stevengood

i heard that you take the black cover off and ajust the spring inside but somebody said it can ruin your engine if you turn it to far, i want to know if thats true and the best way to adjust that spring for best results.

KompressorLOgic

you really dont want to open the AFM and mess with it AT ALL ...



unless you know exactly how the afm works, what the adjustments inside do exactly, and how the ECU thinks/makes fuel calculations based on that sensor readings..





if u did ever try which i really wouldnt recomend!!, you would want a digital multi meter to compair readings before nad after adjusting, and

also a wide band 02 to verifiy that your AF are in the proper range, or damage will result.. lean out= detonation, in short a blown motor!





adjusting the springs inside would be kind of like using a SAFC to adjust the air flow reading to trick the ecu into adding or removing fuel, except it would effect the whole range at once id imagine....



in reality tuning requires persise adjustments at all different rpm levels, so this wouldnt be a very good method.

stevengood

i didnt beleive that would work either but there were people saying you can sqeeze 5-25 hp but it depends on what you do to your motor. also how can you tell if you are running to lean is there any obvious signs my car smokes a little when i start it and then stops but thats from leaky injectors and i still get the pop pop sound when deceleration so i dont think i am running to lean just want to make sure so no detenation.

j9fd3s

if you do open up the afm, MAKE SURE YOU MARK WHERE THE FACTORY PUT IT.



basically the % the afm is open = the amount of fuel the ecu will inject. the more its open the richer it will run. up til the door is 100% open. then it wont get any richer. its best to do this while looking at afm voltage, and possibly o2 voltage, and or a wideband. i think mostly this is done, because on a well modded NA they will run lean at cruise, but the stock map is plenty rich up top, so loosening the door will make it a little richer at cruise, but not affect the top end much. we've tested gsl-se's and the s5 na's and the afms can be 100% open by 4500rpms.



there are other tricks to play with it too, depending on how cheap you are

http://forum.miata.net/vb/showthread.php?t...ht=afm+resistor



i should point out that a super afc is like $100 used, and takes almost no brains to install, and does the same thing with *****....

jarroyo

Check this out to better understand AFM and how to test. I had to do this on my 928.

http://frwilk.com/944dme/afm.htm

bostwick

So what is the cheapest but still most reliable way to yank out the Airpump and stock AFM and install good sensor and controller all in one shot?

RONIN FC

Yea, this works. When my N/A was EFI i had a lean spot at 3800 on partial throttle. I tweaked the AFM this way and ironed it out.



I wouldnt worry too much about blowing an N/A like this. Its just not that sensitive to fuel and timing mistakes.

KompressorLOgic

yeah if its a NA it is really hard to detonate and blow it up....



id prolly try it on a spare AFM if u were really wanting to try it that bad, as you could screw it up and that afm might never work right again...



if i ever get a wide band installed, maybe i will try this on my NA some day, but ive been so busy latly i dont know....

j9fd3s

used haltech/microtech/etc etc....



used e6k's usually run around $500....

Tokyo-RX7

dont even attempt to open up the AFM and adjust it. Before you tune your car you need to invest in a good AF meter and a good O2 sensor. Without this it's like your tuning blind, dont be stupid. In stock form the AFM is set to run a little rich. As far as power the AFM is one of the biggest restrictions. There are ways to delete the AFM, but lets just focus on your AFM as it is now. OK, so get the AF meter and a good O2 sensor, most AF meters come with an aftermarket O2 sensor. Then you can go into changing your AFM settings through a controller. Invest in a Apexi AFC, your choice on what you want.... S-AFC, S-AFC2 , AFC NEO. etc. Once you get the unit installed you can start tuning PROPERLY. Allow your car to warm up before you start changing the fuel points. AF meters are very important so dont skip on a cheap unit. Some come with several features such as EGT and knock sensor. I believe the P500 has all these features. If you have trouble figuring out the AFC, Apex has instructions on their website. Im working on some custom parts for the NA 13b right now, im in the R&D stage right now. I am looking to release these products as soon as i get the most out of them. I will try to keep the forums informed on my progress. Im very busy right now tho, i work 12-13 hour days and have very little time to respond. So sorry if there is any delay. Best way to contact is PM. If you have any interest in anything let me kno what you are looking for. Best of luck with the tuning process. - TK