Can anyone give me some insight of a specific rule

#1 The stock air flow meter plastic lid may be opened and a slight adjustment may be made to the internal components to allow proper electrical contact, away from a worn groove.

I am sure ther is a reason for this rule but I have no clue what it is. Any help would ba appreciated.


Read this Note the discussion of grooves worn into the semi circular copper strip


Thanks Ranger. I was thinking is was some kind of performance trick, but it is simply a easy way to fix a worn meter.


Do some searching here re. AFMs and you’ll find a thread that chronicles my year long fight with engine management problems. It turned out the problem was that my AFM spring had been loosened, a ghetto solution that is supposed to allow more air flow. An AFM that is working precisely as Bosch intended is a treasure.

When I was young and didn’t know any better I let a couple people dick with my AFM spring. That led to a tough year where I did all sorts of wild shit trying to fix possible causes of my engine generally running like crap at WOT. If you have an AFM that you know for absolute fact has never been screwed with, guard it like a virgin daughter. Most engine management “performance tricks” are bad ideas because we don’t know what we don’t know.


i just bought a brand new one from ECS tuning. it was $489 but they will refund you $70 if you send them back your core. so actually its a rebuilt one by Bosche


Maybe it was rebuilt by Bosch. A couple months ago I read a thread by some AFM obsessed guy. He talked about his struggles with reman AFMs that were not calibrated correctly.

I talked to a guy (different guy) a couple years ago at e30tech that created a small business rebuilding AFMs. He’s come up with a calibration process. I tried to get him to go for the idea of calibrating a bunch of our AFMs w/o going thru the trouble of making them all pretty. He wasn’t up for giving much of a discount tho. Some searching at e30tech will find the guy.


Read this Note the discussion of grooves worn into the semi circular copper strip[/quote]

Wow, great thread! Thanks for the pointer.