I have a 01 996tt with speedtech exhaust, flash,intake....I had the test done 2 times and the HC reading keeps coming in at 164. The levels are suppose to be between 17 and 100. Everything else is within range.

I am in CA so I have to get this fixed. Any ideas???

CAA

 

what kind of cat are you running? if stock, you could possibly have a failed cat. I think in CA exhaust system is covered for 8 or 10 yrs. high HC means you are burning rich or incomplete combustion. this is likely old cat or bad ecu tuning.

 

Its a 2 year old cat that came with the Speedtech Exhaust i purchased in 2008.

 

If you still have stock, swap stock in. It should be ok.

 

Could you post all gas number: Nox, CO, HC, O at both rpm ranges. I might be able to help. I guess it is 4wd so test was done off dyno, right?

 

Stock is long gone...Maybe John can send me replacement cats since i think they should last longer than 2 years...

John , are you out there listening????


The numbers are HC CO

RPM %CO2 %02 Max AVE MEAS MAX AVE MEAS Results

738 13.4 1.0 100 17 164 1.00 0.00 0.55 fail

2362 13.6 0.7 130 12 17 1.00 0.10 0.63 pass

 

CAA,

Yes, I just sent you a PM with a few options, but we have never had this happen before, so I am not certain what the cause is...Yes it could be cats, but it could be a host of other things as well. For instance, if your car is running rich due to a stuck FPR or improper tune, you will burn the cats out in no time and run very rich all the time regardless of cats. Tough call without knowing what is causing the problem.

 

Was both smog test done at same place? It failed at idle on HC @164 with max allowance @100. Was your car warm up pretty good?

 

100 cell cats sometimes do not hold up and usually in Cali they will not pass ( No matter who's exhaust it is)... either get higher cell count cats or swap for stock exhaust... do not expect 100s to pass...
just my opinion
markski

 

This is our original twin cannister, 70mm, 200 cell cat exhaust that has passed before on many other cars.

 

What are the NOx numbers as they usually give a good indicator of the cat's condition.

Strange that the HC number are so clean at the higher RPM. That would tend to indicate a miss or unburned fuel at the lower engine speed. And the 02 number, 1.0% at idle could indicate a vacuum leak.

Tinker

 

Both tests were done at the same station. Where do i find the NOx numbers. It isnt on the smog check sheet...And the car was warm..

 

- Would be hard to use Nox. This was TSI (two speed idle) not done on dyno with load. Nox won't show that much.
- It got lot cleaner at high rpm.(but it is not miss at idle. When it miss, it should show higher number.)

 

Any porsche smog guys in orange county?

 

You are sure that your engine was hot. We could make further assumption. (Cat is not funtion well when not hot. And engine might also in rich idle when cold.)
From your number, you could see high HC and moderate CO and some amount of O2 left. Cat suppose to process HC, CO mix with O2 to make no harmful gas as H2O and CO2. But from number it tells that sys is somehow rich (not much). I say it because of present of moderate CO. Ask Smog tech to measure before Cat and after again to compare.
1. If number are not big diff between before and after, your cat is shot and need replacement.
2. But if number before cat is lot higher, it means your cat is doing the job but could not handle the high amount of HC and CO. You have to check what cause sys to be rich: struck FPR, clogged airfilter, not proper flash.