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Re: disconnecting NTC sensor brings O2 sensor to life Posted by Larry West [Email]  (#1140)  [Profile/Gallery]
(more from Larry West) on Fri, 19 Jun 2009 11:26:25
In Reply to: disconnecting NTC sensor brings O2 sensor to life, blue87, Fri, 19 Jun 2009 10:00:32 Members do not see ads below this line. - Help Keep This Site Online - Signup |
If you're getting a steady 0.73v from the O2 sensor, on a hot engine, that's because the engine is warm, and the ECU is doing all the right things. The "bouncing" is for cold engines warming up.
If you disconnect the NTC sensor, then you've removed one input to the computer. The ECU no longer knows how hot the motor is, and then starts to vary the mixture slightly. This varying mixture is picked up by the O2 sensor, and then the ECU again alters the mixture based on the O2 sensor. But the best scenario is having both hooked up.
A steady reading on the O2 sensor means the ECU has found an "ideal" mixture for the current conditions. If the O2 sensor voltage is wildly fluctuating, that's because the ECU is searching for an ideal mix.
Remember that the "380" setting on the AMM is not a "perfect" setting. That is where you start the adjustments of the AMM mixture. As I seem to recall (it's been quite a while since I dumped my last LH 2.2 car), you set the AMM to 380, then set your idle speed, and then adjust the mixture for the right reading, either with a CO meter up the tailpipe, or from the test connector.
I presume, also, that you have very carefully inspected everything between the AMM and the cylinder head for any air leaks that could be contributing to the lean condition. I know the turbo elbows and the grommets in the inlet manifold are the usual suspects, but there are a lot of things in that path, and it pays to double-check them all.
Good luck!
_______________________________________ Current: 2002 9-5 Aero Kombi Cosmic Blue 2000 9-5 SE sedan, Imola Red 1990 900S Rose Quartz, Auto Past: 1999 9-5 LPT Combi 1999 9-5 LPT sedan 2002 9-5 Arc 1990 900 5-speed 1986 900 turbo Convertible 1991 9000 turbo 1980 99 GLi 1986 900 turbo 1986 900 S 1991 900 turbo 1984 900 turbo 1976 99 GL
, Fri, 19 Jun 2009 12:50:23, Sat, 20 Jun 2009 09:12:41, Fri, 19 Jun 2009 11:26:25 <-- Viewing This Message
, Fri, 19 Jun 2009 11:52:16
, Fri, 19 Jun 2009 14:57:43, Fri, 19 Jun 2009 16:48:52, Fri, 19 Jun 2009 17:01:33, Mon, 22 Jun 2009 08:58:58
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