Arjan B.

Since I the day I bought my car, the engine is running smooth at cold start and idle, after driving on the road, and wait for a traffic light, about 5 minutes after the cold start, the engine is running a bit shaky, not the 'missing spark' idea, but more in the line of 'rich running or a vacuum leak symptom. When the engine is warm, after a 15 minutes, the engnine runs smooth again in idle.

The 'shaky' runing is just in idle run, not under load or cruising.

Anyone who has the same symptoms?

warmfuzzies

Arjan,

Maybe the mixture is begining to lean off as the engine warms up, much like releasing the choke on an older engine?
Mine is sometimes a little on the hesitant side when accelerating from cold (not heavy accelerating) and seems to have a barrier to break through. I just assumed it was characteristic of the car..........

kevin

robmug

Mine,after about 1 to 2 minutes, if I'm idling, does a couple of little coughs (best way to describe it). Quite cute really, and i think it is to do with the management system parameters changing as it warms through.

Adrian

Dear Arjan,
I would check the heater in the O2 sensor. It may have failed meaning that it it relying on the cat to heat it up. Most people do not know that the 964 O2 sensor uses an internal heater.
Ciao,
Adrian
964C4

warmfuzzies

Adrian,

Are the pins ref the O2 heater mentioned in your book for checking the sensor? or could you give me the quick and dirty, Think I'll go and check whilst I have time on my hands.

Kevin

Arjan B.

Hey Adrain, Back from the States! I suppose you had a great time there. Please post pics asap to show us your adventure.

Adrian, I replaced my O2 sensor in November for a new one. ith the old sensor it was the same shaking. It's just Kevin says, the 'choke' effect.
just shaking and a unstabile run from the engine in warm up phase.

Adrian

Dear Kevin,
I am having trouble reading things at the moment. You need to check the heater from the connector. I cannot remember off hand which pin it is on the connector but it gets its 12V from the DME relay. I am sure it is in the book. You could always jumper the DME relay and check that the O2 sensor gets warm. Do with everything cold so you can feel it warm up. If you are really equipped you could use a digital heat sensor probe to watch it heat up whilst not having to bend down too much.
Dear Arjan,
Even though you have replaced the O2 sensor it is still a good idea to check the circuit. The problem might be in the connector? I can guarantee not one mechanic ever checks if the heater is working.
I took 488 digital photos. I will be installing some on my web site. I think Joe W. is going to post some to the forum. Had an awesome time in both Daytona and Boston.
Ciao,
Adrian
964C4

Arjan B.

O.k. Adrian, I will check the connection and measure the voltage on the connector soon. I can be that the O2 sensor is not heated well, so different fuel mix will enter the intake manifolt.

Great that you had a nice time in the USA, I look forward to go there in June myself.

warmfuzzies

Thanks Adrian, will examine the book in more detail.

Glad you had a good time.

I'm there shortly before Arjan, and then shortly after.........SF that is.

Kevin