Fw: Wide band O2 ????

[jdbubb at ix.netcom.com (Dan Bubb)]

I hope I didn't mislead you during the demo.
The Megasquirt shows the O2 sensor readout and you can connect either a narrow band or wide band O2 output to it.
So, it will display the O2 output (in a very usable format that allows easy tuning) but it can't control a WB-O2 sensor.
The wideband sensor needs a controller (unlike a narrow band which at most needs 12V for an internal heater) to:
1. control the current to it's heater to maintain the sensor temperature in a narrow band despite exhaust heat input (or lack thereof) and
2. vary the current "pumped" into the reference cell to keep the O2 content balanced across the sensor cell in contact with the exhaust.

The Megasquirt needs an O2 sensor for tuning. But, it's still subject to the same limitation of the narrow band sensor. i.e the narrow band isn't an accurate indication of A/F ratio away from stoichiometric. It indicates rich or lean, just not HOW rich or lean (with any accuracy).
So, you can tune 80% of the fuel map with a narrow band cause you want it at stoich anyway. The WOT part of the fuel map needs to be tuned with the narrow band O2 clearly in the rich range (.8-.9v). But, to know what your A/F ratio really is you need a wide band O2.
Clear?
Dan


----- Original Message ----- 
  From: Ron Pieper 
  To: Dan Bubb ; scirocco-l@scirocco.org 
  Sent: Friday, October 24, 2003 12:11 PM
  Subject: Re: Fw: Wide band O2 ????



  --- Dan Bubb <jdbubb@ix.netcom.com> wrote:
  > It's an invaluable tool if you have standalone engine management.
  > If you just have CIS it will impress your friends! ;^)
  > Dan

  Wouldn't MS already give me that capability, provided I have my Palm/Laptop connected?



  =====
  Cheapass Ron
   '81 Scirocco S 16 - "Victor Jr." (2.0L 16V, GL 4-speed w/ Quaife, Megasquirt coming...)

  __________________________________
  Do you Yahoo!?
  The New Yahoo! Shopping - with improved product search
  http://shopping.yahoo.com