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Electronic Fuel Injection Made Simple: Basics Of H-D EFI

ThunderMax: EFI Tuning as You Ride

By: Rogue, Toph Bocchiaro, Photography by Rogue
Electronic Fuel Injection Made Simple Basics Of H D Efi
13. To release the main wiring harness from the ECM the release button (top arrow) was pressed and the grey locking bar moved to the full rearward position until the bar locked into the rear detent (bottom arrow). Care must be taken to make sure the bar is in the full rearward position to release the connector’s internal latches; then we removed the connector from the ECM.
13. To release the main wiring harness from the ECM the release button (top arrow) was pr

A closed loop system can be remapped as well as using add-on modules to modify air:fuel that work in conjunction with the factory ECM in the same way as open loop; tuning will still be limited by the narrow band O2 sensors.

While adding aftermarket wideband oxygen sensors allows a wider range of air:fuel monitoring, the stock ECM will still need remapping for changes in engine airflow, and for optimal performance require expensive and time consuming dyno tuning. Be extremely careful when choosing a dyno tuning technician; treat the situation like real surgery. Because of the relative complexity of EFI there are many hacks that capitalize on misinformed customers. It’s very easy for a tech with little experience to make your bike run terribly, then sell you more parts to try and “fix” what he messed up. It’s easy to get fooled into the next, best, black box, so do your homework and make sure you have referrals. It can get very expensive when your bike doesn’t run right. If you plan on any engine modifications try and have a plan and do the mods all at once if possible. That way each time one part is changed—pipes, airbox, cams, headwork, big bore kit, etc.—you won’t need to get a dyno tune.

14. The main harness connector was cleaned and the rubber gasket (arrow) checked for damage then coated in dielectric grease. We routed the autotune harness plug up the seat post past the battery towards the ECM holder.
14. The main harness connector was cleaned and the rubber gasket (arrow) checked for dama

Another option that largely avoids dyno tuning is the addition of a new ECM that is easily modified and can handle a wide range of performance upgrades. There are several on the market that after engine modifications can tune the EFI and ignition just by riding the bike. Ranges of tuning after performance modification vary by manufacturer but they all provide more and better control over the fuel and ignition system. They’re not for everyone, but if optimal tune and avoiding a lot of dyno time is your goal there is an option.

One such device is the ThunderMax ECM with integrated AutoTune that works in conjunction with two wideband oxygen sensors. Using either a stock or aftermarket throttle body the closed-loop system automatically adjusts fuel and ignition requirements due to performance upgrades such as pipes, airbox, and cams. ThunderMax can also add this same closed loop operation on your older Magneti-Marelli or Delphi systems. ThunderMax works with either throttle-by-wire or cable-operated throttle bodies.

The ThunderMax wideband, five-wire oxygen sensors thread into bungs located near the exhaust port, and are the same thread size and location as stock narrow band sensors used on ’08 and ’09 exhausts. For ’10-12, smaller oxygen sensors were used and located forward of the catalytic converter near the transmission. The ThunderMax sensors must be mounted in the ’08-09 location and on newer machines either new bungs will need to be added to the existing headers in the upper location (with the lower stock sensors removed and ports capped) or ideally order an exhaust system for a 2009 model (fitment is the same for ’10-12 models) and the ThunderMax sensors will install without modification. ThunderMax has all the info needed and detailed instructions and support.

15. The autotune harness plugged into the ThunderMax (arrow) with the logo facing up and secured with the two screws. Before plugging in the ThunderMax unit we confirmed the gasket was fully seated in the connector, and the locking bar was all the way open. To avoid damage to the ThunderMax it’s important everything slides into place smoothly and that it is all the way in before engaging the locking bar. The ECM fuse got a dab of dielectric grease and plugged back in.
15. The autotune harness plugged into the ThunderMax (arrow) with the logo facing up and

To get a better look at the system and try it we ordered a ThunderMax TBW (PN 309-362) for ’08-12 throttle-by-wire H-D Touring models. The system includes a ThunderMax TBW ECM with integrated autotune module, two wideband oxygen sensors, USB communication cable, TMax tuner software, and ThunderMax TBW quick start guide.

We recently installed a ThunderMax ECM with an autotune module on a 96ci Twin Cam that had only airbox and pipe modifications. The bike ran well beforehand but afterwards the owner said he couldn’t believe it was the same bike. He reported a super-snappy throttle response and a cooler running motor, and while there was no dyno chart (he didn’t need to pay for one) he said the bike had much more seat of the pants torque.

The First Start

After a new module install or interruption of 12-volt power takes place perform the following procedures:
• Turn the ignition switch on and the handlebar switch to run for at least 20 seconds
• Cycle the ignition switch off and on and start the engine
• Let the motorcycle idle on its own for at least 15 seconds
• Turn off the ignition and then restart the motorcycle.

Normal idle speed should be attained depending on engine temperature. The warm-up cycle will have slightly higher idle speed until it reaches operating temperature.

Source
Zippers Performance Products

(410) 579-2828 | Thunder-Max.com

By Rogue, Toph Bocchiaro
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marc99
I just tuned an 01. the o2 sensor system that auto tuned the fuel resulted in the 'right' AFR, but at 2000 to 2500 rpm resulted in 10 to 12 co% readings - which is rich enough to rich misfire. autotuninng can get you 'close' to correct fi settings on a stock cammed bike, but it takes someone to actually 'try' different amounts of fuel to see what the engine actually wants - rather than looking at a single gas (O2) and confidently proclaim that that IS the correct amount of fuel.
I hope that people don't think that anything 'autotuned' is as good as it can be.

'Can' a bike be optimally tuned, using autotuning? Sure.
Just figure out, at each cell, what AFR the engine actually 'wants' and let it autotune all those different values - and when you change cams or pipes or heads, just go through the map again and figure out what AFR the engine wants again and then autotune.
marc99
It seems like:
1. going through the AFR table and determining what AFR the engine wants, based on best power and / or engine smoothness
2. takes a dyno
3. that reads realtime hp and maybe a 4 or 5 gas analyzer (which S&S recommended) to help determine optimal fuel and ignition settings -
4. just to get some optimal AFR table.

Seems that it would easier to just go to a decent dyno that reads hp and engine smoothness and tune the bike and be done with it.Using a dyno that only tunes to an AFR value is just as non-optimal as autotuning to an AFR - so that's not a primo option either.

Most people think that they can just slap on some autotune and get perfect tuning - and if that ever happens, it's by luck, not engineering.

I'm not sure about the rest of the country, but i rarely get stock head / stock cam bikes to tune - AFR tuning is usually horrible affected by the longer cams often used in HD's - leaving the sub 2500 rpm cruise excessively rich, esp at greater throttle opening.
marc99
The motorcycle and auto industry has been bombarded with marketing programs that proclaim that perfect tuning can be attained with a $50 wideband o2 sensor for many years and there's a generation of riders that know nothing else.

But there are those of us that know that tuning, mileage and smoothness can always be improved of 'get it close on most bikes' AFR tuning.

Marc Salvisberg
Factory Pro Tuning
Baggers Magazine