Air Flow Meter's temp sensor resistance?
 

Recently my car runs abnormally:

The engine shuts off in traffic jam suddenly. It is hard to startup again. Normally it takes few try to start up. Then idle rough. It will back to normal when driving in certain speed / on a highway. So I guess something bad in air temperature sensor inside air flow meter... While cool air coming through the sensor, it gives a normal signal. <-- this is all what I guess.

So I go through the AFM test on Clark's Garage (took APM out with a 9V battery). The output voltage is smooth and proper. However, ohmmeter reads 0.7 (engine hot) and 1.1 (engine cold) which is lower than suggested 1.45 - 3.3 k-ohms of Clark.

Do the shutting off and rough idle issues casued by bad resistance of AFM ?? If so, anything I can do before purchase another AFM ??

Thanks

Kay

According to these charts, the later AFM uses different values than the early ones. It seems that your readings might be OK...


http://forums.pelicanparts.com/uploa...1688663903.jpg

Shutting off and rough idle issues can be caused by a plethora of issues. First thing I would do if the issue happens again is jumper the DME relay. Build and keep a jumper in your glove box.

Glad to hear you have been on Clarks Garage. Did you see the engine troubleshooting section? One of the first things listed under a warm no start is DME relay, so thats what I suggest you try. Testing it isnt going to yield the data you need since these can fail intermittently when it gets warm. Only way to confirm is to jumper it and see if the issue resolves.

I mean, you could test it, but it may test good, and then test bad when the car dies, although testing it on the side of the road will be difficult.

Other possible things to check is DME temp sensor, TPS, injectors/injector harness (issues presented when warm), among other things.

Mine is 944 S2 (3.0L) Is it different than Turbo??

Thanks for reply.

I have already replaced DME Temperature sensor (the blue plug on engine block) and DME relay replaced by a Focus 9 solid relay. When the engine shut off / no start, I have tried switching back to the old (spare) DME reply but no help.

Couple month ago I did a test on AFM. At that time the temperature resistance matched Clark's suggested value, which was 1.45 k-ohms in winter time. However, now value drops to 1.1 during summer. That make me suspect a bad AFM...

Now I am taking out the AFM and go through the test again...

I take the AFM out. Just see that the part number is 028203027 (made in France), instead of 028203029. Is it a difference??

http://forums.pelicanparts.com/uploa...1688711288.jpg