mojo4x420

I was doing some testing as per FSM.

My AFM meter tests properly on it's own, but failed one test at the ECU.

ECU Tests
Test | Correct Range | Reading

Vc- E2
- | 6-10 | 7.8V
Vs-E2
Plate Closed | 0.5-2.5 | 2.9V
Plate Opened| 5-10 | 7V
Idling |6-10| 7

The AFM tests

Test | Correct Range | Reading
e2-vs | 20-400 | 67.2
e2-vc | 100-300 | 180
e2-vb | 200-400 | 281

The e1-fc tests passed correctly as did the air temp tests

for e2-vs I wasn't sure about. It's within the proper range, but at about 90% open it's around 950 ohms and then at 95-100% open, it's at about 400 ohms. Anything seem strange about that?

So I passed all the AFM tests, but when looking at the ecu it shows too high a voltage (2.9 instead of 0.5-2.5V).

Should I adjust my AFM tension spring until the ecu reads in the correct range?

MudHippy

The 93 FSM says E2 - Vs resistance should be 20-400 fully closed and 20-1000 fully open.

Also from the 93 FSM. http://personal.utulsa.edu/~nathan-b...33volumeai.pdf
A wave pattern denotes non-linear (high/low) fluctuations. So going from 950-400 fits that pattern.

I wouldn't worry about the 2.9v thing. As long as it's enough, a little more shouldn't hurt IMO.

Adjusting the tension spring wouldn't change any test results. Because it only effects how much air flow it takes to open the measuring plate. Unless your trying to mod it to change fueling, there's really no reason to have to adjust the spring.

thook

Good post, Mudhippy.

toyotasaurus

I did the supra AFM swap last week and had to solder my 22re board in so I tested it after and came up with very similar findings as you. Seemed the readings got higher as the plate moved open and then dropped off towards fully open. I said to myself, what the heck might as well see if it'll run, and fired it up. After adjusting the bypass screw on the AFM it runs like a champ so far!

mojo4x420

ok, thanks, I won't worry about it for now then.

I knew the pattern was supposed to be wave like, but the description is quite vague. I was worried that I was in that range, but the behaviour might be off. I've tried experimenting w/ adjusting my afm at times, but I usually just return it back to it's original location that I marked.

My interest was if others afm changed at roughly the same spot. It seemed strange to me that at it would drop off so sharply with such a small amount of plate change. Going from 950ohms to 400ohms with just the slightest more opening of plate from 95-100%.

I guess since the fuel map is all precalculated, it's hard to determine the afm's expected behaviour without seeing the ecu data.

thook

If you used a digital meter, then it will change abruptly. Seems it's better to use an analog meter when testing the measuring opening. The important thing to note is if the readings ever drop out of range. If that ever happens, you'll likely throw a code while driving.

It may interest you to read this thread...
https://www.yotatech.com/forums/f116...ht=afm+testing