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FN2 Running rich

M

mofo10

Messages
48
So I had the FN2 for two years now and have been to two MOT's. My problem is the eco test. Normal is 0.2 CO2 emissions on idle and I have 1.6-1.7. The only thing I have changed is the flash (lowered VTEC engaging to 4500 rpm and upped the rpms to 8600) everything else is stock. The only way I was able to pass is to raise the rpms in neutral to 4500-5000 and let go off the throttle (must be several hard hard revs and keeping them for 15-20 seconds) then everthing goes to green (values drop in limits that are good on the MOT). The MOT guy said it must be something MAF sensor. Have been to a local Honda dealer and there are no faults on the MAF sensor and O2 sensor . So anyone having experience with these strange values? I am not "grandpa driving" my car and like to hit VTEC on a daily basis I so I dont think it is clogged up. Could it be the spark plugs that are old and not igniting all the fuel. I am on 57000 miles and I thing the spark plugs haven't been changed. Any advice you can give me :confused:?
 
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Let me ask you about fuel consumption, I get 18.8 mpg or 12.5 l/100 km mainly city driving and open road driving 27.7 mpg or 8.5 l/100 km. But I tend to do spirited driving quite often. If I am running a rich mixture consumption would be up a few liters. Are those fuel consumption values higher then yours?
 
That mpg is really low, even in Manchester's traffic and heavily modified I see 24mpg daily and 30+ open road.

I'd be looking more at the remap or O2 sensor but if Honda had a look I'm not sure. I wouldn't take their word for gospel but I'd also guess they'd've been more than happy to sell you on overpriced O2 sensor to be honest if there was even a hint of failure.
 
I'm guessing you have flashpro and installed the group N map, could you not do a live data run and post it
 
Neither! The flash was made by a guy who flashed many FN2's and CL9 Accords in my country, it is a custom map, no one had any issues. But I had those values even before the reflash so I tend to think this is not the case. He flashed my CL9 before the FN2, no problems at all. I was running rich even before the flash! It is kinda strange only way I can pass is by floring it at idle for 10 sec a few times and voila everything is back to green values.
 
Would a bad O2 sensor or MAF sensor turned the check engine light on or least it would make some error data log?
 
Running rich would probably cause you to fail the emissions on high HC levels and you’d also see the lambda value being below 1.0
CO2 being too high could be from the catalytic converter not being efficient enough. But again, I’d expect to see an engine management light on as the secondary lambda sensor monitors the catalytic converters efficiency.


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I think it is my PCV valve that has bugging me all the time. I have the same noise like in this video https://www.youtube.com/watch?v=WE18Tb9swqk Tried compressing the hose and the cringing sound stops. I have ordered it and will be replacing it soon. I think that is way I have slightly increased fuel consumption and failed MOT eco tests. Like I said I only pass the eco test when I increase the RPM's hold it 10 -15 seconds then every parameter goes to normal. Probably with increased presure with high RPM's the clogged valve opens up and the excessive gases pass through and get burned and thats how I pass MOT.
 
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