SCL

I've tried to figure it out. My mechanic says it needs new CATs. I don't believe it. The CATs are only 4 years/40,000 old.

I've checked:
1 fuel pressure - right on the money
2 fuel injector output 30 second test- perfect
3 installed new champion plat plugs - I know but they are new, and I watched the spark by turning the engine with the fuel fuse out. It looks good to me.
4 changed the air filter
5. used my VAG COM tool on my laptop and everything is where it should be.

It passes barely at 2500 RPM. But the HC count is 4 times the normal limit at idle. I think it's running rich at idle. He says the CATs burn off the extra HC when they are working. I don't believe it.

what do you guys think?

4Driver4

Chipped? Boost leaks? Any codes? "installed new champion plat plugs" SRLY?

SCL

I put the original chips back in. same exact readings. no boost leaks...and at Idle I can't see a boost leak doing it. no codes.

I meant to write that the CO is high and the HC is way high, 4 times normal.

I suspect mass air flow or idle control valve. I checked the ICV and it seems to be free and working.

I just don't believe it's the CATs. Do you think that's possible. It just sounds like a half *** diagnosis.

Stuklr

What is your mileage? Possible O2 issue. The sensor should catch a rich condition (high HC's). Don't count on codes with an OBD system this primative. BTW don't use anything but the factory plugs. Could just be poor combustion.

UrS4boy

no problems even though my engine is RS2 equipped.

HC Max Allowable = 0.5000 g/km, my car = 0.0950 g/km

NOx 1.24 max allow., mine 0.0439 g/km

CO Max = 9.32 g/km, mine = 6.3386 g/km (okay)

(This is on a four wheel dyno)

Original 93 cats.

It still could be your cats.

Xel

get a new oxygen sensor!!!

alpinab7

Plugs won't do it. Any false air (leak), even small, will.

450exc115

Cats have little to do with HydroCarbons. Cats take NOx and CO and turn them into NO2 and CO2 which are more friend gasses for the enviroment.

Hi HCL sounds like it's running rich. O2 sensors, dirty injectors, bad fuel pressure reg. Lots of possiblity but for some reason Audi seem to chew through O2 sensors so I would start there..

chefbob

which one?

chiitown

I too refused to believe it was my CATs'. After failing 3 times and doing and replacing everything you could imagime. O2 sensors, changing oil, plugs, wires, cleaning egr port, Seafowm total treatment, etc... I broke down and replaced one CAT. The result was my HC reading went from 1.09 Grams/Mile to .65 Pass for my area is 1.00 additionally my CO went from 9.56 to 2.84 Pass for my area is 12.00 My nox also decresed from 3.83 to 1.03 with pass @ 2.50. So if I was you, I wouldn't rule it out. Even as hard as it may be to believe. I banged on them etc.. No marbles or nothing.
Good Luck, I know from the 4 time for one car, emissions is a royal PITA sometimes.