Sorry I know this question has been asked probably many times but I am still having trouble figuring out what exactly is meant by closed loop in relation to the ECM and 02 sensors. If someone could explain this in lay "man term" it would be much appreciated. Thankyou.

 

Here's my understanding of it. When running under part throttle, for example cruising, the O2 sensor(s) are being monitored and the fuel delivery adjusted accordingly by the computer (ECM). That is called closed loop because the computer is using the O2 signal and responding to it. Open loop on the other hand would happen under full throttle. In this case the computer is ignoring the O2 sensor input. The O2 sensor has a narrow range and would give a poor signal under such rich conditions.

That's all I know and I hope it helps.

 

thanks liltrk

That explanation makes more sense to me than some of the long winded ones I've read previously.

Thanks again

 

So what fuel managment would you recommend ???

I´m running my bike without one.

I know there are a couple out there, but I´m interest in knowingwhat system will work better between the closed loop and the open loop.

 

DTT q WEGO II Autotune.....or.... ThunderMax.....both are closed loop autotuners...both have new ECM's and O2 sensors.....both require a laptop or computer connection to tweak....both do away with the dyno tuner....both adapt to all changes....i run the DTT and love it

 

If your question is directed at me, I am afraid I am not in a position to recommend anything. I have no experience with either. I run the ultimate open loop system...carburetor.

 

Thank you for the information.

 

Liltrik's explanation is a good one. Basically, closed-loop uses the O2 sensors to keep A/F at constant stoich (14.7:1) and works in a narrow range of operation from idle to about 3k RPM's and 50% TP (throttle position). It is primarily used to meet EPA specs. Outside that range you're in open-loop mode (O2 sensors not a factor).

There are two (that I know of) wide-band closed-loop systems available, the T'Max AT and DTT. I'm not familiar with the DTT, but the T'Max has it's limitations. First, it is expensive at about $700. It replaces the ECM and establishes its own closed-loop system, but is not as sophisticated a system as the stock ECM. For one thing it has no knock-sensing capability at all, contrary to stock which has a ion-sensing function. Call Jamie at Fuel Moto for an expert explanation of T'Max limitations. He sells both the T'Max and PCIII.

After using the PCIII for almost 18 months now, tweaking it, and reading what I can about it here and elsewhere--I still think it is the best system for the money available if you have a well-tuned map. Fuel Moto sells PCIII's with maps created on bikes with identical configurations, and most including me get excellent results with them. There is no extra charge for the maps. The PCIII eliminates the O2 sensors using eliminator plugs and runs in open-loop mode at all times. IMO this is no disadvantage, as the map can be changed at any time to balance gas mileage and engine cooling to adapt to your riding style and equipment. Sensors already in place adapt to changing atmospheric conditions. There are 225 areas of A/F and ignition timing for each cylinder that can be changed in increments of 1% for A/F and 1° for ignition advance.

 

I'm running the Cobra FI2000 tuner with outstanding results, big sucker kit stage 1 and Vance & Hines oval true dual exhaust. Before the Cobra install it ran extremely hot with lots of decel popping, the Cobra eliminated the popping and were running lots cooler.

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After having owned a 06 with Powercommander III USB and a 08 with HD Screaming Eagle Pro Super Tuner - I will deffinately recommend the last !!!! NO comparison

The ECM on your bike is propably the most sofisticated ECM in the Motorcycle Industry - not bad when youthink aboutit's been there since 2001

The Race Tuner (or newerPro SuperTuner) just lets you edit the stock settings in the ECM

If your engine is stock, near stock or made from HD Screaming eagle stuff you will find a MAP that suits your bike on the Race Tuner CD. Then you can tweak it from there

You will see that maps enclosed with the Race Tuner for 07+ models widely uses AFR 14,6... AFR is Air Fuel Ratio - meaning 14,6g Oxygen pr. 1g fuel

Whenever you put AFR 14,6 in the AFR table... not 14,5 og 14,7 - but 14,6 then ECM will go into Closed loop mode...The O2 sensors are in a narrow band able to tell if the result actually were AFR 14,6 or a little more or less and adjust acordingly

Actually when AFR is 14,7 you have a stoichiometric combustion - this is the "ideal" and "complete" combustion

Prolem with AFR around 14,6 is that there is not any fuel left in the exaust to help cooling your engine so itwill run hot

Enclosed a pic of a AFR table that are typical for 07+ models in the Pro Super Tuner. You will see AFR 14,6 and lower values.. Lower values means MORE fuel. MAP is "Manifold Absolute Pressure" where 20 is around idle and 100 is full throttle

Race tuner and Pro Super Tuner CAN be tuned on a Dyno - but you will get very far with the encloed maps - and in all cases further than you'll get with the HD offered "Downloads"... and what Powercommander does - eliminating the O2 sensors - why would you want to do that ??? True 14,6 is hot running - but if you enrichen the AFR map at idle and low rpm's you'll avoid the heat...And Closed loop 14,6 is good for economy while crusing

If you want to get the best tune you can thenget the Twin-ScanII+Wego kit from Daytona Sensors... Use it to tune your ECM/Race tuner with. That will make sure that what you see is what you get

Sorry for my language - I'm danish and could use some more english lessons ;-) - Hope you didn't fall asleep while reading

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