Closed loop

dougl

dougl

Living Legend
Joined
Sep 11, 2005
Messages
3,203
Location
Reno, NV
Ride
2007 R3 Classic
To get rid of the decel popping, we fatten up the L tables which are used at low throttle positions (TP). In this range of the L tables, the A/F tables go over 14.57 and the ECU goes into closed loop and uses the O2 sensor to make it run smoother at low TP. However, when it's in closed loop, the ECU adapts and adjusts the fuel to give a leaner A/F regardless of the L table changes. So to keep this from happening, we keep it from going into closed loop by unchecking the O2 sensor box in Tuneboy or installing a PCIII O2 sensor bypass.

I've had the PCIII O2 bypass in and out many times and my conclusion is that the bike runs more smoothly at low TP in closed loop with the O2 sensor connected to the ECU. However, you get more decel popping, which I prefer over a tetchy throttle.

Any thoughts on this?
 
I think you can have your cake and eat it, too. Just go into the A/F table and lower the all values at and below 6% TP to 14.45 or so. Then the bike will never go into closed loop mode and will respect the fattening up you did to your L tables.

EDIT:

I re-read your post and now I realize you were saying that you prefer the way the bike runs at low TP in closed loop mode, despite the decel popping. If that's the case, what I said won't help...
 
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You may still need to fine tune how much you are adding to the L tables. If it is "snatchy" at parking lot speeds you are too rich or it could also be a lean surge. You never have done a dyno tune with a PCIII have you?
 
Pig9r said:
You may still need to fine tune how much you are adding to the L tables. If it is "snatchy" at parking lot speeds you are too rich or it could also be a lean surge. You never have done a dyno tune with a PCIII have you?
Click to expand...

To the previous post, we can keep it out of closed loop with the PCIII sensor or unchecking the O2 sensor box in Tuneboy. No need to mess with the A/F table. I think I've done pretty well eliminating popping - the latest attempt using your (Pig9r's) latest L tables. The problem with popping is at zero or very low TP. You can do pretty well with the L tables but then you lose the fine tuning provided by the O2 sensor. I don't think you can static tune it better than the computer can at low TP on the fly. I wouldn't waste the time or money dyno tuning it for zero TP. To my understanding, Dyno tuning with a PCIII doesn't do anything to the L tables - it provides a trim for the F tables. The problem with keeping the O2 sensor hooked up is that the ECU learns, i.e., compensates for the fatter L tables. I don't see why it needs to do that - seems like a desgn flaw. This kind of technology is on all fuel injected cars. Don't hot cars like Beemers have wide band O2 sensors?
 
Pig9r said:
You know Dynojet is looking for a Rocket in Vegas for the PC5. This would be just the excuse.
Click to expand...

Unfortunately, I don't have the time - or the inclination to do one of the most boring 400 mile drives in the country. My dealer is a major Dynojet tuner, mainly for Harleys. However, the Dynojet site says that the PC5 is for 2009 models. Mine is 2005.
 
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