Running rich on one side
#11
#12
Readings from scanner at idle:
ST FTRM1(%).......24.2
LT FTRM1(%)......-24.2
ST FTRM2(%)......-25.0
LT FTRM2(%)......-24.2
O2S11 (v)...........0.990 (not charging much)
O2S12 (v)...........0.000 (goes up to .005 at 2K rpm)
O2S21 (v)...........0.015
O2S22 (v)...........0.025
So which O2 sensor should I swap out?
ST FTRM1(%).......24.2
LT FTRM1(%)......-24.2
ST FTRM2(%)......-25.0
LT FTRM2(%)......-24.2
O2S11 (v)...........0.990 (not charging much)
O2S12 (v)...........0.000 (goes up to .005 at 2K rpm)
O2S21 (v)...........0.015
O2S22 (v)...........0.025
So which O2 sensor should I swap out?
O2S11, which is Oxygen Sensor Bank 1 sensor #1, is the upstream sensor on the driver side (bank 1 corresponds to cylinder 1) near the transmission cooler lines. If it is stuck near 1V, it's telling the ECU there's plenty of O2, and the ECU is compensating with +24 ST fuel trim on bank 1.
I think both your downstream sensors (O2S12, and O2S22) may be bad also, but from what I understand, this won't affect fuel mixture.
Passenger-side upstream sensor O2S21 (bank 2, sensor #1) near the front driveshaft looks good, but its popular advice to change sensors together. I understand the reasoning behind that advice is two-fold. First, if one sensor failed, another is likely to fail soon. Second, because the sensors typically fail from accumulated contamination, you may get better results starting with two clean sensors instead of one worn and contaminated one. My practical experience is that changing one bad sensor works. It worked for me for quite a while. I eventually changed the other one, but didn't realize any improvement from doing so.
I bought the NTK sensors from Amazon. It's not clear to me why AB and RN don't stock these, or why the parts they do sell are so much more expensive. They don't run their business on big markups and very wide margins on a lot of other parts like this, so it's not clear to me why they only stock a much more expensive part.
Best wishes with the troubleshooting.
Last edited by binvanna; 02-04-2016 at 12:19 AM.
#14
By both I presume you mean both of those which are on the same side (driver side/ passenger side) as opposed to both up/down stream. Correct?
#16
Sound advice from all.
Found I could reach the connector on the upstream unit, it is behind the coil pack and on top of bell housing. Can't seem to fumble around and depress the release tab, etc. Any ideas or pix?
Went to boneyard and snagged another coolant sensor, this one seems to be more accurate, shows the aftermarket 195 stat indeed opens at 195, temp drops to 187, then cycles back up. Since it is still a frigid 40F here I will keep the 195 until the summer temps hit. As it has be said before, the thermostat controls how cold the engine stays, mine seems to do better in summer with a 180F.
As for closed loop, seems like mine goes closed around 60-70F coolant temp, again I don't believe the ECT sensor was out of range enough to matter for fueling. I have had open ones in the past make a high idle, as the scanner reads -40F.
Found I could reach the connector on the upstream unit, it is behind the coil pack and on top of bell housing. Can't seem to fumble around and depress the release tab, etc. Any ideas or pix?
Went to boneyard and snagged another coolant sensor, this one seems to be more accurate, shows the aftermarket 195 stat indeed opens at 195, temp drops to 187, then cycles back up. Since it is still a frigid 40F here I will keep the 195 until the summer temps hit. As it has be said before, the thermostat controls how cold the engine stays, mine seems to do better in summer with a 180F.
As for closed loop, seems like mine goes closed around 60-70F coolant temp, again I don't believe the ECT sensor was out of range enough to matter for fueling. I have had open ones in the past make a high idle, as the scanner reads -40F.
#17
From earlier:
Nothing to add today on your rich in wrong way issue.
Mentioned in previous reply that after reading thread I would also like to check my temp readings against using IR gun. This afternoon found my IR readings below those sent to computer by about 5 F while aiming directly at ECT sensor/manifold. Readings taken from outlet pipe and radiator inlet were 10-15 lower. Assume from this that presently my actual coolant temps may be a few degrees lower than ScanGauge indicates. Good baseline information to have available if cooling system issues crop in my future.
......
temp sensor is reading 15 or more degrees lower than IR sensor used to spot check radiator inlet temp
Mentioned in previous reply that after reading thread I would also like to check my temp readings against using IR gun. This afternoon found my IR readings below those sent to computer by about 5 F while aiming directly at ECT sensor/manifold. Readings taken from outlet pipe and radiator inlet were 10-15 lower. Assume from this that presently my actual coolant temps may be a few degrees lower than ScanGauge indicates. Good baseline information to have available if cooling system issues crop in my future.
......
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elboy0712
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03-16-2010 09:47 AM