[Gmecm] Adjusting 7730/$8D for larger cam

[Mike Frels]

When I added a heated O2 sensor I closed the heater circuit via a relay that was switched in conjunction with the PORT circuit of the A.I.R. system. That way the O2 sensor was only powered when the ECM allowing air into the exhaust manifolds for a while after startup.

-----Original Message-----
>From: Robby <roblewis at bigriver.net>
>Sent: Feb 5, 2007 10:58 AM
>To: gmecm at diy-efi.org
>Subject: Re: [Gmecm] Adjusting 7730/$8D for larger cam
>
>A lot of people are powering the heater by the fuel pump circuit, that way
>your heater will only
>be on when the engine is running... helps your O2 live longer
>
>----- Original Message ----- 
>From: "Jay Vessels" <jay at vessels-clan.com>
>To: <gmecm at diy-efi.org>
>Sent: Saturday, February 03, 2007 5:29 PM
>Subject: Re: [Gmecm] Adjusting 7730/$8D for larger cam
>
>
>> Hi there!
>>
>> A heated 3-wire sensor (i.e. AFS-74) looks to the ECM like a single-wire
>> part so no worries there.  You supply switched 12V and ground for the
>> heater.  The signal wire connects to the ECM just like the single-wire
>> one.  The heater is always powered with the ignition key on, so there's no
>> worries about having to control the heater with the ECM.  I powered mine
>> from the same circuit that powers my ignition coil, for instance. The
>> heater isn't polarized, so it doesn't matter which wire is power and which
>> is ground.
>>
>> My local GM dealer had both the sensor and a pigtail harness for the
>> 3-wire plug in stock, so it was a quick, easy addition.
>>
>> Jay Vessels
>> 1982 Chevrolet S-10 Sport, 2.8V6 TBI
>> 1984 Chevrolet S-10 Blazer Sport, 2.8V6 (TBI pending)
>
>
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