bad o2 sensors=power loss?
This is a discussion on bad o2 sensors=power loss? within the General Help forums, part of the LSx Technical Help Section category; Just to clarify something here and not to take away from what he's saying there;the PCM goes from open to ...
02-17-2006, 07:57 AM #61
Just to clarify something here and not to take away from what he's saying there;the PCM goes from open to closed loop based on O2 sensor temperature only.The PCM goes into "acceleration mode" and uses the other sensors -TP,CT,MAP,MAF, and RPM,to figure out the extra fuel needed. It's true that at WOT the PCM doesn't use the O2 sensors,but it stays in closed loop.Just a point of clarification.I don't know how changing the O2 sensors would affect quarter mile times then either,but these are rather complex computer programs and I don't have access to that info.
05-31-2006, 05:46 PM #62
- Join Date
- May 2006
- 1998 Pontiac Trans Am
How do you bench test the sensors with a high impedance voltmeter? Also if I have a 160 degree thermostat do I need to take that out to stop my O2 sensors from faulting?
05-31-2006, 06:05 PM #63
- Join Date
- Sep 2005
- Pueblo, Colorado
- 1998 Pontiac Trans Am
Use a high impedence DC voltmeter. Clamp the sensor in a
vice, or use a plier or vice-grip to hold it. You will need to use the probes from your multimeter to find which 2 wires are the correct ones. Continue to move the probes to different sets until, when you heat up the O2 sensor, you see the readings changed. Then, set them in place and use a propane torch set to high and the inner blue flame tip to heat the fluted area of the sensor. You should see a DC voltage of at least 0.6 within 20 seconds. If not, most likely cause is open circuit internally or lead fouling. If OK so far, remove from flame. You should see a drop to under 0.1 volt within 4 seconds. If not likely silicone fouled. If still OK, heat for two full minutes and watch for drops in voltage. Sometimes, the internal connections will open up under heat. This is the same a loose wire and is a failure. If the sensor is OK at this point, and will switch from high to low quickly as you move the flame, the sensor is good. Bear in mind that good or bad is relative, with port fuel injection needing faster information than carbureted systems.
ANY O2 sensor that will generate 0.9 volts or more when heated, show 0.1 volts or less within one second of flame removal, AND pass the two minute heat test is good regardless of age. When replacing a sensor, don't miss the opportunity to use the test above on the replacement. This will calibrate your evaluation skills and save you money in the future. There is almost always *no* benefit in replacing an oxygen sensor that will pass the test in the first line of this paragraph.
05-31-2006, 06:40 PM #64Originally Posted by z28rktec
05-31-2006, 06:41 PM #65Originally Posted by YoMommasTA
But, heads/cam/headers cars like mine seem to go through them much quicker.
Something else that'll kill o2 sensors that I haven't read yet in this forum...... exhaust leaks.2002 Trans Am 6sp, SLP lid, Holley filter, Shaner S3 TB, Jet Hot long tubes and cats, FRA, HP tuners, Hotchkis STB and LCAs. TEA stage 1.5 5.3 heads, Comp 220/224 114 +2, UMI Boxed SFCs, Edelbrock PHR. Moser 9" 4.11 gears.
**FOR SALE**: http://www.ls1.com/forums/f38/fs-02-silver-t-heads-cam-headers-9-fl-60478/
06-01-2006, 08:51 PM #66
This is one of the best info filled threads ive seen on here in a long time. Usually i go to ls1tech for these things. Except for the slight bickering it was very nice to hear some technical knowledge
06-02-2006, 04:34 PM #67
You will also notice how it actually occurred 3 months ago. I've noticed that lately this forum has sunk to a new low on technical discussions. Try to have an informed discussion on a subject and you get a pack of howling dogs yelping irrational things about how they don't understand what they are talking about and they don't care. This actually occurred in the last week. Amazing.
Just an observation that you brought to mind.
I brought up this thread in another thread because I remembered it well-it really is informative and helpful. I'm hoping it will bring about a different direction for this forum.
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