Last Try CEL

[DamageINC123]

The is my last try to resolve before I "JUST LEAVE IT". I can make my CEL come on by aggressively driving. Basically running 0-60 wide open. I have replaced the air flow sensor I have swapped the coil packs and I have replaced the plugs. Normally driving with quick acceleration but not past 6,000 will not turn the light on. The car runs perfect with no issues. The codes are 300,301,304. Mis-fire. I do not feel this mis-fire or notice anything. If it were not for the light I would have no idea there is an issue. Any thought before I call it quites. The only bad thing about the car which happens to be also one of the best things is the mileage. Its a 1997 with 30,000 miles. Sometimes not driving can be more harmful than driving. It did seem to get a little better since I have been driving it more lately. Maybe I will run another bottle of Techron through the tank.

Let me know what you guys think.

emission damaging to catalic converter mis-fire(300)

misfire cylinder 1 damaging to catalic converter (301)

misfire cylinder 4 damaging to catalic converter (304)

Edited December 15, 2009 by DamageINC123

[1schoir]

The is my last try to resolve before I "JUST LEAVE IT". I can make my CEL come on by aggressively driving. Basically running 0-60 wide open. I have replaced the air flow sensor I have swapped the coil packs and I have replaced the plugs. Normally driving with quick acceleration but not past 6,000 will not turn the light on. The car runs perfect with no issues. The codes are 300,301,304. Mis-fire. I do not feel this mis-fire or notice anything. If it were not for the light I would have no idea there is an issue. Any thought before I call it quites. The only bad thing about the car which happens to be also one of the best things is the mileage. Its a 1997 with 30,000 miles. Sometimes not driving can be more harmful than driving. It did seem to get a little better since I have been driving it more lately. Maybe I will run another bottle of Techron through the tank.

Let me know what you guys think.

emission damaging to catalic converter mis-fire(300)

misfire cylinder 1 damaging to catalic converter (301)

misfire cylinder 4 damaging to catalic converter (304)

I had a 306 CEL recently, which turned out to be an intermittent loose connection to the ignition coil of cylinder #6. It would only manifest itself after the engine was close to warmed up.

Double check your connections to the two coils and their respective spark plugs, as well as that the plugs are torqued correctly.

Not sure this will help, but it can't hurt.

Good luck.

Regards, Maurice.

[DamageINC123]

Coils and plugs on cylinder 1 and 4 have been replaced. I do get a pending code p1313 shich definitions is manufacture controled eginition system or misfire. Is it possible I getting a code by hitting redline. Does this car have a revlimiter that maybe set thats giving a false CEL as a misfire?

[1schoir]

Coils and plugs on cylinder 1 and 4 have been replaced. I do get a pending code p1313 shich definitions is manufacture controled eginition system or misfire. Is it possible I getting a code by hitting redline. Does this car have a revlimiter that maybe set thats giving a false CEL as a misfire?

My '97 Boxster has a revlimiter, and I have hit it a few times, but it has never produced a CEL as a result.

In your scenario, it certainly does sound like a possibility. Have you tried hooking your car up to a Durametric to see if it is recording Range 1 overrevs everytime that you go past 6,000 RPMs and get a CEL?

That might help you narrow it down, as the Durametric has a screen that gives you the Range 1 and Range 2 overrevs recorded and the last engine operating hour when either one occurred.

Regards, Maurice.

[RFM]

Looks like one or both cats going been shot, converter capacity too low by full open throttle and full engine regime, blinking Cel and go's out when the engine RPM drops till approx. 5K RPM. DME consider this issue as misfires as well.

[DamageINC123]

The check engine light actually blinks for about 5-10 seconds and then goes solid. Not long ago I had an issue with the o2 sensors setting off a code. Porsche has in their notes that they did something to the wires and code was resolved. Could it still be a bad read on the o2 sensors causing the comp to overcompensate for for something. If it is the cats should I just leave it alone until they get worse or is there an inexpensive way to fix?

[DamageINC123]

RFM,

When you say cats are shot which cats are you referring to, all four? Keep in mind the car has 30,000 miles on it. Could they go bad that soon?

[wvicary]

The Catalytic Convertor can easily be damaged from a misfiring engine regardless of milage.

[DamageINC123]

I have no doubt a misfire would damage the cats, but whats causing the misfire. You would think if I had a misfire I would feel it. I definitely dont think the car would be running as good as it does and still gets great gas mileage. The light only comes on when open it up and come close top redline on the tack. Even then you cant feel this misfire. It runs like it did since day one.

[DamageINC123]

I appologize if I misunderstood what RFM is saying, I cant tell if he says the cats are shot or going to be shot.

[ericinboca]

I have no doubt a misfire would damage the cats, but whats causing the misfire. You would think if I had a misfire I would feel it. I definitely dont think the car would be running as good as it does and still gets great gas mileage. The light only comes on when open it up and come close top redline on the tack. Even then you cant feel this misfire. It runs like it did since day one.

I'm not sure, but I think RFM is saying the cats are going bad and you are getting error messages as a result with the DME misinterpreting them as misfires at higher revs. Again, not sure, but I think what he is saying can be interpreted that way. If cats are going bad, it would be the primary cats - teh pnes that are part of the headers.

[wvicary]

You're going to need the Porsche tester or Durametric software to determine if and how frequent a misfire is being recorded. I DME can record a misfire that you can't feel especially at higher RPM's. Any idea what the MAF reading is at wide open throttle?

[DamageINC123]

The MAF is brand new. The Porsche dealership after having it all day came to the conclusion it was the MAF. This was after cleaning it and supposedly not being able to duplicate the problem. A few days after I got back, I got into pretty good and the light came back on. So I replaced the MAF with a new one. Still did not correct the issue.

I just went out a few minutes ago for a short ride. Running the RPM into the 5,000 and 6,000 range about 7 different times with no issue. Wound it out close to red line and the light came on. Reset the light and continued home reving it out to around 5,000 to 6,000 with no issues. **** these cars are a blast!!!