Spanky

Ok I have been thinking of doing the "afm mod" I have read that I should be turning it counter clockwise one tooth so that it will run more "rich". I have also searched on this site and read that somone turned it so their truck will run "lean". His reason for doing this was that he said he ran at a higher altitude (around 7000 ft.) Now I live in Salt Lake City, Utah which has an altitude of about 5000 or so feet. Can someone help me as to which I should run? rich or lean? and perhaps how many teeth I should move the gear.

regularguy412

There's not as much 'air' at altitude, so you won't need quite as much fuel. I'd just go one notch leaner and see how it goes. My 3.0 runs a little rich, but I'm OK with that, since I don't want it to run hot and encourage the dreaded HG meltdown. I'm only about 700 ft above sea level here, anyway. I think the humidity, here, displaces about as much oxygen as ya lose at 3,000 ft, anyway. ( At least my body can't seem to get enough of it when I'm workin outdoors)

Mike in AR

phorensic

IMO you should lean it out 2 or 3 clicks. My 3.0 runs pretty rich even leaned out 1 click with extensive intake mods.

Spanky

Is there anyone else here who is driving their ride at a higher altitude (maybe abound 5000 feet) who recommends going rich or lean on the AFM mod?? or is it not worth the hassle, and i should leave it alone?? I do have (minus the header) a totally new exhaust system.... 2.25" pipe (from the header to the tip), magnaflow cat, flowmaster muffler. K&N drop in, and the Air box mod. I was just wondering if this AFM mod will help any with the computer or whatever recognizing the extra air entering and exiting the truck.

kyle_22r

the computer already compensates for altitude, going leaner won't help you at all. going richer on the AFM can help with power a bit, as toyota tuned these trucks for mileage mainly. personally, i wouldn't mess with it.

Spanky

ok, i have had this mod done for about 3 months now and it is 1 notch LEAN
(reason being at the top of this thread)
it seems like the exhaust smell (not rotten egg smell, just an exhaust smell) is getting more rich. really rich actually . . . . PU !!
now if i put it back to the ORIGINAL position to just leave it be, and pretend nothing happened, it will be even more RICH, but if i lean it out more. . . . then what? i have read some bad things on here about running lean!
what should i do?

Bumpin' Yota

if you want it back where it was, move the AFM back to the origional position and then pull the EFI fuse (or the battery +) for a 20 min. The ECU will resort back to origional programming and commence a relearn...

Spanky

even though putting it back to the original positions means going more RICH ??

Bumpin' Yota

being rich is definately better than being lean...honestly dont know whatto tell ya. The only way things could have changed would be either the ECU tuning to run stoich in closed loop, or an injector is leaking or your AFM is malfunctioning...

Might also check that the cat isnt clogged...

tomasp

I was trying to get better fuel economy with AFM mod so started by leaning it by 3 notches. I have noticed the lack of power (well, it was guttless) and the fuel economy was still poor however a bit better than before.
I have also set my ignition at 13* and it started pinging with 91 octane (which is ~86 octane in USA)
Then I played around by changing it back to stock by a single notch at a time. It still pinged and no real difference in fuel economy. Then I got angry and set it at like 3 notches richer. MAN did it go! But exhaust tip was covered with soot after just one day and the fuel economy was very bad However no pinging!
At the moment I am running at 1 notch rich, no pinging (but the current tank is 95 octane = 91 US).
I find that unless you change a LOT then it does tad to the fuel economy. And if you change a LOT then you have to compensate that somewhere else - either use higher octane or you have a S/C
My O2 sensor is lazy and I think replacing it will be the best mod ever. I will probably try leaning AFM by 1 notch once the O2 is replaced. I want to get a balance between an acceptible performance, cheaper gasoline and no pinging.

Bumpin' Yota

how many miles do u have?

tomasp

around 96K (143K kms)

TNRabbit

robcogliani26 : If you are running rich, something else is wrong somewhere. Changing the AFM at this point is only going to mask the original problem.

Spanky

ok, lets say youre right.... what else is gonna make me run rich? i know its not the cat, i just had a new one put on 6 months ago.

taikowaza

Well, concerning the AFM mod for the 4runner, I started off with a bit of a disaster, when I unscrewed the screws leading to the cable and ripped off the circuit board, with accompanying sinking feeling and wallet drain.
I now am the proud owner of a refurbushed NAPA AFM and I also have a nice hilux one from Japan...so even if I screw up again at least I have a backup.
On the other hand, I have heard nightmare stories of the coil springing off and never being able to find the stock location of the teeth again...
even the Downey catalogue advises us to be really careful...
so, those of you who have done this mod, and feel comfortable with it, it would be great to give us an annotated photoguide, of how to do the mod, without messing it up and screwing up this very expensive part!!!
I know that we have to use an exacto knife to cut the silicone around the black plastic top cover, and remove that, and then we will see a coil of sorts (like watch gears?)...with a screw keeping everything in place? and, this screw needs to be removed...but I imagine that we have to hold the coil in place, and mark it? with a crayon? if we let go=disaster? and then, rotate it? and tighten the screw? is there more to it?
photos would be great, with advice, what to expect, do we have to remove the fuse to reset the computer?
thanks to 2nd gen 3vze AFM gurus for your help
T
ps when to do the mod, what to expect and possible problems and benefits

Spanky

there is plenty of talk on how to do this if you would only search

taikowaza

I enjoyed your thread about the AFM mod. You mention in your last post that there is plenty of information about where to find detailed instructions about carrying out this procedure, with advice and instructions, and advise me to search. It would be more helpful if you guided me to a link. I must say that I do indeed use the search button every day, and find it most irritating that people continually shut down discussion and the exchange of ideas by pretending to be superior in that they may have discovered a more obscure thread than others. Rather than shutting down discourse, be part of the solution and process of creating a public space through helping people access information.
As an educator at an institution of higher learning I do not just take the easy way out and tell my students to "search more" when they ask me a question, and make them feel somehow guilty for being curious. I use my skill and knowledge to assist them as they quest after more and more skill and information. So, Rob, in response to your glib post, I say that you should share a little of your knowledge rather than hoarding it in an attempt to boost your impression of yourself. And that goes for everybody with knowledge and information- I am a firm believer in the free exchange of ideas and information and the freedom and responsibility that goes along with it.

tomasp

OK. I have just created a little write-up on AFM mod, have a look here:
http://www.flickr.com/photos/7118909...7594284969847/

Happy to answer any questions.

ovrrdrive

Nice link tomasp. I actually learned a few things.

Here are the pics from my thread where I did the same thing. I think the way I marked the position is a little more precise.

I also used a pair of needle nosed pliers to hold the wheen while I loosened the screw. I think that was a little more secure too.


Btw taikowaza, there really is a wealth of information on this subject available with a search... I usually don't cop out with a "search for it" reply either though, but there really is a ton of info on this forum about it.

Spanky

a "cop out" huh? do you know how many times a day i see people who are too lazy to use the "search" feature? its there for a reason. but instead of taking a minute out of your day to look for something, you would rather waste everyone elses time hoping they will do the work for you.