O2 Sonsor DTC P0131 & P0151 need help!!!

nupicasso

Hey ladies & gents,

I have an 08 Nightster. It has around 1700 miles on it. Since the day I bought it I've had problems with it running too lean(pinging etc...) and inconsistent. On hotter days it seems to idle higher and run sluggish. when i brought it to the dealership they would say that nothing was wrong with it. I knew better than something wasn't right.

Anyway, after reading about fuel processor and emissions, I decided to get the cobra FI2000r O2 fuel processor. Which has been a Godsend to a degree...It's not running lean anymore, but it still runs inconsistent at times and idles high after running a while. So as i do, I come on these sites and learn alot. I learned how to do a diagnostics test. I did one last night and got the dtc codes P0131 and P0151(which are o2 sensors lean or failure).

Now what I'm wondering, does this have to do with the fuel processor...or is it that they were always like this(without the dealership even bothering to check), which is why the bike has been running inconsistently all along.

note: I also noticed that my air filter needs to be replaced and wondered if this had to do with and or ties in to the o2 sensors having that code or the bike running "extra" inconsistent the past few days.


Hope ya'll can help. Would appreciate it!

glider

The sportsters are a difficult bike to get to run smoothly as compared to the big twins.

The dealers will wash their hands of a bike when it comes to mixture settings because EPA will jump all over them if they tamper with the settings to richen it up and they also can get a big fine for doing it to the tune of $10,000 so most don't risk it.

Not sure about the cobra FI2000r O2 fuel processor if it uses bypasses for the 02 sensors or not, did you unplug the sensors and add a resistor in line when you installed it? Some piggyback units like the cobra eliminate the 02 sensors and others keep them in line.
If not then you may have a problem with the 02 sensors being out of parameters and may need replacement. First find out if they are functioning or bypassed, that may be the reason for the 02 codes you are getting. You could try unplugging the processor and run it without the unit to see if you still get the 02 codes.

As far as the inconsistent running, check the intake with a can of WD40 by spraying it around the seals and see if the idle changes. If it does, you have a leaky intake seal that needs replacement. This will cause inconsistent idle problems.

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nupicasso

Glider,

I did unplug the sensors and plugged the processor in between(so to speak). You think maybe it is just "telling" the sensor that it's lean as to push more gas through??

I also just changed my air filter and it seems to be running a lot better. Getting more airflow...

Thanks for the advice on the intake as well. I was just reading something about that.


"The Dude abides."

glider

What you are saying is that you are running the 02 sensors connected and not bypassed with a resistor on the end of the wire instead of the 02 sensor?

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nupicasso

I'm gonna try my best to explain this...wish me luck...The fuel proccessor has connectors to the fuel injectors and sensors...The processor is basiclly the go between from the electrical to the sensors and injectors. I had to unplug them, plug the processor in....and plug the injector and sensor plugs into the female ends of the processor cords.

glider

OK, so you aren't using resisters to "fool" the processor and you have two male and two female plugs that go inline to the injectors from the unit. On the same page now?

You still have the 2 codes for the 02 sensors?

If you have the codes, there's a possibility that the 02 sensors are bad or not giving the correct readings to the ECM

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nupicasso

Ah... foiled again! I guess I'll be takin her back to the shop for a fixin. Luckily she's under waranty.

Thank you so much for your help.

Happy riding

glider

One other thing comes to mind here. I haven't done much with the cobra unit but check on the map that you used to make sure it is the correct one that is for the 02 sensor bikes.

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wildspirit97

the cobra is a lot like the TFI it has the adjustable "pots". the fi200r piggy backs the injectors and the oxygen sensors and is a closed loop system. Adjusting the pots "LOW, MID or HIGH range only affect the tuner when your not in closed loop. From what I understand the bike is in closed loop most of the time.

glider

You're right, I was thinking of the fuel pac. The closed loop is basically cruise under light load.

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