M10 AFM specs and testing, documentation eccentricities

[84driver]

I'm watching WRC and testing/fixing my M10 AFM. Grooves in the carbon track, going to reposition the arm to a fresh part of the track. Using this guide from the944.com: http://the944.com/afm.htm
(Barry Burr's alternate hackier guide here: http://www.normgrills.net/bcg/Inject...anchor41563757)

and this schematic from the BMW manual:
[ATTACH]48291[/ATTACH]

Bentley says I can test the resistance between the arm (7) and positive (9) and it should increase linearly but I read elsewhere (such as the944.com) that a voltage must be applied between positive (9) and ground (5) and the voltage should increase linearly between arm (7) and ground (5) as the flap is opened.

Also the Bentley says the temp sensor spec is ~2200 Ohm resistance at 68F/20C but everyone who measures it (including myself) gets measurements of around ~220 Ohms, off by a factor of 10?

Going to do some more measuring and post results.

EDIT: Other temp test results:

http://www.r3vlimited.com/board/showthread.php?t=63031

how low was yours? mine was reading 200 ohms @ 60 deg

Mine was reading about the same

http://autos.groups.yahoo.com/group/318iE30/message/1369

>Steve,
>
>One more thing: according to my BMW factory shop manual on my M10
>car; the resistance of the air sensor that's located in the air
>intake duct should be 930-970 Ohms at 68 Deg F (20 Deg C).
>Regards,
>
>
>--- In 318iE30@yahoogroups.com, "wbg94583" <wbg94583@s...> wrote:
> > Steve,
> >
> > I own an 84 318i (1.8 litre M-10 engine). I checked the resistance
> > figures of Bentley vs. my Hanyes repair manual: both have identical
> > figures for the intake air temp sensor, 2200 to 2700 Ohms at 68 Deg
> > F.

...
>The resistance increases as I open the flapper, however I am puzzled when it comes to the air temp sensor....My measurements were between
220-240 on 2 separate AFMs. Could this be a typo in the Bentley since they don't specify any air temp measurements on the AFM for the Motronic units?

[84driver]

Update

Ok, I made the adjustment and did more bench testing.

[ATTACH]48347[/ATTACH][ATTACH]48352[/ATTACH]

I applied a 5v voltage between pins 5 (ground) and 9 (positive). Verified that I was getting 5v by using the multimeter to test between 8 (reference) and 5 (ground). My little Radio Shack DC transformer puts out a little more actually, about 5.3v.

Testing between 7 (arm) and 5 (ground) I read 0.5v at flap closed. This raises linearly to 3.4v at flap fully open. The linearity seemed to be smoother after adjusting the arm but that may just be placebo. Neither before or after the arm adjustment have I gotten a linear Ohm reading between 7 and 8 as the Bentley suggests!


Before adjustment: (grooves clearly visible in carbon track)
[ATTACH]48349[/ATTACH]

[84driver]

After adjustment photos

Adjusting:
here is where I got the best leverage to lift the wiper assembly after loosening the 7mm nut
[ATTACH]48353[/ATTACH]


After adjustment:
Wiper arm is bent. Also visible is that I wired the transformer into the inside of the connector for pins 5 and 9 rather than hunt down female spade connectors. If you don't have a transformer, you can probably use a 9v battery as in the944.com guide. I read somewhere that this circuit takes 5v so that's what I tested with.
[ATTACH]48354[/ATTACH]


After adjustment:
Better visibility of the wiper assembly being higher on the shaft.
[ATTACH]48355[/ATTACH]


I would have rather just moved the assembly farther down on the shaft, but there was no more outward room on the carbon track and the wiper assembly was already at the lowest point on the shaft.

Time to put it back on the M10 and see if she purrs a bit nicer!

[84driver]

Success!

The power band below 3500 is much smoother now.

[Holland]

I have to say, this is quite interesting. There is such a lack of write ups for the M10 so I know people will appreciate this.

[84driver]

Good & Tight converted an M10 to E85, reports that each click of the AFM leans out the mixture about .2/.3 :

http://www.e30tech.com/forum/showthread.php?t=107890

Also he's using 17# M50 (Bosch type II) injectors as some of the M20 guys do, which I thought might be a good upgrade but he is the first person I've found doing it with an M10.