Do you really need an EFI Controller? - Harley Forum

#1 01-31-2009, 03:38 PM

Good afternoon,

I live in beautiful Key West, Florida, and have an '07 Fatboy. I recently installed an Arlin Ness Big Sucker and BUB Jug Huggers Exhaust. I'm waiting on a RiddMaxx EFI controller as it's back ordered. I couldn't wait and took the bike for a spin and it ran great. I then took it for a longer ride up the Keys, opened it up, and the bike ran great again, with a very slight popping or back firing when decellerating. Rode bike around town and the temperature never went above 225 and it still ran great. I checked the plugs and they still look fine. I plan to install the RiddMaxx when I receive it, to see if the bike runs any differently, but it just makes me wonder if I really need the EFI Controller???

Fenderplayer · #2 01-31-2009, 08:26 PM

Rarely do you not need to remap your EFI when you upgrade your intake & exhaust. Stock engines run lean usually, and more airflow tends to make it run leaner. You can cause damage to the engine if you run too lean. If you think you don't need to remap- I'll be surprised if you don't, you should get to a tuner or a dealer and at least measure the AFR.

Likemlouder · #3 02-05-2009, 12:36 PM

Quote:

Originally Posted by Fenderplayer

Rarely do you not need to remap your EFI when you upgrade your intake & exhaust. Stock engines run lean usually, and more airflow tends to make it run leaner. You can cause damage to the engine if you run too lean. If you think you don't need to remap- I'll be surprised if you don't, you should get to a tuner or a dealer and at least measure the AFR.

YES
just because it is running does not mean it is ok. lean conditions will kill your bike in the end. all the new bikes are as lean as they can safely run from the factory (EPA) install the tuner with a proper map and you will see a significant diffrence in performance. and your engine will live to tell the story

#4 03-10-2009, 03:04 PM

I just put Rinehart true duals on my 06 Ultra. I previously had the HDdealer install a Stage 1 kit and do the download. My mechanic tells me with the stage 1 download I don't need a controller. It seems to be running great, but it's not hot here yet. Am I getting the true story??

rjrivero · #5 03-10-2009, 06:04 PM

The closed loop EFI's can and do make some compensations for AFR. The ECM does create a table to compensate fuel delivery. However, this seems to be a small calibration factor, and I can't get any confirmation from Dephi or Harley Davidson to confirm HOW much it can compensate for exactly.

If the readings from the o2 sensors falls outside of that nebulous range, then it reverts back to the stored MAP for the fuel delivery setting.

So can you run a bike with a performance filter and aftermarket pipes without fuel management changes? I suppose you could, but I don't reccommend it. Why?

The EFI is progarmmed lean from the factory. It has to meet epa standards. Even if the bike will auto tune completely, it will only tune to those rediculously lean AFR's and you end up with a hot running bike, that I find uncomfortable to ride.

Second, you can get better manners through the entire RPM range if you go with an aftermarket EFI device and a custom tune.

Third, you get better performance with a custom tuned EFI. No doubt about it. Even a factory stock bike can get performance gains with just an EFI device.

cntrhub · #6 04-27-2009, 10:17 AM

You are a crank sensor that knows the rpm you are moving at. The TPS knows what position the throttle is open at. Both sensors are locked in as if you never touched the air cleaner element.

Take the A/C for example. If I blip the throttle quick when stock, did not that blip just happen to blast to a fast, quick, smooth run up on the rpm? OK, so now here is an air cleaner that moved the rpm up 15/25 rpm as if I raised the throttle plate a little is the idle was low.

Do I need a piggy if I blip the throttle? OK, so now I blip the throttle real quick in stock trim. Will I do damage to the bike if I just keep revving it but the temp never changes or overheats.

You need to ask yourself if the blip acts the freer flowing A/C element and did that too need a piggy for a faster event that happened; like blip-ing the stock throttle quick.

If that confuses you, it is time to read a physics book again. It is not rocket science as you will soon find out how much you do not need the piggy and this lean factor fallacy when the crank and throttle position sensor knew how much fuel to throw in the blip. Did the vacuum suck on a sensor wafer send the correct value?

I think so. I think all 3 did their thing. Watt say ye? Do we need a piggy now that that bike you couldn't wait to ride, just about ride into the sunset trouble free? I bet it will die 200,000 miles later for maybe an oil leak or just freshen up the pump.

You have yet to hurt the bike. Engine damage is "Instant" like lean is a holed 2-Stroke piston is you could call that a lean condition. But an air cleaner pleat?

Makes you wonder...

Gas Man · #7 06-15-2009, 01:19 AM

Plus with a properly tuned bike the motor will run cooler from not being so lean.