Macster

Well, yes there is. For a P0420/P0430 if the errors are accompanied by aging O2 sensor errors replace the sensors indicated, clear the codes, the resume driving the car.

If theP0420/P0430 error comes back, or are present without any aging O2 sensor codes, replace the converters indicated.

Now, with my Boxster I have managed to nurse a sick converter (the error code is P0430) for a number of years by running a top tier gasoline -- switched to discount station gasoline some years ago when gas prices skyrocketed -- Shell being the most common since there is a station near me that has competitive prices and is convenient to use.

questforbalance

Hey TsMcNeill. Durametric is a great diagnostic tool, as long as you know what all the data means. It is pricey thought, about $300.

questforbalance

Hey kcattorney, To see if you have bad cats your options are: to either go to Porsche and for an hour labor they will do a diagnostic test, or go to Harbor Freight and buy a Centech OBD2 reader for about $100 and check the codes yourself. I have the Centech OBD2 reader and the Durametric software which cost $300. Both work well. My issue is that I do not understand all the technical data. But in my case, I heard the rattle for a while, and was hoping for the best, I checked it with both readers and got the PO430 code, and erased the code for months only to have the code return every week. I then tried everything I could think of and researched like crazy. I even took the cat out and cleaned it, that work for an extra day, but that is it. So my options were to buy new OEM cats, which our local Porsche quoted me $6,000 plus $700 for labor, or buy OEM cats from Suncaoste Porsche in California or Sonnenporsche in Califormia for $1,700 each or have my existing ones remanufactured by Smithcat in Illinois for $450 each or go with aftermarket with Fabspeed. I chose Fabspeed and you can see my problem. Not sure what the right decision is or would have been, but as you can see I am still working on resolving a very frustrating problem. Good luck.

questforbalance

Larry,

Did you get po430 or 420 when you replaced your cats with the sport cats?
Thanks,
Fernando

morganabowen

Fernando, yes, a couple of weeks after installing the Speed Venture cats, both codes came back on and that is when he changed the 02 sensors. Since then, no error codes and it has been about 1500 miles

questforbalance

Thanks Larry, I am leaning toward new O2s. Update: Well, my wife just picked up the car from Porsche dealership. What a waste of time, but fortunately they did not charge me anything. All they did was hook up the pst2 to see that the cat is bad. They did not check anything else to see if anything caused it to go bad, if the o2 sensors were bad or anything. All they said was that these are aftermarket cats and they are far inferior to the OEM cats and that I should expect more CEL in the future. So I will hook up my Durametric to the car tomorrow and post on here and hopefully someone can see something in it that I can fix and resolve this problem. Thanks for great information and assistance. Fernando

alpine003

You guys over analyze and make things way too hard...

dgmark

The only way to diagnose the problem is to look at the wave form for the rear O2 sensors and compare them to the front o2 sensors. You can do this with the Duramemetic scanner, you cannot do it with a cheap code reader. A proper wave form for the rear O2 sensors will have very shallow peaks and valleys because their should be very little oxygen coming out of the cats ,Think of small waves. The front os sensors will have high peaks and valleys as the PCM controls the fuel trims. If the rear patterns are following the fronts in unison, the cats are not doing there job. Short of an exhaust leak and assuming the O2 sensors are functioning correctly, I would condemn the cats.

It takes some experience to diagnose a failing O2 sensor, when they get weak they will not generate enough voltage or flat line and the voltage will not change at all. When this happens it will normally set a code for the O2 sensor but not always. The cats and O2 sensors have to be hot. The O2 sensors have heaters built into them to get them up to temp faster. Sometimes the heaters will fail but again this will most likely set a code for the heater circuit.

I see aftermarket cats throwing cat efficiency codes all the time. There is a reason why the OEM cats are so expensive. Yes you can fool the PCM using O2 extenders, but after spending big money for the aftermarket cats I would hold the manufacturer feet the the fire to correct the problem or refund your money.

Here is a generic image of the O2 wave forms, The top is what the rear should look like, the bottom is the front. If the rear o2 sensor looks like the front, the cats are bad.

