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Multiple Codes, Air Leak vs O2 Sensors

Go to solution Solved by rick3000,

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The dealer has had the car for almost three weeks, and the techs are still completely baffled. They have said they could go at it and spend a few days dismantling it until they find a problem, but to keep the cost down they are taking a more detective like approaching, checking something then pondering the problem about while they do an oil changes, etc on other cars. They are waiting to hear back from Porsche in Germany and the regional rep. to see if they have any suggestions.

Apparently, after the smoke test, the car refuses to idle. The next morning they tried to start it and it runs if you rev the engine up, but at idle it dies. The car keeps triggering MAF codes, but they have checked the sensor, the wiring between the sensor and the DME, and tried a replacement DME to no avail. (and it should run without the MAF anyway) They have also checked the throttle, and a number of other things, but have found nothing. The current theory is something related to the air system, and possibly a blockage from an animal or nest. The tech said it is acting like an air leak (despite checking for that before), but they can't test for an air leak without the car being able to idle, which is the catch-22.

So for the time being I am waiting to hear what they might find, or if the rep or Porsche Germany have ever seen this issue, and have a suggestion. Has one ever encountered, heard of, or had this kind of an issue?


Edited by rick3000
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  • 2 weeks later...
  • Solution

Hi Everyone,

After 4 1/2 weeks at the dealer I have finally gotten my Boxster back, and it is perfect! I was very lucky that the dealer took a more detective like approach to keep the cost down, versus spending 3 days with in a bay and stripping it down until they found something. It cost about the same as the 75k mile service. Luckily, I had a spare car to use, however if this every happens to anyone else, now you will know what to check. Of all the things it could have been, and testing/replacing/etc the AOS, MAF, intake, throttle, DME, among many other things it was the throttle control valve. I knew it had to be something stupidly simple.

The throttle control valve is only on non e-gas cars (I believe pre-2000), and when you come to a stop it opens to provide the engine air to idle while the butterfly flap is shut. They did not replace it, it had some carbon buildup that was keeping it shut, so when the car idled it would stall from the lack of air. After some compressed air and WD40 and it is as good as new.

They found it yesterday while playing with the throttle, no one thought to check it because no one at any Porsche dealer on the West Coast had ever heard of one getting blocked like this. They also replaced a tank vent line and valve, which is what was causing the hydraulic/gas escaping sound, however that was unrelated to the idle issue. I think it also restored some lost low end torque, because on my way home it was like driving a bullet!

Lastly, when I picked it up the instrument cluster went a little crazy, until we disconnected and reconnected the battery. The mechanics had also never seen anything like this either. Enjoy the picture of the highest milage Boxster ever. I only grabbed a picture after they switched to miles, when it was in km, it was reading 999,999. Which I think may have affected resale value.

Thanks for all of the input everyone! I have had a serious case of PermaGrin all day!


Edited by rick3000
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