Since you don't have that screw, don't worry about it.

Get yourself an air / fuel gauge... pop open the black plastic cover, loosen the phillips (yes... that's what the + style is called) screw, & adjust the cog to run a lil more rich.... and wa-la! no ifs ands or buts... just do it.

 

My AFM came with my turbo parts car. It's OEM and the Tag says L28.

 

No I Have A Turbo Afm The Bore Thing Was Between A Big Bore Tb And The Stock Afm, They Are The Same, The Turbo One Is Exactly 1/4" Larger Than The Stocker Na, There Is A Screw Under That Aluminum, That Is Just A Very Tightley Inserted Plug, Take A Hammer And A Punch And Give It A Little Whack, The Plug Will Move, I Think I Drilled A Hole To Get It Out, I Turned The Screw But To No Avail. Right Now The Car Is Running Fairly Well With The Stock Afm, Now I Just Have To Make The Turbo Afm Work, Maybee Its The Air Temp Sensor.

 

ok... so I had time to look at the Z today... messed w/ the AFM & had some progress (I'll go into more detail in MY thread, so I'm not jacking Sir Shady's).

I took some pics of my turbo AFM (the one w/ the idle screw is the one w/ the blue silicon connector). AFM w/ idle screw is PART# A31-630 840. AFM w/ no screw: PART# A31-624 600.

 

mines the one on the left.

 

ive been driving with the stock afm for a little while now and its doing much better, i need to get the air fuel guage though. next weekend i gotta do my intake gasket, so while the header is out ill grind the welds off and put in an 82 zx o2 sensor, heck maybee ill throw in an 82 computer and harness. that way the computer reads what the engine is doing.

 

Well mine is PART# A31-630 840 but it doesn't have the screw. And the air outlet is sealed. Which is the opposite of the 840 pictured above.

 

That's really wierd... mine must be an odd ball.

 

Or it could be mine Or maybe it's just a casting change that Nissan made and they just kept slapping the same part numbers on them.