Your time at the dealer was not wasted, It does not take a lot of time to look at the data, and they see aftermarket cats causing this type of problum all the time.

questforbalance

Hey DGmark, Can aftermarket cats be fixed or made to work? I am in discussions with Fabspeed and they will test, fix or replace the cats? Even though the salesman insisted that all I needed to do was add extensions, their Porsche tech agreed to help me out and fix the problem. We got to this point after they spoke to the Porsche dealership. However, I did not feel comfortable hearing the Porsche dealership mechanic tell me that these aftermarket cats are weak and will throw inefficiency codes again in a short time.

dgmark

Your tip off that they will not correct your problum is the fact that they want you to use the extenders. What that does is pull the O2 sensor out of the direct exaust stream and slows down the O2 crossover on the rear O2 sensor. A proper "Quality" cat will not need the extenders and If you are in California the extenders will most likly fail the visual inspection. The funny thing is that it is random with aftermarket cats, some have no problums

questforbalance

Thanks DG for the response. Well, I am glad I have the Durametric, it is fun to use, but I can't tell if anything is wrong with anything. Here are a bunch of values, so if someone can make sense of this, please let me know.
Pre and post cat o2 sensors results were nearly identical.

Bank 1
Rear O2 voltage .09 to .8
resistance reading 64
Front O2 voltage .10 - .75
resistance reading 64
Oxygen sensing fluctuated very slowly between .99 to 1.02, but mostly stayed steady at 1.00.

Bank 2
Rear O2 voltage .10 to .8
resistance reading 64
Front O2 voltage .09 - .77
resistance reading 64
Oxygen sensing fluctuated between .99 to 1.02


Engine temperature 90.8 Celsius (195.44 degrees F)
Exhaust after cats 320 degrees Celsius (608 degrees F)
Carbon Canister load fluctuated from .06 to .27
Cat mean amplitude 180 for each bank
Hot Film MAF 1.25
oil temperature 86.3 Celsius (187.34 degrees F)

Ready Status:
Everything except for catalytic converter efficiency passed.

Can anyone see anything in these values that would explain the PO430? The CEL was cleared at dealership.

morganabowen

Fernando,
This is the unit that I installed in my car. Not only did it clear the codes, but in really increased the performance and sound of my car
It is important to remember that it will pass emissions, but it will not pass visual inspection in California. It just depends on where you take your car for smog testing. Good luck.

dgmark

Ok, It looks to me like the cats are not reaching threshold temps. The cats lite off at 650-700 degrees and normally run between 800-1100. look at 2 more things, check the long and short term fuel trims, they should be between -5 and +5, they will fluctuate higher and lower thats OK we are looking for an average. Next run the engine at 2500 rpm and let me know what the converter temps are, we need them to be above 700. If you have an infrared temperature gun that goes over 800 degrees you can check the inlet and outlet temps at the converters. You are looking for a 100-200 degree increase at the outlet temp, that means the converter has lit up and is working. If on extended idle the converter temp is dropping below threshold temp that is what is setting the code. I want to tread slowly before condemning the cats because your original problem was only a p0430 and this code has continued even after changing the 02 and cat lets see if we can nail down a definite diagnosis before jumping on anything. "but I still think its the cat."


Class, Class, "Wake up"

TSMacNeil

dgmark's knowledge far exceeds mine on this, but I do know that there should be a marked jump in measured temps between inlet/outlet of the cats at operating temperatures. Also, in a 4-o2 system, the pre-cat o2's should be busily dithering between .01 and .09 vdc.....and post cat o2's should be fairly voltage stable at .5 or so vdc if they are monitoring a fairly stoich exhaust.

I know how to measure those things manually, but am unfamiliar with code readers....so I would heed dgmarks' advice...it looks sound.

alpine003

I agree but reality is 200 cell cats have been known to cause cel lights in all cars, and not just specific to Porsche. Having more flow and less filtering, you are always rolling the dice.

As you said, the problem isn't consistent and can be random between cars. One explanation is that manufacturers often update their ecu's slightly throughout their production run to improve or account for any previous issues or make minor improvements. So some might have slightly different parameters, including a lowered cat threshold value.

With OEM readers you can see the ECU revision version(can't remember off the top if Durametric displays this). That's the reason why some guys can run a full cat bypass with O2 extenders and not set off a cel, while others with a more finicky ecu version will trigger cel even with performance cats.

If we actually had a decent sample set with peeps running performance cats and with ecu revision #s recorded, you might see a correlation with certain versions.

But as indicated OP indicated, you can check the temps to make sure you didn't get faulty cats.

Oh btw, if you ran too much JG-DT40 oil, you have only yourself to blame for cat malfunction/ failure.