Insufficient Switching Oxygen Sensor Question
04-20-2011, 11:36 PM
#41
are you 100 perecent sure you have no exhaust or intake leaks??
with the car cold spray down the entire header, and cylender head with brake clean. let it dry than fire the car up and let it run for 15 minutes are there any black stains of soot under the manifold ports, this indicates and exhaust leak from the header to the cylender head.
also wiht the car idling for about 15- 20 mintues and soft rev hear and there over light colored concrette or cardboard should show little puddles of water with weired black bubbles in them, this indicates an exhaust leak directly above the puddle, look for soot stains on the exhaust connections and the chassis of the car.
to check for intake leaks pull the a/c relay to stop the engine from surging as the a/c kicks in and out, also pull the fan relays or unplug the fans so they don't cut you and so it is easier to hear! You can even remve the drive belt, to further cut down on niose. Just make sure the car is cold, or warm, not hot, and don;t let it over heat, only run it this way for 1-2 minutes. Listen for air leaks, and spray cab cleaner on all the pvc, vacuum hoses intake seals, throttle body seals, and inlet air tube conections after the MAF sensor, oe at a time, and change in enigne sound indicates a vacuum leak there.
also won't hurt to clean the Maf sensor wiht electrical contact cleaner, make sure the cleaner is 100 % evaporated befoe plugging it back in. Never use oiled air filters on these engines clogs up the MAF sensor, cause it to run rich, foul plugs, O2 sensors, and cats!!
Any chance someone ran leaded gas?? that would kill the o2 sensors in hurry!
When was the last time plugs wires were done?? Start wiht basics first than work your way up the top. BTW O2 sensors are considered regualr mantanice, and should be changed every 40,000-50,000 miles for best economy.
what puzzels me is that both O2 sensors went at the sme time! what are the chances!! check that the wires arn't burnt, and that the are clean, the O2 sensors require outside aire from the wires and connector O2 sensor side, this is the reason why you neve slpice wires on the o2 sensor side.. vehicle side only!
with the car cold spray down the entire header, and cylender head with brake clean. let it dry than fire the car up and let it run for 15 minutes are there any black stains of soot under the manifold ports, this indicates and exhaust leak from the header to the cylender head.
also wiht the car idling for about 15- 20 mintues and soft rev hear and there over light colored concrette or cardboard should show little puddles of water with weired black bubbles in them, this indicates an exhaust leak directly above the puddle, look for soot stains on the exhaust connections and the chassis of the car.
to check for intake leaks pull the a/c relay to stop the engine from surging as the a/c kicks in and out, also pull the fan relays or unplug the fans so they don't cut you and so it is easier to hear! You can even remve the drive belt, to further cut down on niose. Just make sure the car is cold, or warm, not hot, and don;t let it over heat, only run it this way for 1-2 minutes. Listen for air leaks, and spray cab cleaner on all the pvc, vacuum hoses intake seals, throttle body seals, and inlet air tube conections after the MAF sensor, oe at a time, and change in enigne sound indicates a vacuum leak there.
also won't hurt to clean the Maf sensor wiht electrical contact cleaner, make sure the cleaner is 100 % evaporated befoe plugging it back in. Never use oiled air filters on these engines clogs up the MAF sensor, cause it to run rich, foul plugs, O2 sensors, and cats!!
Any chance someone ran leaded gas?? that would kill the o2 sensors in hurry!
When was the last time plugs wires were done?? Start wiht basics first than work your way up the top. BTW O2 sensors are considered regualr mantanice, and should be changed every 40,000-50,000 miles for best economy.
what puzzels me is that both O2 sensors went at the sme time! what are the chances!! check that the wires arn't burnt, and that the are clean, the O2 sensors require outside aire from the wires and connector O2 sensor side, this is the reason why you neve slpice wires on the o2 sensor side.. vehicle side only!
http://ww2.justanswer.com/uploads/Bl...153_delphi.pdf
04-21-2011, 07:25 PM
#42
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Hey thanks a lot. Luckily I've had another car to drive and had my car on a timeout until I figure this out. but I'll definitely do some of these tests this weekend and let you know what I find out. The car is pretty much up to date as far as maintenence goes. And I did replace the o2's last season but there is a possibility for those leaks. I didn't think about that so I check for those and check the wiring to the o2s for sure. Again thanks a lot for your help!!!
