Car Wont enter CLOSED LOOP
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From: Mesa Arizona
Car Wont enter CLOSED LOOP
What are the citeria that must be met for the ECM to enter closed loop? Engine operates about 185-195. O2 sensor reads about .87v anything else??? O2 not hot enough?
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From: Bay Area CA
The FSM says the O2 Sensor will not close the circuit until it heats up to atleast 600F. If this circuit isn't closed, the engine will run in "open Loop" mode. ECM supplies 0.45 V and the O2 sensor has a voltage range from 0.1 V (rich) to ~ 1.1 V.
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From: SE NY
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How do you know the ECM is not going into Closed Loop mode??
The ECM's coolant temp sensor must show >135deg F and the O2 sensor must be hot enough and showing voltage swings between .3Vdc and .8Vdc.
If you have a scan tool and monitor engine parameters you must see periodic swings in the O2 sensor readings. If not, go to the heated sensor.
The ECM's coolant temp sensor must show >135deg F and the O2 sensor must be hot enough and showing voltage swings between .3Vdc and .8Vdc.
If you have a scan tool and monitor engine parameters you must see periodic swings in the O2 sensor readings. If not, go to the heated sensor.
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From: Mesa Arizona
I have scanned it with a laptop and WinALDL and the voltage pretty much just stays at .85-.88 all the time. The engine temp was at full operating temp and still didnt go to closed loop. I picked up a heated O2 sensor today I'll let ya know what I find out!
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The ECM needs:
-a few mintues of time after startup
-coolant temp >135 deg F
-the O2 sensor to oscillate between .3-.8 Vdc
Since you have a scanner I assume the ECM is seeing the correct coolant temp, which leaves the O2 sensor as the problem.
-a few mintues of time after startup
-coolant temp >135 deg F
-the O2 sensor to oscillate between .3-.8 Vdc
Since you have a scanner I assume the ECM is seeing the correct coolant temp, which leaves the O2 sensor as the problem.
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Even an uncoated header should retain enough heat to let the O2 enter closed loop, especially at those engine temps.
I think its just a bad sensor.
I think its just a bad sensor.
but I'd probably double check the connetions before I just ran out and replaced it, they're not expensive and at least in my experience there very easy to change.
Le Mans Master
Joined: Feb 2000
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From: Kempner Texas
If, at 2000 RPM or so, the system goes Closed Loop, you need to go with a heated 02.
Jake
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From: Louisiana
The O2 sensor voltage reading should go all over the place every split second. If the voltage stays in one spot and does not move rapidly, then the sensor is likely bad or the connection/wiring to it. You will probably need a heated sensor with aftermarket headers.
Just another thought.
Just another thought.
Le Mans Master
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From: Kempner Texas
The two white wires are interchangable: one goes to a switched 12 volt source that's only HOT with ignition key in the 'RUN" position. The other white wire goes to a good GROUND. Doesn't matter which white wire goes where.
The black wire splices into the wire which leads to the ECM.
Jake
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