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Old 12-20-2003, 01:37 PM
ThomH ThomH is offline
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Join Date: Dec 2003
Location: Germany
Posts: 47
HELP: air flow meter pot


I currently feel lost with my problem. I have exchanged the pot of my afm and tried to adjust it according to the describtions of different sources. It's a M103 engine of 1986.

What happend? I adjusted the trim pot of my new afm pot according to my old afm pot (131 Ohm). Then I inserted the new afm pot and rotated it in such a way that the resistance would rise directly after the idle position of the flap (flap 1mm below cylinder). A MB direction says to check for U12 = 0.2-0.5V (voltage between pin 1 and 2) with the top surface flap at the buttom edge of the cylinder. I had 0.15V. I started the engine and had to modify the position a bit to improve idle. However U12 was 6V at idle. When I rotated the pot slightly more, the engine stalled until off at about 3,5V. Hence I had no chance to set to 0.7V at idle, what Steve suggests here in this forum. However, with engine off there are 0.7V at the idle position of the flap. So at the same flap position I have a completely different resistance readings depending on engine on/off. But U13 almost doesn't change.

With EHA unplugged the engine runs just wonderful.

Do you have any idea what to do (besides keeping it unplugged)?

Thanks a lot
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