On all '96+ models with the rear (post-cat) O2 sensor, it also helps adjust
the STFT and LTFT (Short/Long-Term Fuel Trim). It's primary function is
catalytic converter efficiency, but also works with fuel trim.
- Bernd
-----Original Message-----
From: owner-dakota-truck@bent.twistedbits.net
[mailto:owner-dakota-truck@bent.twistedbits.net] On Behalf Of Michael
Maskalans
Sent: Tuesday, October 26, 2004 2:22 PM
To: dakota-truck@dakota-truck.net
Subject: Re: DML: DTC P0138
On Mon, 25 Oct 2004 22:33:26 -0500, Terrible Tom <SilverEightynine@aol.com>
wrote:
> The original function of the O2 sensor was to monitor the A/F ratio to
keep it at an optimal mixture. Then the manufacts. got the great idea to
stick another O2 sensor after the CAT to monitor how well the CAT is
working. What I am left wondering is - does the post-CAT sensor ONLY
monitor CAT efficency? Or does the ECM pull data from BOTH the up and
downstream sensors to moderate the A/F ratio?
>
I think it's on '01 and newer that the value of the downstream is also taken
into account for fuel curves. bernd mentioned the cutoff year a couple
months ago....
-- Mike Maskalans <http://mike.tepidcola.com/dodge/> '98 Dakota SLT CC, 318/46RE/231, D44/Sterling 10.25, 4.10s, 35s on Humvee rims '84 RamCharger Royale SE, 360/727/208, stock, 3.21s, 32s
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