New Shooter on the line.

I have been reading the Dyna forum for several weeks now. I intended to
wait until my 2006 FXDWG arrived (Dealer assures me it will be here some
time in March.) But decided to go ahead and join the group. There seems to
be a great deal of discussion about Harley Davidson’s EFI set up. New EPA
Regs reduce the amount of pollutants that motorcycles can produce and by 2009
requires all motorcycles to be California compliant.

Because of this Harleys EFI must operate within very narrow parameters. In order to meet EPA standards O2 sensors have been installed on the 06 Dynas and will move across the entire Harley Davidson line in the following years. Catalytic mufflers are now in use on some Harley models, and will see expanded application.
O2 sensors can be narrowband or wideband and come into play mainly when cruising at a sustained or steady speed. Wide band sensors will allow flexibility in the EFI (Permit the EFI to use other sensor data to manage fuel supply according to demand or when using a fuel map with richer settings.) If the motor requires a somewhat richer mix, the wide band sensor effectively tells the EFI controller "OK I am reading you as running a little rich but you are still within my acceptable wideband area. When the extra fuel is no longer needed move back to the center of the zone to lean the mix just a little."

The narrowband sensor has very limited flexibility and when the band is on the lean end of the scale (like those on HD EFI.) then the O2 sensor is not so forgiving and effectively tells the EFI, "Look! You are out of compliance lean the mixture until I say stop". The EFI then trims the fuel flow until the sensor tells the EFI that it is happy with
the readings which means your engine is running at Harleys lean factory setting again. Even if using the SERT to reprogram the EFI, the O2 sensor is still a narrowband sensor configured to respond to the lean end of the scale. The only reprieve here is if the SERT can spoof the O2 readings to the EFI. In other words make the EFI believe that the O2 sensor is getting a good read and the mix is within the acceptable and narrow limits. This would mean that the O2 sensors have been effectively eliminated since their real time readings would no longer be relevant.

The Power Commander does much the same thing. Power Commander IIIusb eliminates the O2 sensors so that the EFI will not lean the mixture when running at a steady speed down the highway.

You can also check out the EFI/fuel control setup made by Terry Components which uses a wide band O2 sensor and a learning cpu that will tune the EFI to mach any combination of components you want to bolt together, or at least that is what they claim. Check this t

http://www.terrycomp.com

You can also find several good tech articles at “Heavy Duty Cycles"

http://www.heavydutycycles.com


Obviously older Harleys will not need the O2 sensor eliminators. The new 06 Dyna’s certainly will, because none the fuel map reconfigurations out there will override the narrowband O2 sensors demand to lean the mixture when traveling down the highway at a steady cruse speed. Unfortunately you can't just buy a wideband O2 sensor and use it to replace the HD narrowband sensor. So if you want to make changes to your 06 Dyna (ie. intake and exhaust) then it's eliminate the O2 sensors with PCIII usb or use one of the fuel injection management controllers that use a wideband O2 sensor. On the bright side, we may have some of the last of the Harleys that you can still modify fairly easily. Next years models may be even more difficult to deal with.

 

The perfect reason to keep my 2004.

 

Sounds like you know something about EFI operation. I guess if you wanna keep up with the times of electronic fuel delivery, then you need this knowledge to get by, but what a royal pain in the ***.

Give me a carb anyday on a scooter! They are simple, work well and are roadside repairable. You don't need to be a rocket scientist to get your scoot running right.

I know that EFI will be the standard one of these days, but you can't beat a dialed in carb. If I wanted a NEW H-D, I would definitely change it over to a carb, and yes it would do away with your warranty, but make life alot more simple.

But what do I know, I'm old school tried and true!

 

Reply to DGlide04 and Lakebum

Old school is not a bad thing guys old school is usually solid, dependable and repairable. Look at the wwII
jeep. But we are a resuorcefull bunch and nouthing generates inventiveness like a challange or being told
"Hey you cant do that because the EPA won't like it".

 

that is the best that i have heard it put about the fuel injection . thanks for putting it term that most of us can understand.

 

Hi and welcome to the HDForum from New Zealand, enjoy!! [sm=welcomesign.gif]

A very comprehensive post about EFI, well done. It explains a few things and makes me pleased I live somewhere where the EPA standards are not quite as strict.

 

Personally, I don't fear the closed loop EFI, and have no intentions of trying to defeat it. I think it's the greatest thing since sliced bread.

I put an aftermarket Haltech EFI system on my performance car. This thing is great! I love the tuning capabilites. I can "change jets" without even taking the seat belt off.

Looking foreward to working on my new bike. It won't be as capable as the one on my car, but it's something I can work with.

 

The best money I ever spent was to put Edelbrock EFI in my V8 S-10! Drastic increase in driveability and performance. When it came time to buy a Harley, there was no question, it would be fuel injected.

 

Zyklon,

It does not really matter if the bike is running 14.7:1 Air Fuel Ratio or whatever HD has them set at cruising down the highway. If your bike requires more fuel to stay at the 14.7:1 after mods the computer will add more fuel (within the limits it is allowed) to stay at 14.7:1. The O2 sensors do this job very well.

You need control of the air fuel ratios at wide open throttle (or large throttle openings) and at this point the EFI has dropped to open loop and the 02 sensors are doing nothing, unless the HD setup is different to every other set up I have seen.

I am yet to play with the HD EFI but have tinkered with closed loop systems before on cars as well as the power commander on my last sportbike.

cheers
Surly

 

I'm just going to wait a year...maybe two and by then I'm certain the guys on this forum will have the entire lean Dyna fix down to a science. I talked to my dealer's wrench today and he agreed. [sm=signs007.gif]