Karl S

I installed a TRG Unichip a few years ago on my 99 996 C2. The car has run fine for 3 years with over 100 track days in that time.

However, recently I have had a problem with reoccuring check engine lights. The first one
was fixed by my dealer under warranty and they said it was caused by a cracked oil separator. They told me this was a fairly common problem on 996s.

I no sooner got the car back and took it to VIR only to have the check engine light come on again within a few laps during the first session, this time accompanied by an oil leak.

I talked to the dealer on Thursday and they said a vacuum hose to the oil separator was ruptured. But Friday they called and said there is $2700 worth of exhaust gas recirculation and wiring harnesses that have melted and must be replaced. They are claiming that it melted because the Unichip was running a richer mixture and caused the exhaust gas to be hotter than the design point for these hoses. Therefore, they aren't going to cover the repair under warranty.

Does this make sense? I'm going to ask to get all of the parts they replaced returned to me because I want to see the damage. It doesn't make sense to me that I was able to run with the Unichip for almost 3 seasons without a problem and all of a sudden it's melting hoses.

It also seems pretty coincidental that this all happens after the repair of the oil separator. When the check engine light came on at the track at the VIR event, I disconnected the Unichip and inserted a bypass plug to run with just the stock ECU. I reset the check engine light by disconnecting the battery and then continued to drive the car, even though the check engine light would come back on and it was down on power since the ECU was in limp mode. Could it be that running the car hard in limp mode rather than the Unichip is what caused the exhaust gas to overheat?

I'm sure my chances aren't good to win an argument with PCNA since they know about
the piggyback but if I believe it was something else that caused the problem and not the piggyback chip, I'll at least make a hell of a stink before I pay for the repair.

996FLT6

Hi Karl. I have the Unichip as well and and I do quite a few DE's a year and I'm confused why would dealer/service would say that's the problem. With just stock-exhaust is already hot so how much hotter did they say to get it to meltdown. If it were me I would get a pyrometer and measure temps on the exhaust and compare to one that is stock and ask the dealer what is the tolerance level of those lines and go from there. Seems like for something like that to happen yu'll need flames coming out the pipes to get it to melt something. I done exhuast/intake and dual map Unichip-what hp figures did you get? It sounds riduclous to me that whatever is around the exhaust is that fragile. Regards. Mike

Sloth

Sounds a little suspect to me. I always thought that a rich condition would run a bit cooler than a lean condition, or is that just with turbos. Probably a combo of conditions that they would put off to the Unichip. I would also think that running hard in limp mode did not help.

TrackJunke

33 track days a year....where do you find the time? Who do you do them through? Where do you live?

Karl S

I live in the DC area. I mostly run with PCA but some with other groups like NASA and CarGuys. My home region is Potomac but I run with a number of other regions as well, esp. NNJR. I've done at least one event per month since a year ago March. I'll probably end up this calendar year with close to 60 days of track time. I drive at Summit Point, VIR, Mid-Ohio, Watkins Glen, and Road Atlanta.

Unfortunately, the check engine light problems have caused me to miss 3 tracks days already and cancel out of another event next week, because I'm not sure my car will be ready.

TrackJunke

Well if I had a hat on, it would be off to you. I wish I could do that much track driving.

Ed Newman

I'd agree that a rich condition would typically yield a cooler engine. It is way too much of a coincidence that they just worked on that exact area of the car. I am not that familiar with these engines, but typically any EGR equipment is all metal as it has to handle exhaust gases at 500-1500 degress. What exactly melted? Hypothesizing here... something was improperly installed and came in contact with an EGR component at 1000 degrees that it should not have.. i.e. hose, and melted. I personnaly would bring in the district service rep before any repairs were done, completing the repair first give the delaer the opportunity to make a prior mistake dissapear. I've seen plenty of 996's overheat during DE events where the temp in the shade was over 100 degrees... no melted hoses there. Its just all seems to coincidental. My $ .02

Karl S

I went by the dealer this morning and talked extensively to the tech that is doing the repair. He showed me the damaged parts, which include the alternator wiring harness, a breather pipe, and several hoses than connect to the oil separator.

The air injection system is definitely running too hot, because it melted a hole in the breather pipe (which is plastic, what's up with that?) and the exhaust gas escaping from the pipe then melted the other components. About $2700 in repairs, including over $1000 in parts.

I still don't believe it was the piggyback chip that caused the problem, but I am at a loss to explain why the exhaust was running so hot it melted the breather pipe. Given that I have a piggyback installed, I guess I am guilty until proven innocent.

Greg Fishman

Karl,
I don't have the mechanical aptitude to agree or disagree with the dealer but you might want to read this from Steve Weiner's website.

<a href="http://www.easystreet.com/~porsche/1aa.html" target="_blank">http://www.easystreet.com/~porsche/1aa.html</a>

Here is the quote that I found interesting

"Under Federal Antitrust Laws, the use of parts or accessories that were not purchased from and installed by the Dealer do not affect the vehicle's warranty. Manufacturer's and their authorized representatives, may not condition a warranty on the use of their own parts or service, unless the parts or service are provided free of charge. Also, they may not refuse to honor a warranty unless they can show that an aftermarket part or accessory is the cause of a particular malfunction otherwise covered by the warranty."

Joe@Fabspeed

Hi Karl

Like others have said.... any engine that runs richer and with more fuel always runs cooler and the exhaust gas temperature is therefore cooler as well. Its irrefutable and axiomatic.

Refuse to pay for it as Porsche has a warranty issue ( cheap plastic EGR pipes?- clogged 993 EGR passageways) and there are going to make more $$$ on you paying privately VERSUS Porsche warranty covering the repairs. The dealer is also "seeing your RACECAR and seeing its modified and therefore your are responsible.

It doesnt matter if you have bolt-on performnace parts nor how many parts you have on the car......they cant refuse warranty UNLESS they can prove the aftermarket parts caused the precise problem. Have them replace those plastic pipes and put a heat shield around them......maybe you can disconnect the pipes.
Good luck.....hope to see you at the racetrack!
joe

Given that they are "mistakely guessed" that the engine running richer....'caused the ehaust gas to burn hotter and eat through the plastic hoses is horsecrap!" <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

Karl S

Thanks for the responses. Armed with the info from the SEMA site, I plan to take another pass at the dealer tomorrow and failing that will escalate to PCNA zone level.

It was clear from my conversation with the tech this morning that he is just guessing about the chip causing the problem. They don't have any measurements that the car was running rich. He wasn't even aware that the piggyback was disconnected from the DME when I brought it in. When I asked him if the aftermarket cats could have caused the problems, he said it was possible but I know that is bunk because the EGR pipe is extracting air way before the cats. Infact it is tied in the head as far as I can tell. I just haven't been able to determine if it is on the exhaust or manifold side of the head.