Hi I have an air flow meter that shows 1200-1600ohms at mid point flap opening. It's supposed to read around 600ohms. How does the computer see this? The computer sees more air flowing in than actual right? This makes the computer cause the injectors to richen up, right.

Also with the same AFM I have been having an O2 sensor which reads around 0.20VDC at idle and 0.45VDC at 2500 rpm's. This means the computer sees the mixture as lean and enrichens fuel also at idle.

Am I looking at this right or is it leaning instead and richening. See what I mean about having a hard time figuring it out?
Thanks for any input.

 

Some good technical info. like that on the web page below:
http://autoshop101.com/autoshop15.html

 

http://autoshop101.com/autoshop15.html[/QUOTE]

I have read a few of the great articles there, maybe I will reread some of them. I am looking for a flow chart for what happens to the fuel and air as it goes through the engine to try to get a handle on it in my mind. For instance, if the Air Flow Meter is sending full open signal at half open then what does it make the computer do richen or lean? The O2 just reads what O2 concentration at a point in time. So when low is it reading too much air or too much fuel in the exhaust? Thanks

 

I think it depends on the operating conditions. As I understand it, in closed loop mode, the ECU mainly goes by the O2 sensor. The TPS and AFM inputs sort of tell the ECU roughly what is going on with the incoming air and the O2 sensor is used to fine tune the mixture to the proper level. When you go to open loop mode (like when you floor it), the ECU goes more by the AFM and TPS readings and richens up the mixture somewhat to keep the engine from pinging. I think it uses what it "learned" about the air flow vs. fuel flow ratios from closed loop mode when it hits open loop mode, to some degree. If the AFM is telling the engine there is more air going in that actual, the ECU may try to add more fuel than is needed and you would run too rich. Probably will hurt fuel economy if you do a lot of full throttle operation. Might be that someone "tweaked" the AFM at some point in the past thinking it would give the engine more performance:
- http://www.4x4wire.com/toyota/minutemods/afm/

 

Thanks for the info 4crawler.