Help please, anyone :(

[Jem]

I know the idle mixture is adjusted by the screw on the AFM, but I have a couple of questions about the screw itself.

Firstly, I take it, it is the brass flat head screw which is covered by a red plastic cap (about 9mm in dimeter)?

Secondly, does it reach a stop when fully screwed in or out. As mine just turns and turns and turns!

I'm having the mixture set on Thurday by my local garage, as it failed the MOT with a CO reading of 5.165%

[Jem]

Anyone?

Also, are the 1.6 M40 and 1.8 M40 AFM's the same part, as I have access to a 1.6 M40 AFM if I need a new AFM.

[Jem]

No one got a clue then

[eko]

pretty sure its meant to just keep turning,came across this a couple of years ago on a 318i.

Ive inter changed between 1.6 and 1.8 AFM and it worked fine!

[jonbuoy]

If you keep winding this screw in it will over stretch the coil spring inside the AFM!
As i told you before, get it done on a CO metre otherwise you will be looking at getting another AFM for it because you did'nt take advise!

[Jem]

If you keep winding this screw in it will over stretch the coil spring inside the AFM!
As i told you before, get it done on a CO metre otherwise you will be looking at getting another AFM for it because you did'nt take advise!

Thats exactly what I am doing! I'm trying to find out if the AFM could be knackered, and there for sorce another one before it goes into the garage tomorrow!

[Jem]

Well to conflicting anwers there.

[eko]

pretty sure its meant to just keep turning,came across this a couple of years ago on a 318i.

Ive inter changed between 1.6 and 1.8 AFM and it worked fine!
_________________

what i meant was,on my old 316i it had a few running problems,whilst playing about with it i started playing with this screw,which just kept turning with what felt like no resistance.

Ended up changing the AFM in the end thinking this was the problem(but still didnt work).

Hope this clears up confusion in my last post!

[Jem]

Seems a very poor design if by over adjusting the screw you can damage the afm.

[Martinaston]

All the meters i've seen use an allen key to adjust the screw

I know they originaly came with a (red) plastic anti-tamper plug in the top, are you sure the brass screw is not a similar thing ?
You may have to pull it out to get at the allen screw underneath, Thats your choice though, if i'm wrong you may balls up the meter

With the allen screw it stops turning at the bottom (fully closed) and is normally set about three turns anti-clockwise from the bottom.

[Martinaston]

You can't dammage anything below it as all it is is a plug, kind of bleed screw thing

[Geeman]

Is that 3 'full' turns...?

I thought they were allen headed screws too. Mine was on my Sport and 318iS...

Giles.

[Jem]

Thats what I've read on here about it being an allen screw, not a flat head. Mine has a red plastic cap, covering a brass flathead screw. I did wonder if the brass screw was another tamper proof cap, and under that is an allen screw for the adjustment.

[Martinaston]

About that
You can either pay to let someone do it at an MOT shop or you can clean the plugs then run the car for a while (few days) and then see by the condition of the plugs if its running rich (wet plugs) or lean (hot, brown plugs).

[Martinaston]

If you pull the allen screw out it's just a shaft with a bit of thread at the bottom and a couple of holes for the air passage so i can't see how the brass screw keeps turning

[Jem]

It's going in tomorrow to have the CO adjusted and a MOT issued. The plugs are spot on and the car runs PERFECTLY, and the MPG is good too. Also when I did turn this screw a GOOD few times, the running on the engine remained exactly the same.

[Martinaston]

Scratch that last post, i got it arse up
If there brown it's normal, If there white it's running hot.
Oh fuk it ! look in the haynes book

[Jem]

Scratch that last post, i got it arse up
If there brown it's normal, If there white it's running hot.
Oh fuk it ! look in the haynes book

After messing about with many a turbo charged engine, I can spot a happy spark plug (and plugs that have melted ) The plugs on the E30 are perfect.

[Jem]

I've just had a look at the AFM on my mums 316i M40, and it's exactly the same as the AFM on my car, i.e. Brass flat head screw.

I just home the garage can sort the CO tomorrow to get it through the MOT.

[gareth]

that's high CO reading!

may be wroth whipping theAFM off and giving it a good clean out with some carb cleaner and make sure the flap moves. this is a common fault with 205 gti's and they have a very similar bosch AFM. also the track on the board can get worn but you can salage some more life by popping the lid off, cleaning them and rubbing the tracks with a graphite pencil.

or get another AFM!

[Jem]

All sorted now The MOT tast station sorted the idle mixture, so theres nothing wrong with the AFM The reading before were:

CO% = 5.165
HCppm = 283

The are now:

CO% = 1.529
HCppm = 173

So the CO is now just about spot on, and the Hydrocarbons are also 30% lower

Thanks for all the help guys

[gareth]