what is the O2 sensor minimum operating temp?
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the 'official' value is 350 Celsius, which is 660F.
Heated sensors come into range at about 200C.
Other sites may tell you it is lower, like 575F.
Heated sensors come into range at about 200C.
Other sites may tell you it is lower, like 575F.
Last edited by vader86; Jun 13, 2009 at 05:32 PM.
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You mean closed loop temp?
"Once the Oxygen sensor reaches operating temperature of several hundred degrees, the Manifold Air Temperature (MAT) sensor shows an intake air temperature of more than 140 degrees and the Engine Coolant Temperature (ECT) has reached 160 degrees, the computer will switch to closed loop mode meaning the Oxygen sensor’s output is examined along with the MAT and ECT outputs and the ECM adjusts the injector pulse widths (more “on time” or less “on time”) to constantly strive for a 14.7:1 air/fuel mixture "
Last edited by rodj; Jun 13, 2009 at 08:50 PM.
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You mean closed loop temp?
"Once the Oxygen sensor reaches operating temperature of several hundred degrees, the Manifold Air Temperature (MAT) sensor shows an intake air temperature of more than 140 degrees and the Engine Coolant Temperature (ECT) has reached 160 degrees, the computer will switch to closed loop mode meaning the Oxygen sensor’s output is examined along with the MAT and ECT outputs and the ECM adjusts the injector pulse widths (more “on time” or less “on time”) to constantly strive for a 14.7:1 air/fuel mixture "
"Once the Oxygen sensor reaches operating temperature of several hundred degrees, the Manifold Air Temperature (MAT) sensor shows an intake air temperature of more than 140 degrees and the Engine Coolant Temperature (ECT) has reached 160 degrees, the computer will switch to closed loop mode meaning the Oxygen sensor’s output is examined along with the MAT and ECT outputs and the ECM adjusts the injector pulse widths (more “on time” or less “on time”) to constantly strive for a 14.7:1 air/fuel mixture "
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the O2 sensor has to be up to "it's' operating temp to send the right signal.
The program has a "Closed Loop Enable Temp " at which temp the ECM will go into closed loop IF it is getting the right signal from the O2.
That is why people run a heated O2 because with headers the O2 may not get to operating temp at idle.
The MAT sensor allows the ECM to adjust fueling based on the density of the incoming air ( colder air more dense / more fuel)
In the '89 programming I don't see a setting for MAT in relation to closed loop start.
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The coolant must first reach the set temperature, which varies but can be as low as 150F. Also the timers in the ECM must go off, and there are 3 (varied by engine coolant temp) on an early L98 which do themselves vary by year. The ECM is then waiting for the O2 to have the right variance in voltage output before it drops into closed loop.
