Editing AFM (section)

==Self Cleaning==

Self cleaning occurs for about 1 second during a 10 second period, after the vehicle ignition key is turned ON to OFF. 

The [[ECU]] must have registered exceeding 2000 RPM and Speedo sensing greater than 20 KPH for AFM to self clean. 

During the 10 second period, the [[ECU]] remains powered on even though the ignition key is turned OFF

This occurs, because the [[ECU]] uses the ignition key signal to switch on the [[ECCS]] relay.
 
The [[ECCS]] relay controls power to the remainder of the [[ECU]] circuitry and all EFI components (AFM, CAS, O2 etc). 

The [[ECU]] uses a timer in the software to count the 10 seconds, and at the end will send a 12 volt signal to pin 4 on the AFM

'''Front view'''

[[Image:Afm3.JPG]]


'''Hot Wire activated during self clean'''

[[Image:Afm4.JPG]]


Sometimes self cleaning isn't enough when the AFM stops working.

Imagine a dirty soldering iron etc where although there is heat, there are particles which cannot be burnt off.

It is suggested that the platinum wire be cleaned with some form of electrical contact cleaner.

Spraying the cleaner might not be enough in some instances (as found from personal experience) and a very gentle brushing may be required. 

Be very careful touching the wire, as it is quite thin, and can break very easily. 

It may be possible to replace this wire also.

This is the main reason why AFMs refuse to work correctly, giving inaccurate results and affecting engine running.

'''Front view'''

[[Image:Afm1.JPG]]


'''Under the cover'''

[[Image:Afm2.JPG]]



'''AFM - [[ECU]] - Description'''

*1 - 26 - Digital ground (ECU)
*2 - 36 - Chassis ground
*3 - 31 - Output signal
*4 - 12 - Air wire self cleaning
*5 - Battery power (from EFI relay)
*6 - 30 - Mixture setting

To the left is a blue calibration potentiometer.

This has a range of 15 turns from 0 - 1K ohms.

This pot doesn't actually appear to use any of the circuitry within the AFM itself but is a calibration for the IDLE. 
Factory setting for this pot is about 382 ohms (which measures 3.58 volts when the [[ECU]] is powered on).
This can be adjusted but is not recommended unless you have a wideband exhaust gas analyser.
At 2000 RPM the Air/Fuel ratio should be at stoich 14.7:1.

The [[ECU]] requires two main sensors to operate the engine.
Other components may fail and cause problems but it is still possible to keep the engine running the vehicle with a failed O2 sensor, AAC valve, Air regulator etc. even though there may be problems with fuel consumption and poor idle due to these components