Air Flow Meter (AFM)

 

No trick, it should turn easily. Beats me....

 

There seems to be some chalky, white residue on mine, kind of like battery corrosion. Maybe that's making it stick?

 

i have a 22re with a 2.25 exhaust, no cat, and a medium flow muffler, i also have a cold air intake, how many clicks do you guys reccomend? and what is the silencer mod?

 

whoops^ sorry guys i guess i know what the silencer mod is, i have the isr mod done too.how many clicks do you think??

 

I wouldn't touch it. What makes you think by having a cold air intake it needs adjustment?

Your going to end up causing more harm than good.

 

ohhh, i failed to mention i have no 02 sensor, so ots running in full rich, that is why i want to mess with it. i dk not want an 02. i know it hurts fuel economy but i dont want one and dont have the money for one. so now how many clicks. haha

 

How many here have adjust there AFM vain spring and actually run a O2 meter?.

Ive done this some time ago and also thought that there was improvment, But its short lived fantacy, The OBD1 ECU is designed to learn and adjust and always try to keep stoich fuel mixture, What ever you do up front of the engine will be re-adjusted from the aft by the O2 sensor.

Thats why OBD2 was such an improvement, You can program and force it leaner at spacific throttle openings.

What tightening the spring will do is lean out the open circuit mode up to WOT.
The possible bad affects are you can increase EGT, Lower WOT RPM or severe leanout during WOT.
The bad affects is if you tighten it to much it will shut off your fuel pump durring decel and idle.

 

If your not going to use the O2 sensor then just go carb, Your fighting a losing battle.

 

Just a note for myself here since my old vafm died. I went from 4 clicks lean to 6. Trucks been at roughly 22 to 24 btdc full exhaust headers back, no cat, isr mod and 93 octane

 

Just installed Autogauge AF meter with bosch sensor on my -90 4runner 3VZE.

Ratio was 14.4 when idling, and touching the gas pedal dropped it to 13.5. When accelerating full throttle meter showed something around 10 - 11.

Two clicks leaner, and now it idles at 15.4. Partial throttle/cruising gives 14.8 and WOT 11.5 - 12.5 depending on revs, drops gradually when speed increases to 14.8. Now it actually works VERY well. Runs better when cruising, response is better and a lot more power at WOT. Mixture was way too rich and MPG was around 11.

Then I noticed something very strange. ECU does not react to O2 signal. Sensor gives 0.7 - 0.8 volts steady when idling/light cruise and ratio does not change. There are no error codes. And when I disconnect O2 sensor ECU gives an error. So it does get the signal. I also measured the voltage from ecu connector with oscilloscope, steady 0.7 volts. Tried to adjust it with resistors a bit to 0.9 volts, no reaction.

ECU broken?? I wonder why the VAFM adjustment changes mixture when idling/partial throttle, O2 sensor should correct it. But it does not. And it seems that it is the same thing with other 4runners??

 

I have a 93 Truck with the 3VZ engine that has LCE headers and exhaust as well as a S&B cold intake. Had to adjust VAFM two notches richer. If at stock position it would putt, putt, putt when slowing down.

Best acceleration was at 2 to 3 notches lean, over 3000RPM. When accelerating in 3rd gear from 1500RPM you felt everytime the computer adjusted fuel and timing. 2,200, 2,600, and the big one at 3,000RPM. From 3K RPM like a bat out of hell, in 1st or 2nd you where up to redline in a flash.

But when slowing down putt, putt, putt, so I adjusted 2 notches rich. Gained in lower RPM torque below 3000RPM and only felt the bump at 3000RPM.

Girlfriends 92 3VZ (235x75R15) was quicker than my 93 (31x10.5R15), but after heads, exhaust and S&B intake the 93 is quicker with it set 2 notches rich or 3 notches lean.

3 notches lean similar acceleration up to 3000RPM, above 3K RPM I would kiss her in the butt or pull away, big difference. 2 notches rich better acceleration below 3K and slightly better above 3K RPM.

Can you get an 02 sensor that will display wideband and still inform ECU.

Hans

 

http://www.autogauge.com.tw/index.ph...d=66&Itemid=97

I have this and it has 0 - 1 VDC and 0 - 5 VDC outputs. Manual says that the 0 - 1V output is narrowband. I am currently using this. My runner is original, only EGR is blocked.

Strange thing is that the ECU does not compensate for 'lean' mixture. But I heard that some other Toyota model might have similar response to O2 signal. So it is not necessarily broken.

After reading factory manual I am really thinking Megasquirt. Injectors in two banks etc.. No wonder this thing has bad MPG.

 

It only uses the O2 in closed loop.So idling or wide open is open loop.

 

So has anyone done long term fuel milage calculations after the AFM adjustment?

 

Hi all,

I have a 95 4runner 3vze that I have been building for a Looooong time.... haha. Anyways the specs are as follows;

- Rebuilt and bored 0.020 3vze
- Rebuilt heads
- LC engineering air intake, headers, Y pipe, no cat and 2.25" custom mandrel bent exhaust
- EGR/PAIR delete

I had the timing at 18BTDC with 2 clicks lean on the AFM. The power was great but it seemed to heat up the engine WAY too much. Had a very strong odor coming from the exhaust and struggled to pull over 4500rpm. I pulled the plugs and found they were frosty white so I adjusted the timing/AFM back to stock and it runs much nicer. Less power but it accelerates smoother. Still struggles to get over 4500rpm and the odor coming from the exhaust is still there but much less. Plugs look much better but Im only getting 300-350km/tank now. Any thoughts on whats going on here ?

thanks

 

Where and how is the adjustment made to the afm?

 

Hate to say it but when you add more air intake than stock, you have to INCREASE fuel, not decrease. Otherwise your A/F ratio will be way off, causing it to run lean all the time, hence the high temps. However, ash-fouled plugs mean you're burning oil. High-temp plugs will look white but not actually have any ash that you can chip or flake off.

18* is pretty excessive, I've never heard of anyone running past 15* long-term. Try advancing timing to 15* (make sure you're not getting pre-detonation, it sounds like a light grinding noise at very light throttle) and richen the fuel by 1-2 clicks. You might find that a bit more desireable.

And CarSick, you can adjust the VAFM by cutting away the sealant and taking the black cover off, revealing a cog that you can turn one way or another. However, if you don't have any reason to do it (modified air intake, over-bored valves) then it's best to leave it alone.

 

Don't feel bad my truck runs out of steam be for red line too. But I think it's mostly stock. Once I get it flowing better I think it will be ok. I am 15 degrees and hard intake pipe. Is all I have done.

 

Thanks Gamefreak, good to know. Ill leave it alone since Im running a pretty much stock 3.0. If I end up eliminating the crossover pipe i might play with it. I think anywhere from 12-15* advance is the safe zone especially if youre running 87...On a side note im doing the isr mod. My plan is to put a 2" plastic plug on the intake hose where it "y" s down to the silencer box(s). Then im going to mount two fittings (7/16 and 3/4 ) on the plug to run the vacuum lines to that were originally routed to the silencer box..about 15 bucks worth of parts. Not doing it with hopes of any performance gains, more so just trying to clean up the engine bay.