I thought it was a variable resistor but it has no adjustment and is caked with some hard plastic gunk.

N236 13 7908...that last 8 could be a B
198600-0010

 

it is the variable resistor.

 

Really. Is the stuff inside some sort of anti-tamper thing from Mazda?

 

Yessum!

 

I molested it. Thanks for the help!

 

sorry to bring up an old thread, but i am trying to figure out exactly what this variable resistor is for. help anyone?
TIA

 

.Molested it? Chatch Man,you are just not right..haha!

 

It allows for the fuel mixture to be adjusted but this applies to only at idle.

 

Its to slightly richen or lean the idle mixture on a S4. Nothing crazy.

 

looks like the mixture adjustment.. for S5 i think so

 

actaully the bias is across the entire signal through out the range
but due to the log form nature of the sender output,, the bias is larger at idle than when its at WOT

its an s4 unit,, s5 do not have any resistance based bias trim
the s5 in-fact has a AIR BYPASS screw on the AFM ,, which effectively does the same thing, pneumatically rather than electronically