Emissions problem on my audi.

[monsterhunter]

Well guys, i have been constitly(SP?) failing emission while im trying to get this car to pass inspection. its the only thing im failing and i need some help here. i just bought a new cat, but i put it all the way back where the tailpipe should be. the HCs went down almost to passing but the COS went way up.my main question is; Since the cat is that far away from the motor is that whats causing the COS to go up? Or is there something else wrong? The car is a 1992 audi 100 quattro 2.8L with 187k on it. any question to help out just ask. and il try my best to answer it.



Thanks in advance Jay.

[BoostAddicted]

I have a question, is the area you put the cat in stock location ?? if not.. ill have explaining to do that might help

[Lucky7]

Off hand I am going to say it is not the stock location. That far back it is likely not getting the heat required to do the job?

[zippo855]

i am going to have to say that with the cat that far away from the motor 2 things are happening. 1, as mentioned, it is not heating up to the required temp to acutally burn off the excess fuel vapor. and 2, if you car has O2 sensors, as most cars did. The are usually before and after the cat in the stock location. By it not being in the stock location the O2 sensors arent getting a reading for whether or not it is running too rich, lean, etc.

[BoostAddicted]

Originally Posted by zippo855

i am going to have to say that with the cat that far away from the motor 2 things are happening. 1, as mentioned, it is not heating up to the required temp to acutally burn off the excess fuel vapor. and 2, if you car has O2 sensors, as most cars did. The are usually before and after the cat in the stock location. By it not being in the stock location the O2 sensors arent getting a reading for whether or not it is running too rich, lean, etc.

exactly what i was gonna say.. The O2 sensors are giving the ECU wrong A/F mixtures. its probly running to rich, when the O2 sensors dont sense that heat they tell the ECU to squirt more fuel in there to make up for that heat. and all its doing is confusing the whole cars ECU and function over all.. you need to put it back in the correct location. and then drive the car around so the ECU gets used to the old days.

good luck

[jimmythekid1]

Originally Posted by Lucky7

Off hand I am going to say it is not the stock location. That far back it is likely not getting the heat required to do the job?

I would have to agree, that is a good starting point. The O2 should not be an issue seeing that most pre 1992 cars only had o2 sensors before the cat.

[BoostAddicted]

Originally Posted by jimmythekid1

I would have to agree, that is a good starting point. The O2 should not be an issue seeing that most pre 1992 cars only had o2 sensors before the cat.

im pretty sure all cars O2 sensors are before the cats. cuz both my cars and my moms car have it before the cats. Its mainly just for recording heat. so yeah.. but im confused on why he moved it so far back..

[BART]

Originally Posted by BoostAddicted

im pretty sure all cars O2 sensors are before the cats. cuz both my cars and my moms car have it before the cats. Its mainly just for recording heat. so yeah.. but im confused on why he moved it so far back..

It has nothing to do with recording heat, it measures oxygen content in the exhaust and all cars that are OBD2 have them both before and after the cat. I will also agree with all those above that having the cat that far back will not let it work efficiently. Being a 92 it will most likely only have one o2 sensor.

[jimmythekid1]

Originally Posted by BART

It has nothing to do with recording heat, it measures oxygen content in the exhaust and all cars that are OBD2 have them both before and after the cat. I will also agree with all those above that having the cat that far back will not let it work efficiently. Being a 92 it will most likely only have one o2 sensor.

Very true, how ever a vehicle with more then one bank such as a v6 may use two oxygen sensors after each maniflold. But even most v6 have a Y pipe connecting both maniflod with one sensor after the Y. But some with dual exhaust would of had two PRE cat o2 sensors.

[BoostAddicted]

Originally Posted by BART

It has nothing to do with recording heat, it measures oxygen content in the exhaust and all cars that are OBD2 have them both before and after the cat. I will also agree with all those above that having the cat that far back will not let it work efficiently. Being a 92 it will most likely only have one o2 sensor.

Well from what ive learned in auto tech.. the main way the O2 sensors know your AF mixture in generally bassed off heat. the higher the heat the leaner the A/F mixture is.. the Lower the heat, the richer it gets.

[BART]

Chemical reaction, nothing to do with EGT.

http://auto.howstuffworks.com/question257.htm

[BoostAddicted]

Originally Posted by BART

Chemical reaction, nothing to do with EGT.

http://auto.howstuffworks.com/question257.htm

ehh, dont feel like reading all that. all im saying is thats what ive learned in school. My teacher was telling me about it. he said that chemical reaction does have a part in it. But Exhaust heat helps determine the A/F ratio.

