I have for sale a used but refurbished AFM. The Part number is 13 62 1 466 350. This was used on many of the classic BMW motors but this particular unit came from my 1989 325is. Should work with all M20 motors.
Let me tell you that this is one of the most important sensors for your engine. After 20 or so years, these units really start to send your ECM poor and inaccurate feedback. The AFM has two sensors in one unit. There is a Air inlet Temperature sensor, which provides feedback to the ECM for incoming air temp. There is a potentiometer which provides the ECM feedback voltage that is linear with the opening of the internal flap.
After many years of use, the inaccurate feedback will affect economy, poor running, poor idle, symptoms of misfire, and loss of power.
I am an electrical technician with over 10+ years experience in electronics repair, rework, and restoration. Please trust this sensor is tested with the utmost quality and standards.
Here are some photos of the process that I used to test and refurbish the unit.
I first test the temperature sensor circuit. If this is bad, the AFM must be replaced. There are no replacement parts for this. Purchase refurbished AFM elsewhere for $500, go check for yourself.
Unit is opened up and inspected for wear. This is the potentiometer circuit.
Close-up of the "resistor strip." As you can see there is severe wear along the wiper contact. Once this strip is worn away, as you can see...the car will start to idle rough, provide poor fuel economy and everything else listed above. You can also see the input and output contact coming out of the black connector. These must be refurbished too.
Entire arm assembly disassembled and all electrical contacts thoroughly cleaned.
Cleaned using special electronics cleaner, although this is not much help once the resistor strip is worn out.
Once the resistor board is cleaned, I make adjustments to the connector contacts onto fresh resistor board. I also modify the wiper contact to make contact with fresh resistor strip. None of the old wear tracks are used. Connections are now used on fresh material only.
Close up of the action. Notice the wiper contact is now centered over fresh resistor strip. Noticed the electrical contacts now make contact with fresh resistor pads. Again refurbished unit contacts only contact fresh resistor pads and strips.
Once re-assembled. The unit is tested for voltage output and drop of any feedback during the length of travel. The temperature sensor is also tested throughout its range.
Here is a graph of the linear nature of the sensors feedback. Referenced from a New AFM unit.
Photos of testing the range of the flap feedback. Flap open 0%
Flap open 25%
Flap open 50%
Flap open 75%
Flap open 100%
Once the range testing is complete. I perform one more test with an analog meter. This will show me, during the length of travel of the wiper contact, if any "spots" drop out or are not linear.
Once all is done. I sealed the unit up with silicon sealant. Electrically, these units are in near new condition. I've personally tested this particular unit on my own car and it works fantastic. I found better MPG, smoother idle, smoother power of lower RPM'S.
I see used non refurbished units all over the internet for $40-50 each. Don't trust these AFM's. They have very little life left. Don't replace your 20 year old AFM with another 20 year old one, it can be just as bad or worse. Who can afford a factory refurbished unit for $500 (per Bavauto.com.)
Unit is SOLD, Please Contact me for refurbishing your AFM or MAF. You can receive a discount in the following ways:
Provide me with your "suspect" AFM and receive a discount.
Willing to entertain for trades. Especially looking for a well working Idle Control Valve. Also looking for a roof rack.
For those looking to have your AFM refurbished. Please PM me and I can provide you a quote for this service.
Note: for older AFM's and MAF, I will include an additional service free of charge. This service is to ground the wiper contact arm to the grounding pin in the connector. This provides a more reliable and stable feedback and is the reason why the later versions implemented a ground in the design.
Thanks
Greg
Let me tell you that this is one of the most important sensors for your engine. After 20 or so years, these units really start to send your ECM poor and inaccurate feedback. The AFM has two sensors in one unit. There is a Air inlet Temperature sensor, which provides feedback to the ECM for incoming air temp. There is a potentiometer which provides the ECM feedback voltage that is linear with the opening of the internal flap.
After many years of use, the inaccurate feedback will affect economy, poor running, poor idle, symptoms of misfire, and loss of power.
I am an electrical technician with over 10+ years experience in electronics repair, rework, and restoration. Please trust this sensor is tested with the utmost quality and standards.
Here are some photos of the process that I used to test and refurbish the unit.
I first test the temperature sensor circuit. If this is bad, the AFM must be replaced. There are no replacement parts for this. Purchase refurbished AFM elsewhere for $500, go check for yourself.
Unit is opened up and inspected for wear. This is the potentiometer circuit.
Close-up of the "resistor strip." As you can see there is severe wear along the wiper contact. Once this strip is worn away, as you can see...the car will start to idle rough, provide poor fuel economy and everything else listed above. You can also see the input and output contact coming out of the black connector. These must be refurbished too.
Entire arm assembly disassembled and all electrical contacts thoroughly cleaned.
Cleaned using special electronics cleaner, although this is not much help once the resistor strip is worn out.
Once the resistor board is cleaned, I make adjustments to the connector contacts onto fresh resistor board. I also modify the wiper contact to make contact with fresh resistor strip. None of the old wear tracks are used. Connections are now used on fresh material only.
Close up of the action. Notice the wiper contact is now centered over fresh resistor strip. Noticed the electrical contacts now make contact with fresh resistor pads. Again refurbished unit contacts only contact fresh resistor pads and strips.
Once re-assembled. The unit is tested for voltage output and drop of any feedback during the length of travel. The temperature sensor is also tested throughout its range.
Here is a graph of the linear nature of the sensors feedback. Referenced from a New AFM unit.
Photos of testing the range of the flap feedback. Flap open 0%
Flap open 25%
Flap open 50%
Flap open 75%
Flap open 100%
Once the range testing is complete. I perform one more test with an analog meter. This will show me, during the length of travel of the wiper contact, if any "spots" drop out or are not linear.
Once all is done. I sealed the unit up with silicon sealant. Electrically, these units are in near new condition. I've personally tested this particular unit on my own car and it works fantastic. I found better MPG, smoother idle, smoother power of lower RPM'S.
I see used non refurbished units all over the internet for $40-50 each. Don't trust these AFM's. They have very little life left. Don't replace your 20 year old AFM with another 20 year old one, it can be just as bad or worse. Who can afford a factory refurbished unit for $500 (per Bavauto.com.)
Unit is SOLD, Please Contact me for refurbishing your AFM or MAF. You can receive a discount in the following ways:
Provide me with your "suspect" AFM and receive a discount.
Willing to entertain for trades. Especially looking for a well working Idle Control Valve. Also looking for a roof rack.
For those looking to have your AFM refurbished. Please PM me and I can provide you a quote for this service.
Note: for older AFM's and MAF, I will include an additional service free of charge. This service is to ground the wiper contact arm to the grounding pin in the connector. This provides a more reliable and stable feedback and is the reason why the later versions implemented a ground in the design.
Thanks
Greg
