95_4X4Runner

Hello all. About six weeks ago I installed a used FIPK from a board member, NCSU-4runner, who's swapping to a 7M-GTE.

Since he didn't need the old AFM anymore, he sent it to me with the air filter already attached. So, I installed it using his AFM.

Prior to the install, I was consistently getting 18.1 MPG mixed city/highway driving back and forth to work. (with adjustment for 10% larger tires than stock)

After the FIPK install, my MPG dropped to 16.3, and I noticed more soot than usual my exhaust tip.

So, I remembered an old Toyota trick. To richen the fuel mixture, you can loosen the spring tension on the flap in the AFM, and to lean it out, tighten the spring tension. I simply cut the silicone RTV around the cover on top of the AFM, and tightened the spring tension a couple clicks clockwise. (first, mark the stock location on the AFM body and gear) After two tanks, it went up to 16.7, then a couple more, 17.6, then after 8 teeth total, I'm up to 18.7 MPG average after two tanks.


The locking tab is at the 8 o'clock position while standing by the drivers side front wheel. To do the adjustment, I used a skinny standard screwdriver, and pushed the tab that holds the gear in place, and turned the gear clockwise. In between adjustments, I just pushed it back on, and when I'm done tinkering with it, I'll reseal the lid. Be sure to keep the area dry while you're tinkering, so the electronics dont' get wet. I would also recommend being careful when adjusting to not let the spring tension go all the way loose...could be hard to get back to stock, which is why it's important to mark it first.

So, here's a
pic (147K) of the AFM with the lid off, and you can barely see the black mark on the body and gear (the black mark is just to the left of the wire).

Mod at your own risk...

Memphis4X4

Nice mod. Do you see any drop in performance?

Your advice to mod at one's own risk is good, seeing that opening up the AFM and having the spring jump out is one thing that I have read about several times here on yotatech.

David

95_4X4Runner

Thanks, nope, haven't noticed a drop. In fact a little ricer was trying to pass me on the way to work Sunday AM, and he couldn't gain on me or pass, I gave up at 70 (in a 55) and let him go by, besides the aerodynamics would've killed me much higher than that.

I've pulled a few AFM covers, and never heard of a spring shooting out, guess I'll have to do a search...

KevyWevy

wow. im really interested in this mod, but im not really likeing the idea of playing with the AFM or MAFM or whatever it is called. i would love to get more than my 15mpg mixed city and highway that i get right now. if you could do little bit of a write up that would be cool. since i've never opened the AMF i can't visualize what you did.

Highland Runner

I did this to my old Supra. Make sure you use that O2 sensor safe sealer when you put it back together.

934rnr

I talked to some mechanics at toyota that tune thier toyota trucks they warned me not to screw with the AFM too much if you lean it out too much you can get detonation which could be disaterous for your pistons. Also you can drill out the little capped area and get adjustment of the afm plate to fine tune your idle as well.