Re: Re :Intercooler/o2 volts/Injector constant

[Scot Sealander <Sealand@clarityconnect.com>]

nacelp wrote:
 
> Diacom itself has an error in it's reported O2 voltage.

How did you check this?  Do you have any results?  Curious
people want to know.  ;-)

I checked the Buick GN ECM back about '95/'96 or so and posted the 
results there.  With a multi-turn pot and an AA battery the O2
input voltage and DIACOM reported voltage were measured.  DIACOM 
was right on with actual input volts to the ECMs O2 sensor input.

The difference with the Buick lists commonly reported target O2 volts
and DIACOM target O2 volts is in the scan tools the Buick guys use.  
They started out with an incorrectly reporting scan tool and came up 
with the desired 800 or so millivolts during PE.  They then kept the 
error in the other Buick GN specific scan tools that came out.

It is easy to check for the error.  A *stock* Buick GN will send a fixed
500 mV O2 voltage out the ALDL with key on, engine off.  If you do not 
see 500 mV then, you can ratio the reading to 500 mV and get the correct
O2 volts.  To do this check, make sure you are using a stock chip!

For instance, if you get 440 mV key on engine off, then the error is
500/440 or 1.135 times whatever the scan tool reports.  So if the
target is 800 mV, multiply that by 1.135, and you get 909 mV.
Just about the same value other people like to use as a target
for O2 voltage.

I guess the bottom line is, if you tested DIACOM like that, could 
you send me your results?  
 

Thanks, Scot Sealander

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