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How To:- Correctly set up your Air Flow Meter.

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This guide will show you how to correctly set up your engines air flow meter.

As standard there is an anti tamper bung fitted over the top of the idle mixture adjusting screw. If your afm has this bung still in place then you may not need to set up the air flow meter. However if this bung looks like it has been removed and replaced it is recommended that the idle mixture setting is checked.

Tools needed - Vernier caliper, philips/pozidrive screwdriver.


Firstly locate the air flow meter and look for the idle mixture screw location -


Now you need to locate the mixture settings code.

This code is a number that is stamped into the body of the afm, close to the mixture screw.


The code is used to adjust the mixture screw back to factory settings if needed.

Once you have located this code you need to find out the measurement needed to set up the afm mixture screw.
This is done by adding a number 1 and a decimal point to the code.

For example, a code number of 49 will be 14.9mm, a code number of 83 will be 18.3mm, a code number of 27 will be 12.7mm and so on....

This afm has a code number of 77. Once we add the 1 and decimal point to this code we end up with a measurement of 17.7mm.
Now we have the correct measurement we need to know what the screw is currently set at. Using you vernier calipers depth gauge measure from the top of the screw head to the top of the hole casting.



As you can see this one is out a little bit so we need to adjust it accordingly.

If the measurement is too high the adjusting screw needs to be unscrewed by turning it anti clockwise. If the measurement is too low then the screw needs to be screwed in by turning it clockwise.

Tip - Screwing in the adjustment screw richens the idle mixture and unscrewing it leans out the mixture.

Simply adjust the screw a bit at a time, checking the measurement with the caliper as you go.





















That's better.

Once you have set up the measurement to the requred setting then reset the ECU by pulling out the 'EFI' fuse in the engine bay fuse box for 5 minutes.


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