87 190e 2.3-16 Air Flow Meter potentiometer adjusting high idle

Car warmed up, the idle will stick at 2200 rpm after revving. Adjusting the AFM potentiometer counter (anti) clockwise lowers the base voltage and corrects this.

Category:

Science & Technology

Tags:

• mercedes
• benz
• bosch
• cis
• air
• flow
• meter
• afm
• potentiometer
• adjustment
• high
• idle
• 87
• 1087
• 2.3-16
• 16
• valve

[rw0584]

What are you adjusting? The attachment position of the potentiometer? I have never seen this before for adjusting idle speed. How is the potentiometer used in adjusting idle speed? I thought that it was for enrichment when coming onto the accelerator.

[FE3tMX5]

@rw0584 Yes. The rotation of the pot is directly related to the position of the air flow meter flapper. This is what tells the ECU how much air is going into the engine so it can send the appropriate amount of fuel. If the pot is out of adjustment, it can cause this high idle. The hex head in the AFM (lambda screw) is for the idle fine tuning- but in this case cannot fix the high idle.

[airbusA5000]

what is the thing that looks like there is brake lines leading into it, above the airflow meter? could you tell me what that is? thanks

[FE3tMX5]

@airbusA5000 Fuel distributor for mechanical fuel injection. Yes, they had it in 1987. ;-)

[airbusA5000]

@FE3tMX5 thanks, its just because i have a 190e also its a 93 i love it who doesnt love there 190es lol, i was wondering what it was, thanks, do you have pics or videos of your car?