Macster

You can almost eliminate the MAF by disconnecting it at the wiring harness, clearing the DTCs (even if there are none this resets all the learned fueling to the defaults) then driving the car as you did when the symptom/behavior appeared.

If the behavior/symptom gone... MAF is #1 suspect. Since these are so expensive you want to be sure though.

Be sure the oil filler tube cap is not leaking. (The original one on my 02 Boxster was leaking (I couldn't hear it but a co-worker did). My missing this leak caused me to mis-diagnose a MAF as the cause and replace a perfectly good MAF when a $15 cap was the real fix. But all worked out: The replacement MAF started acting up -- I made a better diagnosis this 2nd time -- and on a hunch I dug the old MAF out of my car parts stash and installed the old MAF. Old MAF worked just fine and it is still working just fine.)

Anyhow, get an OBD2 code reader/data viewer and prior to or at cold engine start verify intake air and coolant temperatures are close to ambient and each other. Verify neither jumps up (or down) at engine start or after as the engine's idling/warming up. If you see for instance the coolant sensor reading high the engine controller will be misled into believing the engine is warmer than it is and run a leaner mixture which can account for the behavior you observe.

Sincerely,

Macster.

RPMulli

I told you its too cold to drive the p-car out here!!!

tooloud10

The problem occurs whether the outside temperature is -20 or 100+...mine is definitely not temperature dependent.

Pac996

Check the air filter lately?
Yah sure the electronic adjust for airflow but that doesn't mean it like slower air flow.
-20 ??? You ought to be ashamed of yourself. Maybe try getting the air intake to fed off engine compartment air thats a bit warmer.

speed rII

Well, on my car this problem is almost the same. It will do it always when engine is cold. On summer this is no so much big deal, becouse engine gets really fast to this temperature.
But winter, it was -10C (14F) this morning, and it took about 10min drive to get rid of the symptoms.
All the problems wanish when engine temp is above 50C (122F)

My educated quess is the temp sensor.

And thank you Macster, I have all ready ordered Durametric.
When it arrives, I will check the sensors.

Pac996

Might try some injector cleaner. Cold makes gummy even gummier.

tooloud10

Ashamed of myself? For using my car? I don't know what some of y'all think happens to these cars when the outside temperature drops below 50 degrees, but it's simply not true.

Also, a "cold start" isn't describing the act of firing the car up at -16 degrees, like I did just this morning.

speed rII

Ok,
So I got the Durametric and tested the sensors this morning.
Maf is ok, values at idle about 37kg/s (if iremember the unit correctly)
ECTS was 7Celsius of from ambient, but I dont think this if causing the broblem
IATS was 12Celsius of
Only one fault code, "injector 1 open circuit" reset it and it did not come back.

I think I will try the injector cleaner that Pac996 suggested and see if that helps

Pac996

I hope the engine looses its chill towards running in the cold. Even if a little water or gunk ends up in an injector it can freeze things up which might be whats happened. Even the cleaner fluids don't make injectors all the way clean. There are different varietys of injectors and some of them have so many tiny passages I could swear they are meant to foul up. I don't think ethanol helps matters with the water the alcohol can hold which makes me think of the fuel like a dakari cocktail for the car going through the fuel lines

speed rII

ok, just got mine FIXED
List of things that I did
- Put back the loose injector #1 wire... (yep, my foult)
- Put some connector cleaner and oil to engine harness plugs. (that attaches to frame harness)
- Take out and cleaned the oilfillertube, seems that it had a small leak in o-ring that is on the block side. Put some engine silicon on the o-ring. (did not have new o-ring) (This one was pain in the a** to do)
- Put some engine silicon on the throttlebody seal.
- Cleaned the maf with some electrical cleaner

I used the durametric to find out the problem. There are dme setpoints in the servicemanual, and some info what could be wrong if the values are wrong.
Specs can be found on Group 0 diagnosis to 45, on the servicemanual.

Pac996

zooooommmmm!!!!!!!!!