I have an 02 Porsche 996 Turbo.

Failed Emissions Test Miserably.

Hydro Carbons: Vehicle Reading 1.1138; Maximum Allowable is .3700 Average Passing is 0.0664

CO2 Vehicle Reading 12.0438; Maximum Allowable 6.2100; Average 2.1635;

NOx Vehicle Reading 1.6396; Maximum Allowable is 0.9300; Average is 0.2752

I went again and had the car near empty and there in a gallon of Methyl Hydrate... Results were better but still failed.

I took the car to several shops... No codes are popping up except for Crank Position Sensor. However, I doubt that has anything to do with Air Emissions. I changed oil.

I was then advised it could be anywhere from the O2 sensor, to Mass Airflow Sensor, to MAP sensor. I also had one guy saying that it could be the CATS just by looking at the results. Any advice would be appreciated. As I don't want to go on a goose chase looking for an issue that may possibly be meniscule.

Any advice will help.

 

Is the car modified, mostly stock or stock? Those numbers do seem way off. At my last smog check in October, I literally had zeros across the board (I though maybe the testing machine was broken ). These cars are suppose to run pretty clean. What kind of numbers were you seeing before?

 

I think the Exhaust is by RUF. Other than that its pretty much stock. It's also consuming an insane amount of gas. Any one know which part I should start off with????

 

What do you mean you think? All you need to do is look under the exhaust and you will see a small tag that says RUF with a part number next to it. Mine passes the sniff test with no problem. Something is off in your case. Make sure you get the exhaust really hot before getting tested.

 

It's a RUF Exhaust...

I drove the car for one hour at 100 kmph straight and revved it extremely high. It still failed. Although not as bad as the first two times.

I know there is something going on as the car is consuming a lot more gas then it use.

I should also mention, I parked it for a few months during the winter. However have driven over 1500 km since parked.

I also used 2 gallons of methyl hydrate with a quarter tank of gas, and I still failed.

Anyone suggest what else it could be?

I recognize its off.

Also, it should be mentioned that I passed the OBD portion of the exam but failed the driving test....

Thanks....

Karim

 

I think the first thing I will attack is MAF sensor then probably the MAP sensor. Ill take it in for emissions again. If I fail then I will look to replacing the O2 sensors. If these don't work I guess i will change the CATS. Does this sound like a good attack?

 

I think your problem is this:

"except for Crank Position Sensor"

 

My car is modified and has RUF exhaust with 100 cell cats. Cold will not pass, warm car passes smog with flying colors

 

Hi karimhamir,
It appears to me that you have multiple problems. With these IM240 numbers, for sure you cats are defective! No amount of methyl-hydrate is going to help!! You need to replace your cats. And don't go cheap, to meet the maximums for your vehicle, high quality catalytic converters are a must. Your crank sensor code needs to be addressed. This is one of the most critical components for engine management and vehicle performance, why would you not get that fixed right away? I'm surprised you don't have misfire codes to go along with the crank sensor DTC. How did you pass OBD with a crank sensor code. Lots of great emission techs in Van, have you had anyone check it out?

 

Do you know any emission techs. Anyone know how to get to the crank position sensor if I did it myself???. If cats are the issue then I am going to have issues given that the exhaust is a ruf. It's come to my understanding that the Porsche cats are attached to the muffler and exhaust and I have to change the entire unit.

I am going to try to change the cps then take to air care and see what happens.

 

If it wa the cats. Wouldn't the cat dysfunction show up during the scan

 

I'm surprised with the engine so 'dirty' that the CEL is not on and one or more error codes *(besides the crankshaft position sensor) are not present.

Also, I am surprised that the car would not fail emission test simply due to the readiness codes being set to incomplete. Hard to imagine with the engine running like it is, as dirty as it is, that the readiness codes are set to complete.

Does the car have a custom 'tune' or flash to go with the aftermarket exhaust?

I do not know anything about using methyl hydrate. I'd run this out and not use it again. Just fill up with top tier gas from a busy station.

I assume the engine's in good tune? Plugs fresh? The right plugs? Air intake filter ok?

Also, like speedfreak said I would get that crankshaft position sensor addressed.

If the engine smells like it is running rich it would be interesting to know what the long term fuel trims are. Course these are reset when the error codes are erased and it takes driving for the DME to relearn and adust the long term fuel trims. But I'm not sure I'd continue to drive the car: More on this below.

Anyhow, if the long term fuel trims are on the rich (plus/positive) side the DME is adding fuel. This may be due to a bad coolant or air intake temp sensor which is fooling the DME into thinking the engine or air temp is colder than it really is or the fuel system pressure is less than it should be. How's the fuel filter?

If the long term fuel trims are on the lean side (negative) it is the DME removing fuel. The fuel system could be over-pressurized or fuel injectors are leaking.

If the engine is really running rich gas could be washing oil from the cylinders so you do not want to drive the car until you get this sorted out.

And of course change the oil after.

Sincerely,

Macster.

 

The last couple postings are pretty scary. I never realized that the engine could be considered 'dirty'. I guess I will have to bite the bullet and get new CATS.

Has anyone replaced the CPS on these cars and are they hard to do.

I am going to take a stab at it on Friday.

Any other suggestions would appreciated
....

 

Here's a dumb question, are you sure someone didn't drill the cats out of your ruf exhaust? Not sure why anyone would but I've seen guys drill out the cats on ep's so anything is possible.
Try to locate a stock exhaust and get it tested again.

 

I was thinking the same thing...

OP has no idea WHAT he has...bought a used car. He may have NOT CATS and someone reflashed the DME to ignore the cat codes....

He needs a real shop.