FirstPorsche

I have a 1987 944S that is experiencing intermittant cold start problems. I must say that my electricity knowledge is all from the 10th grade. My Haynes manual (which does not specifically cover the "S") suggests that I check the Fuel system to see if the correct voltage is making it through the system. I bought a nice multimeter and have tested a couple of things.
1. What is V versus mV?
2. Air Flow Sensor Check - I pushed back the protective boot to expose the "terminals." I see four wires leading into another rubber boot. When the Haynes manual says to "Check between the back of terminal 9 on the connector (non-turbocharged models) or terminal 3 (turbocharged models) and a ground with a voltmeter" I am lost. I have 4 wires (which I tested anyway, see below). Which one am I supposed to check??? Also, do I touch the Red test lead to the wire itself or to the rubber boot above where the wire goes in??? The Haynes manual says that non-turbo should be 8+ volts and the turbo should be 5+ volts. I have already touched the wires to ground with the ignition OFF and get readings above these figures on all places (on the wire AND on the rubber piece above where the wire goes in) EXCEPT when I test the far right wire (standing on drivers side looking down at the sensor). This one wire, with the ignition off reads 4.5 mV.
2. With the ignition ON I tested all 8 places and get very high mV readings. All between 30 and 50 mV. Is this OK?
3. I unplugged the connector and saw the following. From left to right (standing on drivers side looking down at the sensor) there is a "blank" where the first wire came in, and then a silver plug in #2, #3 and #4. If someone could educate me as to what # terminals these all are I sure would appreciate it.
4. From what I have said so far, does this all sound OK?

If you made it this far, THANK YOU!

ahofam123

Usually when the Haynes manual suggests taking voltage readings,it means taking the voltage at a wiring harness. I know of one connection above the master brake cylinder but I believe that is for the guages, and I don't know if the air flow sensor will be located in that one. Even if you take a voltage at the sensor, I beleive that it should be close to the voltage at the connection. The values for the various sensors are located in the beginning of one of the chapters of the Haynes manual. I don't remember which chapter, but for some reason the fuel and emissions chapter comes to mind.

coupe

V = volts, mV= milli-volts

FirstPorsche

Thanks guys.

So, if I am getting a reading of 50 mV that means it is actually 0.05 Volts???

May sound like a stupid question but I want to be 100% sure of the conversion.

Thanks again.

Tom Carson

5.00 v = 5000 mV
0.50 v = 500 mV
0.05 v = 50 mV

yes 50 mV is actually 0.05 volts

<a href="http://www.frwilk.com" target="_blank">www.frwilk.com</a> has a good write up on the AFM at:

<a href="http://www.frwilk.com/944dme/afm.htm" target="_blank">http://www.frwilk.com/944dme/afm.htm</a>

FirstPorsche

Tom:

That writeup was very helpful. Those numbers are not visoble on my connector plug.