Heavy oil consumption? Since when the car was new, the engine was burning 1 quart of oil every 1100 miles, and did not improve with break-in. I have always wondering such heavy oil consumption could cause sludge or soot to build up somewhere,

or...

HPFP? My HPFP has been replaced 3 times. Suboptimal fuel combustion would lead to premature catalytic converter failure?

I ask because my dealer did not offer any explanation. Sounds like they are just replacing whatever breaks, but not looking at the problem systemically. Since they are still waiting for parts, I thought I should learn some knowledge first. Mine is 2009 Carrera S Cab, thanks.

 

Your cat was most likely ruined by either overheating due to gas in the exhaust or contaminated by motor oil.

Early failures in cats are often associated with a bad exhaust valve. One piece of information that would be interesting is a compression test. The other thing would be to pull the spark plugs and have a look.

 

The cat can fail from overheating or contamination. Porsche would have to make that determination. Although if it was from severe overheating it is possible that the metal substrate could have physically failed. In that case you might be able to see it by looking into the cat. The cats in our cars are made from something on the order of an Aplha IV alloy. You'd have to get north of 1000C/1832F to have a thermal failure.

 

Impossible to tell from here what caused it, but if it's any comfort, I suspect PCNA will want to know why also and your dealer can't give them a brush-off. You're in Calif too, and the manufacturer is on the hook for some very long period of time with respect to everything that's emissions related. That warranty is like the one on seat belts and it's dictated by California law. Replacing one set of cats won't make them blink, but they will want to know it isn't going to happen again. And even if it does, you're protected up to ... I think 80 months or maybe it's 80,000 miles. I'd have to dig out my warranty booklet to be sure. Anyone have it handy? But PCNA isn't 'protected' in any sense and they seriously disapprove of paying for the same work repeatedly.

I don't insist your dealer isn't competent, but you might try asking for a senior mechanic to do the work this time. Three HPFP units? That doesn't sound right at all, and I suspect that doing the calibration wrong on one of those replacements could well induce contamination of the cats. I don't really know, honestly, but when an item gets replaced and then replaced again, it's in the same category as "that's racing." Well, "That's sports cars." But when it happens a third time, it's worth asking whether the people doing the work have screwed it up.

Gary

 

Gary,

You were partially correct. Per the DOT regulations, the emission components of a car are covered for 8 years or 80,000 miles, which ever comes first.

 

Thanks for the great info. I called up the service advisor and asked him why the converters need replaced, and he said that according to an internal bulletin, whenever the check engine code is read for a certain value, the dealer should replace both converters. There are sensors in the converter that went bad and raised the error code. Porsche does not explain why, and the advisor speculated that the sensor could have a design problem, so when the sensor went bad, Porsche would replace the whole converter, supposedly with a new sensor.

So...that's it, I guess. I was expecting the HPFP to go bad again originally, so maybe this is just a fallout from the bad HPFP before.

 

The converter is just a piece of hardware and is at risk of premature failure for a variety of reasons.

The converter should be able to process a bit of oil in the exhaust. (Gasoline comes with a tiny bit of oil in it anyhow.) While the oil consumption is 'high' it is not that high and doesn't burden the converter.

Besides converter temperature is available and if converter temperature climbed to a too high of level there would have been an error code reflecting that. In some cases the CEL would have been flashing to warn of pending converter damage.

I suspect the error code is related to the converter performing under efficiency and this arises because the converter is unable to store enough oxygen to process exhaust gases properly.

Have to add: If a non--approved oil was used that had elevated levels of additives that have been deemed harmful to the converters the additives could have damaged the converter.

Sincerely,

Macster.

 

Thanks, Macster. Now that I have the car back, the report from the dealer stated that I have error code DTC P0431. Bank 2 warm up cat was replaced.

So it's not both converters replaced, as the advisor told me.