So as y'all know, the 530is were programmed to run rich because of the thermo reactors.
I know some lean out the mixture by adjusting the afm door tension---
Is there any advantage to using a EURO ECU and AFM over this adjustment? Is it worth it?
530i AFM & ECU - US vs. EURO
530i AFM & ECU - US vs. EURO
1977 530ia
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canada karl
- Posts: 1065
- Joined: Tue Jan 06, 2009 3:50 pm
Adjusting the AFM door tension?
This is the first I've heard of the rich running due to the thermal reactors.What is the adjustment technique to get a leaner mixture?
Thx Karl
Thx Karl
1976 530i. BMW 59 Triumph TR3A(rolling resto). 67 Triumph TR4A(salvageable). 86 900S Winter car
Thanks for the responses.
I'm not an expert, but from what I understand there are two mixture adjustments that can be made on the afm. I am just repeating what I've read here:
The first is the "mixture at idle" screw which is located, usually, underneath the AFM. Sometimes it is covered with a plastic cap, sometimes its a flathead and other times an allan key. This only changes the mixture at idle.
The second mixture adjustment is the overall mixture- this will effect mixture at idle, and everywhere else. This procedure I think was never intended by Bosch to have been done- basically, you must pry open {good luck} the black cover that is siliconed to the underneath of the AFM. Then, there is a toothed wheel with a spring in the middle. There is also a piece of metal keeping that sits on one of the teeth- a clip- that keeps it from moving. Basically, you take the clip off and rotate the wheel to add more or less tension to the spring in the wheel. The spring controls the tension for the AFM doorflap. If its set at low tension, the AFM door will open easier, causing a richer mixture. If it takes too much force to open the flap, it will cause a lean mixture.
I suspect the AFM that came with my car may have been adjusted by PO or their mechanic.... the remanned AFM I bought works fine, but only after I adjusted the spring.... otherwise it was stinking like gasoline at idle.
This is link has a good picture:
http://www.gomog.com/articles/AFMadjust.html
As far as dialing in the adjustment, I think you need to install an oxygen sensor to get the readings off of, or a co meter somehow...... I haven't gotten this far.
And I'd make sure everything else is working 100% - no vacuum leaks, FPR problems, etc. before you make any adjustments to the AFM- otherwise you may just be masking a problem.
I'm not an expert, but from what I understand there are two mixture adjustments that can be made on the afm. I am just repeating what I've read here:
The first is the "mixture at idle" screw which is located, usually, underneath the AFM. Sometimes it is covered with a plastic cap, sometimes its a flathead and other times an allan key. This only changes the mixture at idle.
The second mixture adjustment is the overall mixture- this will effect mixture at idle, and everywhere else. This procedure I think was never intended by Bosch to have been done- basically, you must pry open {good luck} the black cover that is siliconed to the underneath of the AFM. Then, there is a toothed wheel with a spring in the middle. There is also a piece of metal keeping that sits on one of the teeth- a clip- that keeps it from moving. Basically, you take the clip off and rotate the wheel to add more or less tension to the spring in the wheel. The spring controls the tension for the AFM doorflap. If its set at low tension, the AFM door will open easier, causing a richer mixture. If it takes too much force to open the flap, it will cause a lean mixture.
I suspect the AFM that came with my car may have been adjusted by PO or their mechanic.... the remanned AFM I bought works fine, but only after I adjusted the spring.... otherwise it was stinking like gasoline at idle.
This is link has a good picture:
http://www.gomog.com/articles/AFMadjust.html
As far as dialing in the adjustment, I think you need to install an oxygen sensor to get the readings off of, or a co meter somehow...... I haven't gotten this far.
And I'd make sure everything else is working 100% - no vacuum leaks, FPR problems, etc. before you make any adjustments to the AFM- otherwise you may just be masking a problem.
1977 530ia
-
canada karl
- Posts: 1065
- Joined: Tue Jan 06, 2009 3:50 pm
CO2 analyzer
So you pretty well need one to do the adjustment?
1976 530i. BMW 59 Triumph TR3A(rolling resto). 67 Triumph TR4A(salvageable). 86 900S Winter car
I think you mean a co meter or oxygen sensor?
I think to get it right, yes you need some sort of guage to test the mixture.
Im no expert- And if Im wrong about any of this, I hope someone else will chime in....
I think you would need to also guage mixture through the RPM range using one of those items to dial it in correctly.
However, at least at idle, you can tell if your air flow meter is way off by trying to adjust the idle mixture screw. On my remanned AFM that was adjusted too rich, the screw made no difference no matter how much I leaned it out- it was always running to rich. On my correct running one, its adjusted so that maybe just one turn back from it being screwed all the way down seems to give me the right mixture.
How do I know? First, if it stinks of fuel then I know something is wrong (too rich).
After that, I learned here thay if I pump the brake at idle a few times, and RPMS rise, Im running rich. If its too lean RPMS will drop with a pump of the brakes. If its just right then pumping the brakes wont make a real difference and RPMs will drop if you pump the brakes a lot.
I will also add that I could be misinformed in my stating that thermoreactor cars are programmed run richer, but Ive read that in a few posts.
I think to get it right, yes you need some sort of guage to test the mixture.
Im no expert- And if Im wrong about any of this, I hope someone else will chime in....
I think you would need to also guage mixture through the RPM range using one of those items to dial it in correctly.
However, at least at idle, you can tell if your air flow meter is way off by trying to adjust the idle mixture screw. On my remanned AFM that was adjusted too rich, the screw made no difference no matter how much I leaned it out- it was always running to rich. On my correct running one, its adjusted so that maybe just one turn back from it being screwed all the way down seems to give me the right mixture.
How do I know? First, if it stinks of fuel then I know something is wrong (too rich).
After that, I learned here thay if I pump the brake at idle a few times, and RPMS rise, Im running rich. If its too lean RPMS will drop with a pump of the brakes. If its just right then pumping the brakes wont make a real difference and RPMs will drop if you pump the brakes a lot.
I will also add that I could be misinformed in my stating that thermoreactor cars are programmed run richer, but Ive read that in a few posts.
1977 530ia
This is interesting, and seems applicable to our AFMs.
Although, I dont recall reading before about the wiper adjustment.
http://www.itinerant-air-cooled.com/vie ... php?t=7761
Since I have a spare, when I get a chance I will mess around and post results.
Although, I dont recall reading before about the wiper adjustment.
http://www.itinerant-air-cooled.com/vie ... php?t=7761
Since I have a spare, when I get a chance I will mess around and post results.
1977 530ia