04-21-2011, 09:02 PM
#43
Hey thanks a lot. Luckily I've had another car to drive and had my car on a timeout until I figure this out. but I'll definitely do some of these tests this weekend and let you know what I find out. The car is pretty much up to date as far as maintenence goes. And I did replace the o2's last season but there is a possibility for those leaks. I didn't think about that so I check for those and check the wiring to the o2s for sure. Again thanks a lot for your help!!!
04-21-2011, 11:09 PM
#44
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I have had O2's run every which way. Lean, rich, and/or jagged with poor occilation. The Proportional fueling is where to fix this. Don't be afraid to use negative numbers. Closed Loop .vs Proportional Base is what I adjusted to get my O2's to occilate richer or leaner. If they are lean at idle, add to the 0, 8, and 16 range depending on how much cam you are running. My G8 setup likes negative numbers since it tends to hold on the rich side with only slight, if any dips to the lean side. Usually motors run lean so changing the values from .0050 to.0100 to values of .0080 to .0150 will get enough fuel in the idle to get rid of the lean condition. After this you can add more or less depending on how the tune reponds.
These tables are not available on some 05 and older VCM's. You may have to change the airflow .vs mode to raise the idle into a higher range proportional range, raising the 4, 10, and 12 values to 12, 18, 22. This will put the idle in the higher proportional fueling areas.
No tunes are exactly the same so most will vary but the same principles will apply.
These tables are not available on some 05 and older VCM's. You may have to change the airflow .vs mode to raise the idle into a higher range proportional range, raising the 4, 10, and 12 values to 12, 18, 22. This will put the idle in the higher proportional fueling areas.
No tunes are exactly the same so most will vary but the same principles will apply.
04-22-2011, 01:53 AM
#45
I have had O2's run every which way. Lean, rich, and/or jagged with poor occilation. The Proportional fueling is where to fix this. Don't be afraid to use negative numbers. Closed Loop .vs Proportional Base is what I adjusted to get my O2's to occilate richer or leaner. If they are lean at idle, add to the 0, 8, and 16 range depending on how much cam you are running. My G8 setup likes negative numbers since it tends to hold on the rich side with only slight, if any dips to the lean side. Usually motors run lean so changing the values from .0050 to.0100 to values of .0080 to .0150 will get enough fuel in the idle to get rid of the lean condition. After this you can add more or less depending on how the tune reponds.
These tables are not available on some 05 and older VCM's. You may have to change the airflow .vs mode to raise the idle into a higher range proportional range, raising the 4, 10, and 12 values to 12, 18, 22. This will put the idle in the higher proportional fueling areas.
No tunes are exactly the same so most will vary but the same principles will apply.
These tables are not available on some 05 and older VCM's. You may have to change the airflow .vs mode to raise the idle into a higher range proportional range, raising the 4, 10, and 12 values to 12, 18, 22. This will put the idle in the higher proportional fueling areas.
No tunes are exactly the same so most will vary but the same principles will apply.
interesting, but I think he has an underlying mechanical problem, that needs to be fixed first, maybe it is exaggerated, but the factory lean conditions, perhaps, installed by the factory for better emissions???
Now not to thread jack here but I have HP tuners and a 4.8L LS series motor, LS2 intake, long tube headers, stock size truck injectors, 90mmm throttle body, cold air intake...sometimes more like a hot air intake!!
The motor is run by a 06 LS2 E40 2006 SSR computer. My LTFT are -2 to -3 % while driving and spike to -10 or more on idle!! Seems idle is pretty lean!! I also see IAT temps of 100 degrees well idling at times, this seems to make it run even leaner around -14 to -15 percent! So you are saying this is normal from the factory??
04-22-2011, 06:54 AM
#46
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Lean idle is a common problem especially when your target idle perameters are stock. The problem is if you are rich or lean, the problem is the same. Headers have so much more volume and idle airflow is so low that the small amount of fuel used for switching isn't enough. Not everyone needs to do this but some do.
