AFM Loose Arm

[chaseincats]

Question for you - my friend's AFM's arm is loose in that you can wiggle it back and forth about a millimeter or two.  Tuning the car with an AFM is obviously impossible since the resistor arm isn't getting consistent results.

I'm guessing there's a bushing in there somewhere that went bad.  Can these be opened up, and if so, are the bushings available?

[Yarb]

Best bet is to find a used replacement that has not been opened up and messed with. Talking about the plastic cover with original silicone in place.

[Zed Head]

I don't think the AFM would even work if the contact arm is losing contact.  Are you sure you're not watching the weight move?  It might have play.  The vane would probably bind if it was loose on the shaft.  A picture or video might help the cause.

I see rivets.  Here's some links.  

http://www.atlanticz.ca/zclub/techtips/afm/index.html

http://www.atlanticz.ca/zclub/techtips/afm/sizeupgrade/index.html

[siteunseen]

I saw this about a loose locking screw? It's on ZedHead's first atlanticz link, about halfway down.

[chaseincats]

5 minutes ago, Zed Head said:

I don't think the AFM would even work if the contact arm is losing contact.  Are you sure you're not watching the weight move?  It might have play.  The vane would probably bind if it was loose on the shaft.  A picture or video might help the cause.

I see rivets.  Here's some links.  

http://www.atlanticz.ca/zclub/techtips/afm/index.html

http://www.atlanticz.ca/zclub/techtips/afm/sizeupgrade/index.html

Sorry, I meant the entire arm assembly as a unit (arm, weight, flap - that entire assembly has some forward/back (open/close of the flap) play.

[Zed Head]

The vane should be binding up in the housing then.  From the pictures it looks they stake the ends of the shaft.  Doesn't look like it's meant to be disassembled.  You'd have to wing it and get creative.  Basically, it sounds trashed otherwise.

[Zed Head]

It's worth big money as a core though.  Don't throw it away or smash it up.

 

 

[chaseincats]

1 hour ago, Zed Head said:

It's worth big money as a core though.  Don't throw it away or smash it up.

 

 

Any place specifically you know that would buy it?  Beats sitting in my garage collecting dust.

[Zed Head]

1 hour ago, chaseincats said:

Sorry, I meant the entire arm assembly as a unit (arm, weight, flap - that entire assembly has some forward/back (open/close of the flap) play.

Actually, not sure how this translates to losing contact with the wiper.  Not really sure what the problem is.

Posting anyway even though there's a reply...

[Zed Head]

2 hours ago, chaseincats said:

Question for you - my friend's AFM's arm is loose in that you can wiggle it back and forth about a millimeter or two.  Tuning the car with an AFM is obviously impossible since the resistor arm isn't getting consistent results.

Might be that there's a problem and you're assuming that it's caused by some wiggle you see in a part.  Probably better off to describe the actual problem and see where other people end up as far as the cause.

And, p.s., these EFI systems aren't really "tunable".  So, not sure what you guys are trying to do .  Good luck.

Edited July 23, 2022 by Zed Head

[chaseincats]

3 minutes ago, Zed Head said:

Actually, not sure how this translates to losing contact with the wiper.  Not really sure what the problem is.

Posting anyway even though there's a reply...

Sorry if I'm not explaining this properly.  If you open your afm cover you will see an assembly that turns right to left.  The wiper arm is connected to a counter weight that is mounted to a pipe that goes laterally through the housing to which the flap inside the afm is connected.  There is play in that entire assembly regardless of how tight you crank the black gear controlling the tension spring.  I'm assuming inside the unit (on the side opposite the circuit board (toward the radiator) there is a bushing on which the rod pivots which is probably dead.

I'm asking if there is a way to access and replace that bushing.

I hope that makes more sense!

[chaseincats]

5 minutes ago, Zed Head said:

Might be that there's a problem and you're assuming that it's caused by some wiggle you see in a part.  Probably better off to describe the actual problem and see where other people end up as far as the cause.

And, p.s., these EFI systems aren't really "tunable".  So, not sure what you guys are trying to do .  Good luck.

I plugged in a different AFM without play in the arm and the problem went away.  I was able to see the richness/leanness change due to the play in the swing assembly on my air fuel gauge.

You can tune the car using an air fuel gauge by changing the tension in the AFM's spring after confirming your water temperature sensor is working properly.  There was a thread on here with a very long adventure learning how to tune my car with that method.