AFM problem.. Car won't run right after adjust helical spring.

[9rider]

My Z stalled couple times during the week. I took the cap of AFM off, trying to adjust the flap's helical resistance spring. I make it less resistance so it won't cut off the fuel at fuel pump contact point. The car run great and idle great after all adjustment at air by pass screw ( the one factory adjusted ) and idle screw. But now I feel my Z have less power, I drive same route everyday and watch RPM and speed comparing to the road. Such as I will pass this sign at RPM and speed, and will pass the other sign at RPM and speed. Shifting always is the same RPM. Given the same distance as before, the car pass the distance as lower RPM and speed, of course take longer time too.

More, I don't hear the clear roaring from the exhaust, it sounds quieter . The car rev freely without hesitate, though.

Is there a position reset for the helical spring? 

How do I know the flap register the right amount of fuel air mix.?

Thanks guy.

 

[Xnke]

Should have read up on that first...there is NEVER a good reason to adjust that spring and you've probably ruined your AFM.

 

Replace it and the problem will go away.

[9rider]

I will buy another AFM and measure the resistance  of spring at given flap open at varies positions and adjust the old one.

[NewZed]

You could also just put the spring back where it was.  Much cheaper than buying a new one.  Most of the procedures you find on the web recommend marking your starting point.  Which is a good idea for almost everything you modify.

[9rider]

Yeap I was about to mark it when the helical spring spun out. I think most if those spring from same MAF will have the same position. The different in tension, a little , will be adjustable via adjustable air by pass valve. Narrow the air way of by pass valve will increase force on the flap of MAF and the other way around. But adjusting the by pass air also lead to problem that unaccounted air go in engine lead to my engine running weird now.