CEL's with hesitation

[thtabe]

Hello all,

I got a CEL on the way home from work today and they are listed bellow. I would appreciate any input on where to start. Its a 2001 2.7L with 82,000 miles and the symptoms that came with the light were massive loss of power and hesitation.

P0102 Porsche fault code 115 - Mass air flow sensor

below limit value

P0107 Porsche fault code 299 - Ambient pressure sensor

below limit value

P1126 Porsche fault code 356 - Multiplic. mixture adapt.

lower load range B.1:

P1133 Porsche fault code 358 - Multiplic. mixture adapt.

lower load range B.2:

I can clear the code and drive the car with the hesitation and loss of power for some time (25 miles) before the CEL comes back.

Thanks for your input in advance.

Tarry

[Rui725]

I believe your mass air flow sensor is shot. (i maybe wrong, still a boxster newbie :o )

search for mass air flow and you should get a lot of topics on this issue.

from what i've read there are two ways to go about this:

1. take out the sensor and clean it

2. replace it with a new one.

visit

http://mike.focke.googlepages.com/mikespor...boxsterwebpages

this page has a lot DIY instruction.

[thtabe]

I have done the cleaning already and it did not do much if anything for me. It’s the ambient pressure sensor code that has me stumped. I have not seen this one before and the research I did on it last night was vague at best. I tend to agree with the MAF being bad but was hoping there could be some thing less expensive I was over looking.

[RFM]

Cleaning brings nothing on a faulty MAF, only a replacement can help. The ambient pressure sensor (barometer) should be located inside the DME and is not a common fault but can happen, are you sure about the codes and the diagnostic tool?

[thtabe]

I am as sure as I can be about the codes and diagnostic tool. I have a new Durametric tool and software on my laptop. As for the pressure sensor I seem to recall an issue on one of the boards where this was a problem and I can not find the posting now. As I recall it was a fairly random occurrence and was cleared for the poster with out reoccurrence. I really dont what to pay for a new DME! I guess its time to check the part number on my MAF and get to ordering. Any idea who has the best price these days?

[ericinboca]

I am as sure as I can be about the codes and diagnostic tool. I have a new Durametric tool and software on my laptop. As for the pressure sensor I seem to recall an issue on one of the boards where this was a problem and I can not find the posting now. As I recall it was a fairly random occurrence and was cleared for the poster with out reoccurrence. I really dont what to pay for a new DME! I guess its time to check the part number on my MAF and get to ordering. Any idea who has the best price these days?

On the DME, I was just talking to a DME "doctor" yesterday. He told me he has seen a few 986 DMEs have some issues. I think he would tell you to have your DME reflashed before you take the plunge of replacing, either with a new one or a used one.

[thtabe]

What does a DME doctor do? I did not think DME problems were common. Are there DME performance mods?

[ericinboca]

What does a DME doctor do? I did not think DME problems were common. Are there DME performance mods?

A DME doctor can do some bench testing on a DME, and in some cases, isolate a hardware problem, and potentially repair. The guy that I am working with at the moment, while he seems extremely knowledgeable and has fixed a CDI unit out of a 83 SC for me, said he can only do limited bench testing on more modern day DME. He can also reflash it with the unit info, etc.

Yes, DME problems/failures/faults are pretty rare, but what I was trying to say was, he has seen lately, four or five Boxster DMEs come to him with problems. I think that DME issues are so rare, that getting four or five in the last 6 months is a lot to him.

I do think I have a DME problem, but only because it has been repeatedly exposed to excessive heat under track conditions and with heat shield and insulation missing that should have been there to protect it. Further, I have largely eliminated all the other possible causes before turning to the DME. In your case, I think the advice you have thus far is spot on - replace the MAF, and see what happens.

The are performance reprogramming flashes lots of compnaies make and sell for the DME.