Re: Where ...

Hi everyone, I've been reading this board for quite a while, but have never posted before. I'd like to thank you all as it has been really helpful in getting my 2001 Boxster in better shape. However, there is still one issue I haven't been able to figure out. It's a long story but I'll try to make it short. I hope you can help me.

I bought the car 2 years ago for a decent price knowing it had a few issues, thinking I would be able to fix them. One of these issues is the engine running very rough when cold. From a stand still, if I press on the accelerator more than half-way during the first 10 minutes of turning the car on, it will lose power and backfire. It does this even in neutral. When the engine is warm, all of these issues go away.

I took the car to several different shops, and none of them could fix it. They ran smoke tests to check for vacuum leaks, checked fuel pressure, replaced the MAF, temp sensor, AOS, spark plugs, ignition coils. One of the shops discovered it had hollow catalytic converters, and that the ECU might have been tampered with. I sent the unit to ecudoctors.com and they replaced it with a new one. After I installed the replacement, the car runs better than ever when the engine is warm, but still stalls when cold.

I don’t know what else to do. Could the hollow catalytic converters be causing this? Anything else I should check? I have spent what I would consider an inordinate amount of time and money trying to fix this and I still can't get it to work properly. My excitement about having this car has almost disappeared now that it's turned into a money pit

As soon as I saw that, I thought, "O2 sensors." Are they there? (Four: one each before and after the two cats.) If so, they are probably either "confused" because of the cats not having their internal materials, or they've (at least one) gone bad. You should first absolutely determine if the cats are indeed missing their innards, and install functioning ones if so.



Edited 1 time(s). Last edit at 06/08/2013 08:53AM by Laz. (view changes)

The pre-cat sensors are definitely there, and the ECU was programmed to ignore the post-cat sensors. Is there an easy way to verify if the cats are hollow other than taking apart the exhaust?



Edited 1 time(s). Last edit at 06/08/2013 11:17PM by kskertchly. (view changes)

When the car misfires it stores code(s) indicating which cylinder(s) backfired. The approach to diagnosis is different depending on whether it is isolated to one cylinder, one bank, or all cylinders.

That said, a common problem in these cars is cracked ignition coils. Does the problem get worse in the rain?

There are no error codes being stored. As I mentioned, I replaced the ignition coils. The problem does not get worse in the rain.



Edited 1 time(s). Last edit at 06/08/2013 11:16PM by kskertchly. (view changes)

... are you located?
Does your State run smog tests?
If not you can convert your car to RoW and eliminate the secondary air injection system which by what you describe in your symptoms could be the rough-when-cold problem.
Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

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Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

I'm currently in Austin, TX, but I bought the car in Mexico and I plan on going back soon. I'm not sure if it's a ROW version because the invoice says it was imported from the USA. I looked under the car, and I only saw 2 catalytic converters, instead of the 4 I thought it was supposed to have. If I'm not mistaken, it only has what would be considered the secondary cats in the US version. Is this normal or did the previous owner do something shoddy? If this is normal, would it be a valid test to remove the catalytic converters and the remaining part of the exhaust to see if the issue persists?

I told the ECU guys about the hollow cat issue so I think they programmed the replacement accordingly. According to them: "We did what we call a ROW conversion on your ECU where the 2ndary Air Injection is turned off and the 2post cat O2 sensors are ignored".

Thanks,
Kenneth



Edited 1 time(s). Last edit at 06/08/2013 11:17PM by kskertchly. (view changes)

at engine start and for a while afterwards.

The backfire through the intake is a sign the engine's running too lean. One cause of this is the DME is getting a false and too warm temperature and is not adding enough fuel. Once warm the temperature supplied it close enough to the real temperature and the engine runs ok.

Get an OBD2 code reader/data viewer and before you start the engine from dead cold and view/monitor the intake and coolant temperatures from before engine start, at engine start and after engine start while the engine is running and warming up.