RX-7 VAF question

[MazKid]

I finally got all the parts together to make my VAF/cone air filter intake work properly(and it was still all free), and the car runs good but it seems to lag...

Like, say I'm in 2nd gear at 2K rpm...I step on the gas and hear the intake noise but there's no power for like 1 to 3 seconds and then it gradually(but quickly) builds up and pulls hard.

Now I know everyone that has done this doesn't have this problem but might have had it at one time...how did you fix it? Is it because my VAF is angled down to the cone air filter, could that be adding too much gravity on the flapper door?

The car idles fine and drives fine but the lagging gets annoying. Didn't want to mess with some VAF settings(did turn the big gear to bring my idle to normal) and screw something up.

Thanks!
Ryan

[Gen1GT]

Dude, you need to hit the dyno. VAF output also affects ignition timing, which may be causing that. It's possible that you're running a tad rich. Believe it or not, leaning it out will increase throttle response. If you hit the dyno, fill up on premmium and advance your ignition timing too. For the cost of dyno time, you could walk out with 8-10whp more.......

[MazKid]

Well I've never done any dyno testing, and I really don't want to switch to Premium. I'll look into advancing the timing...it does feel like it's running rich but I thought it was more of a flapper door tension problem. Thanks for the help!

[Gen1GT]

Ok, you don't have to switch to premium, but you should be able to do 14-16° initial advance without pinging. Find a dyno operator that can set the timing for you. With the AFM, it's just a matter of tightening up the spring tension one click at a time between runs. You'll know when you've hit peak power, when the hp goes down again. Then just loosen it back one click.....

[TurboProto]

Try making shure everthing is tight some times that can have some effect. or no vacume leaks

[P-rotege]

I had to lean (I think) mine out a couple clicks on the VAF. RX7's use way more fuel,and air than the BP's do, so the ratio doesn't exactly work straight off the RX. Just take the black cover off and move the large gear a couple clicks at a time until the regain the throttle response. I've had mine for a long time so I can't remember exactly what I did but it works great now. I only have to remove it to pass smog

[MazKid]

Well the problem is that when I first put it on the car, several months ago, my brother thought he knew how to do it better and basically took over the install and when I told him that the VAF needed to be tuned, he moved the black plastic piece inside the VAF instead of the gear.

When I put it on yesterday I moved the gear until it idled good, but I don't know where it started from or where that black piece was in stock form. I'll have to re-read that install how to post...

[Gen1GT]

It's misleading to tune it til it idles and runs smoothly. When I originally installed mine, I adjusted it so that it ran and idled the best. Bad mistake. When I hit the dyno, I was 7whp down from my previous best. We leaned it out(tightened it) so that it barely idled. We then bumped up the idle and did some more tuning. I came out 10whp more than when I came in that day.

Moral of the story? Hit the dyno.....

[MazKid]

Yeah, I understand that because when mine didn't idle worth a damn the first time my car was definately faster(did a huge 2nd gear scratch, like 5 seconds, compared to before the RX-7 vaf when on the same bit of pavement I'd barely chirp the tires.

But yeah I should dyno it. I'll prolly lean it out(turn the wheel clock-wise, right?) tomarrow after work and see how it runs.

[FE3-323]

I have not tuned my RX7 meter yet.... but i have been experiencing similar problems
but not all the time.... generally only after startup. range from 2k-3.5k anything more than 1/4 throttle it chokes.... after driving it for awhile tho i don't have problems? why is that?

[MazKid]

Cold start...car runs richer for the higher idle, and it can create a hesitation since your RX-7 VAF is prolly making it run richer.

I tuned mine tonight a little...just turned it a few clicks clockwise and it feels stonger and the hesitation is gone. Tomarrow I'll retune it with a multimeter to make it as close to correct as possible.

[FE3-323]

problem is..... sometimes it occurs when the engine is warm. thats what worries me.

[D323]

problem is..... sometimes it occurs when the engine is warm. thats what worries me.

pull a spark plug and see if its fouled. Might need some dyno time to lean it out like Josh said.

[Gen1GT]

If you want to check your plugs, do a good full throttle run up to 100, then turn off the engine and roll to a stop. Pull a plug and see how it looks.

[MazKid]

Well this project is officially complete.

My dad tuned it the right way. First off, my dad found my freon leak...that's another story though...

2nd, he pointed out that plug on the VAF...that changes how rich/lean it runs in a different way, but messing with it didn't help it much so it was left as is. Next, we found that when my brother screwed with the meter the first time I put it on the car, he moved the black piece by lostening the hex bolt and turning the assembly bit. This in turn made it so that the fuel pump cut off was not touching. So my dad adjusted that so it touched. Then, using the shop manuel for the voltage of the 2nd terminal in the VAF, he tuned it to match both with the key in the ON position car off and with it running, to the best he could. Ofcourse then changed the idle speed...the throttle response is instant and the car pulls freggin hard especially at high RPM...I did a 3 second 2nd gear scratch on a level surface with both wheels, and I nearly get wheel spin in 1st on avarage pavement, ofcourse that's with my 205/45/16 Proxes FZ4s...I'd prolly get a lot of burnage on my regular 14"s...

So I decided to use MazdaRacer's VAF pic and add arrows to tell you how my dad, a Mazda Master Tech, tuned the VAF properly:

The GREEN arrow is the active voltage to the meter which changes when you move the black center piece. With a voltmeter(black probe on ground, red on that terminal that the green arrow points to), you should attempt to achieve these actual Mazda specs as seen in the Protege shop manual:
3.3 volts with the car running.
3.8 volts with the key in the ON position

You won't be able to get the exact numbers but get as close as possible, then tighten down the hex bolt. You can turn the tightened black piece with the car running, counter clock wise(CCW) is rich, clock wise(CW) is lean, and you can see how it affects the engine.
The best way to tune this is with the engine off key in the ON position. Losten the hex bolt and turn the black piece and watch your volt meter and get it to 3.8V, or as close to it as possible, and tighten the hex bolt. Turn the car on and you should get somewhere near 3.3V. With the engine off the fuel pump cut off contact needs to be touching.

Hope this helps any, and makes any sense...I've been leaning under the hood of my running Protege(with exposed exhaust manifold) in the shop which is hot because it got up to 94*F today, so I'm pretty exhausted.
But atleast my car runs GOOD!