[monsterhunter]

All right so, after my 12 hours of work on my friends 67 Stang(or as he bages FO D MUSTA G) we did a complete over haul on the 4 wheel drum brakes, after figuring out what parts were wrong and what not we got it all done faster...ANYWAY, after reading through and skippin the non needed arguing stuff. i have this stuff to say: 1. NEED to move the cat to near the stock ones(There is a universal one on it, due to only being able to get D.R's off line) and 2. I need to run alittle more Zmax and 3. run 93 octane(im runing 89 which is lower then it calls for[91 or higher]) And then we shall see what happens.
[QUOTE]well good luck moster hunter on getting that machine to pass/QUOTE]
and lastly, thank you, and Thanks everyone for all the help.

[texan_idiot25]

Zmax ain't worth anything.. Most fuel additives are BS. Only additives I've ever used were Restore oil for beat up motors (98 GMC Jimmy runs smoother on it, the Firebird got consistently better fuel mileage (plus the car sat for a while), the Laser stopped burning more oil than gas...). Does well for high mileage motors it seems. And sea foam is WTF awesome at cleaning carbon out of anything.

Run 93 octane from a good gas station for the test. You should run it that ways anyways, provides better power, and better fuel economy on that motor anyways. Plus, it's only 3 dollars more per tank give or take, worth it to run the car right. Emissions will often times run better too. Also, are you driving the car around a good bit before testing? At running temp it will run cleaner than when warming up.

And why would you put the cats way at the end?

[monsterhunter]

sea foam helps clean out carbon? im gonna have to get some of that. before i bought the car it sat for 3 years so i might need that stuff. also the my mom kept tellin me to put the 89 crap in, so im gonna switch over to that once im allowed gas money again. i get my gas form BP all the time works good in out the other cars. i put the cat alll the way back there becuae it was super easy and if i put it farther up it would have taken longer because its so low. Now im starting to think putting a custom twin turbo set up in the thing would be pretty kick *** too.

[Action B]

Originally Posted by monsterhunter

sea foam helps clean out carbon? im gonna have to get some of that. before i bought the car it sat for 3 years so i might need that stuff. also the my mom kept tellin me to put the 89 crap in, so im gonna switch over to that once im allowed gas money again. i get my gas form BP all the time works good in out the other cars. i put the cat alll the way back there becuae it was super easy and if i put it farther up it would have taken longer because its so low. Now im starting to think putting a custom twin turbo set up in the thing would be pretty kick *** too.

Yeah, Suck in that can of seafoam through a vacuum hose!

[texan_idiot25]

Originally Posted by monsterhunter

sea foam helps clean out carbon? im gonna have to get some of that. before i bought the car it sat for 3 years so i might need that stuff. also the my mom kept tellin me to put the 89 crap in, so im gonna switch over to that once im allowed gas money again. i get my gas form BP all the time works good in out the other cars. i put the cat alll the way back there becuae it was super easy and if i put it farther up it would have taken longer because its so low. Now im starting to think putting a custom twin turbo set up in the thing would be pretty kick *** too.

Then it sounds like the cat can't get hot enough to do it's job as well, thus poor emissions. If it's worth doing, it's worth doing right the 1st time.

To use sea foam, pour about a half can into a cup. Pull the vacuum booster line off and plug it with your finger, and have someone start the car and hold the RPMs up near 2-3k. Then, allow the vacuum hose to 'slurp' the fluid up... As in, hold it on the surface of the sea foam in the cup so it sucks fluid and air at the sametime. DO NOT LET THE CAR STALL, if it studders make sure your guy at the wheel revves it back up. If it stalls, you risk hydrolocking the motor. Get is sucked up as quick as you can and immediatly shut the car down. Let sit for 15-20 minutes. Restart it, and either rev the **** out of it, or drive the **** out of it until the steam stops billowing out of the tail pipe... The more carbon the longer it takes to finish the job. But, it can even clean the soot off your tail pipes, it's so awesome.

[jimmythekid1]

another tip before you test is to drive it on the express way for about 20mins. Also while waiting in line to test if there is a line hold the RPMs in neutral at about 2500. This will keep the cat nice and warm, allowing it to do its job the best.

Also make sure you can all optional loads of too such as air conditioning and the radio. Your battery should be in good shape too if its weak and alternator is full fielded you engine will need to work harder during the test.

Take some carb cleaner and spray all you vacuum line too. If engine rpm picks up you have a leak. Even a slight vacuum leak, due to being lean will raise combustion temps causing more NoX emissions.

good luck

[monsterhunter]

I'm gonna have to soon enough i really need to get this thing through inspection then, im gonna try to go for a twin turbo upgrade for it, to give it some real power and what not.

[monsterhunter]

thanks guys, all helpin pretty good, right now im working on relocating the car, im gonna get to it in a few days when im allowed to get gas again (almost on E) cant do anything with out gas then im gonan buy some sea foam, and ill try carb cleaner in the vacuum line as well. thansk for the help so far all great ideas and most likely help me out alot.