Miata Mailing List: December 1997, Message #75
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From: 	BBirdwell@swri.edu

Subject: re:OBDII thought 

Date: 	Mon, 1 Dec 1997 14:43:07 +0000



Hi, Will!



>Would it not make more sense to install an amplifier in the signal 

>path with variable gain (< 1) and variable offset - meaning, at idle 

>(max vacuum) the circuit outputs the same value the sensor alone 

>does.  At max boost (both intake and exhaust combo), the circuit 

>outputs a value corresponding to max value when normally aspirated.

  Interesting idea. Would the variable gain and/or offset need to be 

compensated for variations in max boost level? Some run 8-9 psi; others run 12 

psi.

  I still prefer the "active-clamp" circuit because it can be preset before 

shipping but I'm open to new ideas. 

  Is there anyone out there with the service manual for an OBD-II-equipped 

car? If copies of relevant pages (schematics, sensor 

diagnostic/troubleshooting/replacement info, etc.) could be provided to some 

of us here on the list (Will Brown, Paul Turin, Robert Ullrich, Ray Ayala, and 

myself), I think we could whip this problem fairly quickly and cheaply. Then 

we could start looking at the wonderful world of OBD-III...

  Any takers or contributors for the shop manual info?

  Any other volunteers wish to help resolve this problem? I can get access to 

a 96M to get outputs from the air-flow meter and EGR but I need to know where 

to tie into the harness.



Regards,

Barry