[Gmecm] $58 Baro code

[Bill Shaw]

If you're using a solenoid and building some hardware to do it you could 
do it with an analog mux and 2 sensors,  one for map and one for baro.  
The analog mux would switch pretty quickly.

Bill

Dig wrote:
> Had another what-if kinda idea....
>
> Hook a dual-port boost solenoid up to the MAP, leave one port vented.
> Periodically during the MAP read (maybe once every couple of hundred loops) , latch the last MAP value, flip the solenoid over to vent, and do a read.
>
> Big question is how fast this could all happen, as the solenoids are pretty slow.
>
> Later,
>
> Dig 
>
> ----- Original Message ----
> From: Scot Sealander <ssealander at Stny.rr.com>
> To: gmecm at diy-efi.org
> Sent: Friday, July 27, 2007 9:09:16 AM
> Subject: RE: [Gmecm] $58 Baro code
>
> The baro is reset with the engine not running.
>
> I would not even bother with trying to reset the baro while running using
> the 3 bar sensor.  The method GM used would force you to have to fill in the
> BP reset table with different values with every different engine combination
> it is used on.  And I would bet that it would not be all that accurate.
>
> Just use a 1 bar MAP sensor that is reading the ambient pressure, and read
> baro directly anytime you want.  You will have to check a number of 1 bar
> MAP sensors to get one that reads accurately.  I found that I could get ones
> that read from 95 to 100 kPa at my altitude.  I think that I am at about
> 600-700 feet.  I am not sure that a 2-3 percent difference in baro is going
> to make that much difference in the fueling calculation though.
>
> Scot
>
> -p://www.diy-efi.org/gmecm
>
>
>
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