if it's coated white as this also creates a rich condition. Also check the injectors on top of the throttle body to see if they are spraying or dripping the fuel(dripping is not good).Tune up and O2 will help the emissions if they are needed,$350 is an excellent price if being done correctly and all that work is included.

i have a 96 caprice 9c1 had the same problem. got a good tune up done on it, plugs, plug wires, O2 sensors, throttle body cleaned, check all the idlers to keep it steady, last thing i did was to change the cat cost me alot of money on those cuz its a pain in the ass to find sum for a 4.3.

good luck!