Question about Porsche 944

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I have Porsche 944 1985 2.5L.When you Start the engine run smoot in low idle,w/out the airflow sensor, when I plug-in the sensor the motor cuts off.Can you help me with this problem. Alot of mechanic tells me it is the computer ECU or DME they call it defferent. some are ECU some are DME.

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  • asaabad Sep 28, 2009

    It is brandnew airflow sensor. Do I have to adjust the adjustment knob or screw? please work with me with this problem cause my car is been stock in a place I want it run so I could use it going to church every sunday. thats the only I used my car and I love to driven it once in a while.

  • asaabad Sep 29, 2009

    Okey,Before this happened the car is running smoot. my son over heat the car and I take it to the mechanic, they take the head to the machine shop for resurpace the head and tested for leak and they said there is no leak the head is just great (good). Then they put it together,and tourke the head. they start the car but dont want to start. then they check the sparplug its dumping to much gas so they unplug the airflow sensor in its running smoot in low Idle when they plug in the airflow sensor the motor cuts off.and the sensor is all mist-up for doing the adjustment. I change the airflow sensor Brandnew and still the same, when you plug in the sensor the engine cuts off. May be you could help me now. and thank you for your kind and consederation, and good bless youin so manyways.

  • asaabad Sep 29, 2009

    thi is my Fax number832-932-1567 and also mycell #713-775-3646

  • asaabad Sep 29, 2009

    Yes. this is my Fax number ; 832-932-1567, Please sen it to me how to check the wiring and the data of the sensor thank you and God bless you and your Family.

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REPLACE THE AIRFLOW SENSOR.

Posted on Sep 29, 2009

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Well okay if you have the mass air flow sensor unplugged while the cars running and you plug it back in it will stall because the ecu (computer) gets stunned with the data signal coming from the sensor and it try to go from limp mode or base setting to the measurement of air that itis now seeing coming from the sensor and causes the car to stumble or stall.

now that we now that is normal and would happen to any car with a mass air flow sensor. what it the issue? why did you have it unplugged? does the car no run right when it is plugged in and start it after it is plugged in? please let me now what started all of this and if you have any codes in the ecu (computer)? check engine light before you started unplugging the mass air flow sensor?

Posted on Sep 28, 2009

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  • michael schultz
    michael schultz Sep 28, 2009

    i really couldn't understand what you were saying other than it is a new mass air flow sensor! do you have a multimeter and know how to test a electrical circuit? if i am going to help you then you will need to know how to do this and you may need a laabscope to be certain. but might be aable to get around it. but you need to anwser my question i asked in my last post. i need to know this stuff so i can have an ideaa of what is going on with the car. like how did it start why did you replace mass air flow sensor how did it run? please work with me here and i wwill be happy to help!

  • michael schultz
    michael schultz Sep 28, 2009

    no there is no adjustment! the ecu/dme does all the adjusting by looking at all the data from the sensors . if you like and you have a fax machine ican send you the test procedures for the mass air flow sensor and how to check the wiring from air sensor to ecu/dme. i need a fax # and i can send it to you tomorrow!

    if not and you don't have aa meter than you will be way bettr off taking it to someone that does and knows. i can help you but you need to be able to test things! let me now i will help you as muc as i can.


  • michael schultz
    michael schultz Sep 29, 2009

    okay when i get to the shop tomorrow i wil get it together and fax it to you and mybe give you a call

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  • Master
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At idle, the engine is running independent from the air Flow sensor. The air flow sensor only takes part when it is above the idle set point to control Fuel: Air ratio.
When you plug in the air flow sensor at this point, it supposes to give no value so the ECU didn't give anymore Fuel to match up with the value from the air flow sensor according the predefined value in its ROM look up table. But it did because the air flow sensor actually did give some value at this point. Therefore Idon't think the problem with the ECU or DME, but the problem with the Air flow sensor gets gunk up inside. Try to clean it first. Basically the sensor reacts and measures its' air flow "door", a metal flap opening wider when more air is being sucked. Anyway, sometimes through age and a worn mechanism, but more likely gunk getting in where the door hinges of the metal flap. You need to take it out, turn up side down and spray really good Carburetor Cleaner to get off all the gunk. Good luck.

Posted on Sep 28, 2009

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