Failed emissions test
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Hi all,
My Civic 2002 with the d16v1 engine failed the MOT in Sweden due to high CO under high rpm (They run it at 2500 rpm)
Lambda value was 0.97
High CO and Low Lambda indicates that the engine is running rich.
Any ideas of why it's running rich and what I can do to fix it?
My Civic 2002 with the d16v1 engine failed the MOT in Sweden due to high CO under high rpm (They run it at 2500 rpm)
Lambda value was 0.97
High CO and Low Lambda indicates that the engine is running rich.
Any ideas of why it's running rich and what I can do to fix it?
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most common cause on mine is O2 sensor (what caused the sensor to go is another story)
#6
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Re: Failed emissions test
Um.....cracked or otherwise leaking exhaust (manifold?) causing inaccurate o2 sensor value?
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The exhaust is just recently replaced since the old cat collapsed.
rear o2 sensor just replaced due to previous CEL.
I haven't owned the car long enough to say if it burns oil or not. But all spark plugs are black and the old o2 sensor was black.
Can it be the front o2 sensor that is malfunctioning? Or can it be that the exhaust is leaking after the manifold, I don't hear anything indicating this though.
rear o2 sensor just replaced due to previous CEL.
I haven't owned the car long enough to say if it burns oil or not. But all spark plugs are black and the old o2 sensor was black.
Can it be the front o2 sensor that is malfunctioning? Or can it be that the exhaust is leaking after the manifold, I don't hear anything indicating this though.
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In addition to the previous I must say that it's producing a LOT of exhaust gases. It must be running really rich but still no CEL.
Anyone who can point me in the right direction?
Anyone who can point me in the right direction?
#9
If you think a good mechanic is expensive, try hiring a bad one
Re: Failed emissions test
The exhaust is just recently replaced since the old cat collapsed.
Can it be the front o2 sensor that is malfunctioning?
Also consider possible mechanical problems such as low compression, low vacuum, cam timing error, valve adjustment out of specification, and more
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The cat was replaced with an aftermarket CAT. I doubt this is the issue since spark plugs all go black.
I haven't tested the compression but I'm planning to do it.
I think it's a long while since the valves were adjusted, can this really be causing the car running rich? Can it be ANY vacuum tube that might be causing this or is there any specific tube I can focus on?
I haven't tested the compression but I'm planning to do it.
I think it's a long while since the valves were adjusted, can this really be causing the car running rich? Can it be ANY vacuum tube that might be causing this or is there any specific tube I can focus on?
#11
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Re: Failed emissions test
Can it be ANY vacuum
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How do I go about troubleshooting that?
I tried plugging the exhaust but wasn't able to hear anything at the manifold.
#13
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Re: Failed emissions test
Reconnect battery, do NOT connect the sensors.
Run the engine, see if it is still running too rich.
If it is still too rich the disconnected sensors are not causing the problem, something else is.
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Disconnect wiring from both oxygen sensors. Disconnect battery and open the doors and boot for 15 minutes, this should hopefully drain capacitors and cause the ECM to dump it's learned adaptive values.
Reconnect battery, do NOT connect the sensors.
Run the engine, see if it is still running too rich.
If it is still too rich the disconnected sensors are not causing the problem, something else is.
Reconnect battery, do NOT connect the sensors.
Run the engine, see if it is still running too rich.
If it is still too rich the disconnected sensors are not causing the problem, something else is.
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i would recommend doing what ezone said - scanner will not drain capacitors.
#16
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Re: Failed emissions test
Check what?
IMO if you already had a scanner connected displaying live data and you couldn't discern a root cause of running too rich before, the same scanner won't help you now either.
With no oxygen sensors input, the computer will stay in open loop, It effectively becomes a "Speed-density, non-feedback EFI" system.
NO fuel trim adaptive correction.
YOU will have to manually figure out if it's still running too rich.
IMO if you already had a scanner connected displaying live data and you couldn't discern a root cause of running too rich before, the same scanner won't help you now either.
With no oxygen sensors input, the computer will stay in open loop, It effectively becomes a "Speed-density, non-feedback EFI" system.
NO fuel trim adaptive correction.
YOU will have to manually figure out if it's still running too rich.
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