Failed TX Emissions: suggestions!
#1
Three Wheelin'
Thread Starter
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Failed emissions on two areas:
Borh are from Low speed results (15 mph) test
HC (PPM):
Standard (max allowed): 152
Tested at 239
CO (%)
Standard (max allowed): 0.86
Tested at 1.24
Engine was warmed up for approx 20-30+ minutes
1989 S4, 5 speed
Will new 02 fix ?
Here are the other readings for low speed:
Nox:
Standard: 1146, tested at 225
Dilution:
Standard: >6.0, tested at 15.14
HIGH SPEED TEST RESULTS:
HC: standard: 148, tested at 148
CO%:
Standard: 0.94, tested at 0.51
Nox
Standard: 1047, tested at 133
Dilution
Standard: >6.0, tested at 14.51
Thoughts?
Borh are from Low speed results (15 mph) test
HC (PPM):
Standard (max allowed): 152
Tested at 239
CO (%)
Standard (max allowed): 0.86
Tested at 1.24
Engine was warmed up for approx 20-30+ minutes
1989 S4, 5 speed
Will new 02 fix ?
Here are the other readings for low speed:
Nox:
Standard: 1146, tested at 225
Dilution:
Standard: >6.0, tested at 15.14
HIGH SPEED TEST RESULTS:
HC: standard: 148, tested at 148
CO%:
Standard: 0.94, tested at 0.51
Nox
Standard: 1047, tested at 133
Dilution
Standard: >6.0, tested at 14.51
Thoughts?
#7
Chronic Tool Dropper
Lifetime Rennlist
Member
Lifetime Rennlist
Member
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Start with the easy stuff, like ignition maintenence that may not be quite up to date. Plugs for sure (easy and inexpensive), inspect caps and rotors, maybe wires if they are more than a lot old. HC reading is from low-speed misfire, but the CO high means there isn't an air leak. NOx reading shows it isn't lean.
Remember that tailpipe readings from after the cat may reflect the way the engine is running, but the readings are soggy'd/muddled up by the catalyst. Valid readings for real diagnosis come from the test ports/pipes in front of the cats.
A new oxy sensor is helpful past 25k miles or so on the old sensor. The sensors start to lose responsiveness as they age, so max benefit shows up in non-steady-state driving. The load during a rolling dyno test is pretty stable. So while a new sensor might help, it's not a miracle cure on a car that's already close on mixture.
Remember that tailpipe readings from after the cat may reflect the way the engine is running, but the readings are soggy'd/muddled up by the catalyst. Valid readings for real diagnosis come from the test ports/pipes in front of the cats.
A new oxy sensor is helpful past 25k miles or so on the old sensor. The sensors start to lose responsiveness as they age, so max benefit shows up in non-steady-state driving. The load during a rolling dyno test is pretty stable. So while a new sensor might help, it's not a miracle cure on a car that's already close on mixture.
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#8
Three Wheelin'
Thread Starter
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Plugs approx one year old
Oil changed approx 500 miles ago
Bought new O2 sensor, will install Wednesday
Calling Roger tomorrow to see if he has Temp II sensor (anyone have the part number?)
Follow up to follow post the above
Oil changed approx 500 miles ago
Bought new O2 sensor, will install Wednesday
Calling Roger tomorrow to see if he has Temp II sensor (anyone have the part number?)
Follow up to follow post the above
#10
Burning Brakes
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Sounds rich, especially at low speed so the O2 sensor is a good first change. The higer speed the exhaust would be hotter so the catalyst may be able to burn off the excess fuel better (may actually indicate the cats are OK). Let us know what the new O2 sensor does to the results.
#11
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Sounds like weak spark and/or bad timing. As long as your ign parts are good and timing is correct, then you can suspect o2 sens. Any car I've ever had to smog got 5-6oz. Acetone with 10 gal. fresh petro....never fails.
#14
Three Wheelin'
Thread Starter
#15
Three Wheelin'
Thread Starter
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Forgot on list above, recently installed from Roger a EIS intake system. New plugs about 15k miles ago along with wires
picking up from Roger today new distributor caps and rotors and Temp II sensor. Going to install them along with new O2 tomorrow. Put in some "Guaranteed to Pass" about 1/2 tank of premium ago. After get all that done will put in, as suggested here in this thread, 5-6oz of acetone or tolulene, get her good and warmed up and try again.
Have fuel pressure gauge on the passenger side fuel rail and FP shows good. Havent seen any fuel leaks anywhere.
picking up from Roger today new distributor caps and rotors and Temp II sensor. Going to install them along with new O2 tomorrow. Put in some "Guaranteed to Pass" about 1/2 tank of premium ago. After get all that done will put in, as suggested here in this thread, 5-6oz of acetone or tolulene, get her good and warmed up and try again.
Have fuel pressure gauge on the passenger side fuel rail and FP shows good. Havent seen any fuel leaks anywhere.