Matt O.

My friends 2002 Boxster S popped these codes. Associated symptoms include idling rough when cold, white smoke out back when you turn it on for first 10-15 seconds, rough start (low RPM on start, have to his throttle or else it will die).

Any ideas? I'm a 944 guy, these new Boxstere are Greek to me.

Thanks a lot in advance.

Matt O.

Note: we cleared the codes and CEL is out, car is warm so it is not popping the CEL yet. We will see if it does it again when it's cold.

Macster

What odor does the 'smoke' have? Any hint of anti-freeze? Unlikely but I thought I'd ask. The engine smokes because it is cold and not being run enough to warm up to full operating temp. But if you smell anti-freeze your friend's engine is sick and needs immediate professional attention.

If the check engine light was not flashing then the misfires are not the kind that put the converters at risk, that is to say unburned fuel is not being fed to the converters.

This suggests the coils are not at fault, that the misfires are due to another problem. I note all misfire codes point to the #2 cylinder bank. This of course suggests the problem is not a common problem between the two cylinder banks.

One possible cause is something is wrong on that side with the fuel supply and those cylinders are running lean. Now you might think the error codes for a something related to fuel enrichment at its limit would be present but if the engine is cold, cold enough it is not yet ready to run in closed loop mode, a fuel enrichment error might not have been detected and or have been present long enough to be logged.

Generally though a fuel line doesn't go bad on its own. Was anything done to the car recently?

It is rarer but I have encountered a case where a bad MAF caused misfires on one cylinder bank only.

If your friend is willing the MAF can be disconnected at the wiring harness connector and the codes cleared and the engine started. If the MAF was responsible you should know it by the absence of the symptoms.

Be careful to avoid static discharge to either a pin/socket of the MAF connector or a pin/socket of the wirining harness.

With the code reader if it supports it monitor the coolant and intake air temps upon cold start. Both want to be close to one another and both want to be close to ambient. If the coolant temps sensor or the intake air temp sensor (a function of the MAF) is bad the DME is not getting the news the engine is cold and will not supply a rich enough mixture. The engine can misfire and this is a lean misfire and the CEL probably won't flash.

Sincerely,

Macster.

Matt O.

Wow. Lots of good data. Yes my scanner can view engine parameters, including coolant and intake temps. I will trouble shoot with him this week and try to figure it out. Unknown as to the "flavor" of the white smoke -- I was not there to see it. If it happens when I'm there, I'll check to see if it has the coolant smell.

Thanks.

logray

If one bank is suspect, could be the variocam actuator gone south. A gentlemen over on RT.org recently had a very bad actuator causing all sorts of misfires. Although, you would probably have variocam codes if that were the case.

Macster

VarioCam solenoid or actuator is certainly a possibility.

While one would think if the VarioCam system was the cause acting up enough to cause misfires that a VarioCam related error code would be present.

But my WAG is not necessarily.

While when the solenoid in my Boxster's acted up, and the only error code I pulled was related to the VarioCam system, I observed the fuel trim on that bank reading quite differently from the other side's fuel trim. The DME was trying to adjust the fueling of the one bank to compensate for the VarioCam system's failing.

Had I been driving the car a bit differently this fueling adjustment might have produced an related error code *before* the VarioCam code was stored.

Or the fueling adjustment might have resulted in misfires had the failing been more severe.

Hard to say.

But your idea that it could be a VarioCam related problem is a good one.

Sincerely,

Macster.