AFM issues and seeking advice

[andrewtf]

As stated, we are seeking some advice on our AFM

We developed a sudden problem in Big Emma today where it would start, struggle for a couple of seconds and wheeze to a halt. This was after running beautifully as Emma’s daily driver for two weeks now, while we finish her up for the road.

After an extended diagnostic period, we discovered the AFM was not working properly. We luckily had the one in Murphy (also running beautifully) for a working comparison. The issue is the silver wiper arm mechanism over rotates past the copper(?) fins all the way back behind all of them, so when we then try to start the engine the wiper crashes into the back side of the long fin on the end. It is supposed to remain on the other side, as we can very surely assess thanks to Murphy.

The wiper mechanism has a stop that seems to have come loose? broken? bent? during a backfire, or from age, or from bad luck. So - where as the wiper arm on Murphy has some sort of physical stop preventing it from over-rotating, Big Emma’s seems to have suddenly….gone away. We know the stop is there, but we cannot see what it is or where it is – it must be under the mechanism. We don’t want to dive in there too totally unprepared.

Lastly, the AFM part number is 200 008 006 which does not seem to match anything remotely close to what it should be. We do have a spare 280 201 002 and 280 200 020 we can swap in – although neither one has been tested as of yet.

Is the AFM toast? Can we fix it?
Advice?

If photos or even a video would help, I could make that happen.

Thanks in advance,
Andrew and Emma
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'75 Riviera - 'BIG EMMA' (Pan American highway trip paused for a make over)
'77 Riviera - Murphy' (being reborn.... slowly)
'63 Austin Healey

[aeromech]

Geez, I have no idea what part number AFM will work for you but I would think it best to go ahead and try your spares. Then report back
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Capable of leaping tall buildings in a single bound

[TomWesty]

Do you have photos of the working and non-working wiper arm mechanics? Maybe a Samba brainstorm session can come up with a way of fixing the wiper arm limit. I’ve spent the last 38 years field repairing some weird stuff in the middle of the night in the middle of nowhere as my main occupation. And then of course there is the Baywindow forum secret weapon - Telford. And this is in no way meant to discount all of the other inventive Baywindow Samba dudes.
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[busdaddy]

Ratwell has a list of interchangeable parts.
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[Wasted youth]

FWIW, Bus Depot used to advertise these being exchange-rebuild items.

[Wildthings]

I think the flapper is just limited in its travel, don't think there is anything else that limits the movement. Maybe something has come loose or been bent by a backfire.

Pictures or videos would help.

[aerosurfer]

PM sent... I would love to come by and take a look for you. I think you are near my parents
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[andrewtf]

Thanks aerosurfer.

PM sent back.

We will post a video later containing both the working and non working AFM so we at least have some documentation of what we are describing.

In the meantime, unless someone wiser than me (not difficult in this forum) tells me its a bad idea, we are going to swap in one of our other AFM's and see if that is a cure.
_________________
'75 Riviera - 'BIG EMMA' (Pan American highway trip paused for a make over)
'77 Riviera - Murphy' (being reborn.... slowly)
'63 Austin Healey

[SGKent]

[Wildthings]

[GoBigEmma]

Haha! We got it!

First of all, thank you for all your great advice guys! I am also now wondering about the part number.....Even after a total rebuild, Big Emma remains full of mysteries!

The solution?!

The AFM range is definitely stopped by the flap beneath the wiper, so the part you can't see until you look into it sideways when uninstalled. That was what was stopping our wiper waaaay too far past its usual mark, in its normal position.

Using our extra AFMs, we tried to find a way to adjust the flap separate from the wiper, because this problem indicated that they had obviously somehow become misaligned.

In the picture, you can see what the AFM looked like while misaligned. This is where it is naturally "stopped" by the air flap beneath the wiper rotor.

Eventually, we realized that was just what the tiny screw (encompassed by the plastic black piece on the pivot of the wiper) is for - the one you are never supposed to touch because it can throw all your adjustments out of whack. Well, they were already out of whack so we adjusted that so the wiper was in the same position as Murphys, approximately and - viola! Runs she does!

We will keep monitoring this problem, just in case it comes back. We think the screw may have come a bit loose and then on a particularly hearty backfire have shot the wiper and flap into misalignment. We tightened that screw down nice and tight

Most of all, we were pretty proud of our ability, with your reassurance, of both diagnosing and solving the problem. I guess all that time with Robbie and Colin has, once again, paid off!

Thanks guys - we really appreciate the support
_________________
1975 Bus "Big Emma", 1.8 FI, Hydraulic lifters
Interrupting our Pan-American Roadtrip for post-flood repairs: http://www.thesamba.com/vw/forum/viewtopic.php?t=657738
Follow the trip on our blog: http://www.gobigemma.com

[Wildthings]

The way I like to adjust the wiper it so that with the vane fully open the wiper is right at the (left) end of the resistance strip. This lets the engine get max fuel under full throttle high rpm conditions when you really need it. I then set the spring so that the mixture is correct for good response at part throttle. This might not pass smog in California though.

[Happyfolk]

I see Colin will be at your place June 24th and he is the best anywhere to fine tune your AFM.
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'79 Westfalia Deluxe Campmobile, 2.0L CA FI, Mexico Beige

[SGKent]

The top photo is yours. The bottom photo is from Mayor Richard Atwell's pages. Those pages are a great source of information on smog, tuning etc. http://www.ratwell.com . Also make sure that the door on your AFM is not bent from a backfire. It looks clean otherwise.

yours:

Mayor Atwell's

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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[Amskeptic]

[GoBigEmma]

[SGKent]

If your picture below is suggestive of the final result, the arm/rod that opens the fuel pump points shows that things are way off. If the photo is a before photo then post a photo of the corrected position.

[GoBigEmma]

[SGKent]

that will work
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[GoBigEmma]

As promised, here is an update with the "final" resting position at warm idle.

Thanks again for all your help guys! Man, sneaky AFM!
_________________
1975 Bus "Big Emma", 1.8 FI, Hydraulic lifters
Interrupting our Pan-American Roadtrip for post-flood repairs: http://www.thesamba.com/vw/forum/viewtopic.php?t=657738
Follow the trip on our blog: http://www.gobigemma.com