The other thing you can do is to turn the solinoids on and off with a dramatic. If turning one on and off with no difference in how the moter is running will vairify which one it is.

 

Ok guys, I'm back. I waited for the actuator to arrive, swapped it out, but alas, the problem remains. Now the CEL comes up very often. Mostly when cruising at around 80kph in third (which is right near the 3000rpm mark).

Diagnostics by PIWIS revealed some new errors:
P0301 / P0302 / P0303 - Cylinder 1-2-3 misfires
P0133 - O2 Sensor Circuit Slow Response (Bank 1 Sensor 1)
P0234 - Turbocharger / Supercharger "A" Overboost Condition (wtf is this? I'm only at 1.2bars)
P0300 - Random misfires
P0040- Oxygen sensor signals swapped, bank 1 sensor 1 /bank 2 sensor 1 (???)

 

Never seen those 02 codes but from the description check of the black harness o2s are pre cat. Also, do you have oem authentic pre cat o2s?
Chalcedon for black smoke / exhaust leaks between ur turbo and exhaust too.

 

when was last time you touched the fuel pump, (is it old design?)maybe you have a split on the hose, do me a favor and check your fuel pressure. simply attach the fuel pressure tester next to fuel filter, start the car, and see what it reads.

 

I get the P300 code as well. Only in the cold morning and I live in San Diego. Doe's anyone had this experience when starting car on a cold morning and they get the CEL? For me it's the only time I get CEL and sometime rough start. What can cause this? Thanks in advance.

 

...You want to know about "Cold" start... I live in Canada - no codes after any "Cold" start - and I'm sure our "Cold" is different from yours! This is not normal and should not be happening.

 

plugs n coils. good place to start ( looking that is )

 

Yes your cold is different. San Diego cold morning is in the 45 to 50 F.
It's not normal. Just curious why on a warm morning it doesn't happen.

@02996ttx50 Will look into that. Thanks.

 

are you running after market 1 bar wastegates? if so then your out of fuel at 1.2 bar... unless you tuned for a 5 bar or injectors...
do a proper pressure test and go from there.

 

I agree on this. Thats what it sounds like. I now do a boost test every 2 months.

 

no black smoke or leaks, I'm not sure about o2s.. the car is said to have "exhaust with 200cel sport-cats", all i know

will do. PIWIS diagnostics didn't find anything unusual with the fuel pump though, I remember we engaged and disengaged it remotely via computer just fine, but will check nevertheless.

afaik everything else is stock (apart from what I wrote). Did a pressure test, no leaks The car does run rich though, judging by the carbon deposits on the insides of exhaust tips.

 

Even though P0040 can mean different things. It can arise if the sensors return a voltage signal outside of the allowable range. The Turbo #1 sensors are wide band and operate from 0V to 2V. (The #2 sensors are narrow band and operate in the 0V to 1V range.)

To know what P0040 really means one needs access to the *full* 996 Turbo OBD2 diagnostic manual. I have an OBD2 manual but it doesn't list any P00xx codes.

Anyhow, the errors suggest an air leak.

Check the hoses/plastic plumbing/connectors/etc around the throttle body.

 

My 2003 Turbo does this on "cold" starts here in northern CA which has a pretty mild climate similar to that in SD. By "this" I mean shortly after cold start at cold idle speed the engine can run a bit rough and the CEL then comes on. Always I retrieve the same error codes: P0303, P0306 and P0300. There are never any pending codes. The engine never misfires or in any way acts up at any other times.

Not because of the misfires -- which IIRC didn't occur while I was back east -- on family business for nearly a month -- in sub freezing temperatures -- but because on the way back home an O2 sensor error came up that pointed to a bad heater with one of the #1 sensors. So at 132K miles I had all 4 O2 sensors replaced.

After the engine ran a bit better and the O2 error code was gone but the cold start misfires persisted.

More recently at I think 140K or possibly 145K miles I had the coils and plugs replaced. Plugs had about 10K miles left but the tech said while he was there he'd recommend changing them and I agreed. The coils were original.

Afterwards the engine ran a bit better. I've had the plugs changed before with no change in the engine so I attribute the improvement to the new coils.

Talked with a senior Porsche tech about the misfires and he suggested it might be a dirty/sticky injector or two. Gave me a bottle of fuel system cleaner (Swepco) to use. I used it and it made no difference.

But I figured if some's good more is better and after using up all the fuel with the Swepco fuel system cleaner in it I followed with a bottle of Techron and filled up the fuel tank then after all the fuel used up with that bottle I added a 2nd bottle and filled up the fuel tank again. Ran all that fuel out and still the misfires persisted.

Next time I take the car in I'll speak with the tech.

In the meantime I just no longer let the engine idle after a cold start. Instead after just a moment or two, after the engine RPMs dip slightly then recover -- which is I think when the DME switches the intake valves into low lift mode -- I gently back the car out of parking space and hit the road albeit of course being easy on the engine until it is fully warmed up.

That the misfires occur at "cold" start and after the DME switches to low lift mode suggests the problem is not with the fuel injectors but possibly with one or two intake lifters that don't switch to low lift mode.

 

Reporting in.

Cats were toasted. Looks like their removal positively impacted acceleration. However, I can't tell for sure since the roads are covered with ice already.

Fuel pressure is ok (3.5 bars).

After a day of driving the flashing CEL came back right at 3000rpm in 3rd.

The search continues...

 

What is your voltage running at.