Accelerator Pump Feature
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Road Master
Joined: Nov 2007
Posts: 1,021
Likes: 12
From: Greene County, MS
Accelerator Pump Feature
I am getting ready to install my PCIII and I had a question....I was reading about the accelerator pump feature that can be enabled. How many people here use that function and what settings are you using with it? I'm not sure if I should enable it or not.
Road Master
Joined: Feb 2008
Posts: 1,214
Likes: 0
From: Tacoma, WA
I ran it for a awhile and thought it worked well, but when I turned it off I did not notice anything but my milage getting better. I have heard if you do some motor work it is a good feature to have if not it is just wasting fuel.
Elite HDF Member
Joined: Sep 2008
Posts: 4,440
Likes: 148
From: Northwest
Sounds like they are trying to emulate the extra shot of fuel that carburators give when opening the throttle. That need is really only necessary on the carbs, here's why:
The carb uses the vacuum created by the pistons to flow air through the venturi, which caused a low pressure area, which draws the fuel out of the bowl. When you open the throttle, you drop the vacuum for a moment and lose that fuel draw. The accelerator pump makes up for that lost fuel, by giving the engine enough fuel till the rpms catch up and re-establish vacuum.
For FI bikes, makes no sense to me to have it on a stock build, but I can see where it might be nice to have on larger cubes, especially with stock injectors.
The carb uses the vacuum created by the pistons to flow air through the venturi, which caused a low pressure area, which draws the fuel out of the bowl. When you open the throttle, you drop the vacuum for a moment and lose that fuel draw. The accelerator pump makes up for that lost fuel, by giving the engine enough fuel till the rpms catch up and re-establish vacuum.
For FI bikes, makes no sense to me to have it on a stock build, but I can see where it might be nice to have on larger cubes, especially with stock injectors.
Outstanding HDF Member
Joined: Apr 2006
Posts: 2,555
Likes: 3
From: Clarksburg, PA
I disagree that it doesn't feel different.
I have it enabled on my bike and it does make a difference.
My brother has his OFF and if you ride them back to back you will notice the quicker acceleration.
Basically, if you wack the throttle wide open, it will rev quicker.
It may be hard to tell if you can't jump from one bike to the other as I don't really notice if I decide to take his bike out for a spin when he's not around.
He does get better mileage than me, but I didn't buy the bike for mileage so i like the benefit.
I used the settings recommended by PC for street riders...would be curious to try a less conservative setting but like the way the bike is now so I'll leave it. Some day, I'll hook his bike up and change the settings for him.
I have it enabled on my bike and it does make a difference.
My brother has his OFF and if you ride them back to back you will notice the quicker acceleration.
Basically, if you wack the throttle wide open, it will rev quicker.
It may be hard to tell if you can't jump from one bike to the other as I don't really notice if I decide to take his bike out for a spin when he's not around.
He does get better mileage than me, but I didn't buy the bike for mileage so i like the benefit.
I used the settings recommended by PC for street riders...would be curious to try a less conservative setting but like the way the bike is now so I'll leave it. Some day, I'll hook his bike up and change the settings for him.
Seasoned HDF Member
Joined: Oct 2006
Posts: 5,977
Likes: 85
From: Nevada
Several tuners including Jamie at Fuelmoto say not to use it. Best for big builds that may require the added fuel at start up and maybe initial throttle.
I could be wrong but the previous poster may just have a better tuned bike or not comparing apples to apples.
I could be wrong but the previous poster may just have a better tuned bike or not comparing apples to apples.
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The Power Commander Acc pump utility works similar to an actual accellerator pump in a carb. This utility allows the user to add (or remove) fuel to tune e mixture to prevent spikes in the AFR when the throttle is opened at different speeds. In PC III this can be configured by RPM, fuel change %, and sensitivity. The PC V has some more expanded parameters. We typically reserve this for larger builds that develop a lean air spike when the throttle is blipped briskly and recommend using this conservatively as it is only effective for several .ms as the throttle is openend. We have a baseline setting we start out with which is 20RPM/15FUEL/50SENS which is a good starting point.
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Jamie Long / Fuel Moto USA
The USA's Leader V-Twin EFI & Performance www.fuelmotousa.com
Contact 920-423-3309
Email jamie@fuelmotousa.com
Jamie Long / Fuel Moto USA
The USA's Leader V-Twin EFI & Performance www.fuelmotousa.com
Contact 920-423-3309
Email jamie@fuelmotousa.com
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Thread Starter
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Road Master
Joined: Nov 2007
Posts: 1,021
Likes: 12
From: Greene County, MS
Jamie, thanks for the response. After reading your post, I think I'll leave it alone for now. My bike is stock with the exception of the PCIII and SE A/C. It doesn't sound like enabling it will do me much good if any.
Cruiser
Joined: Oct 2007
Posts: 213
Likes: 1
From: Southeast New York
Sounds like they are trying to emulate the extra shot of fuel that carburators give when opening the throttle. That need is really only necessary on the carbs, here's why:
The carb uses the vacuum created by the pistons to flow air through the venturi, which caused a low pressure area, which draws the fuel out of the bowl. When you open the throttle, you drop the vacuum for a moment and lose that fuel draw. The accelerator pump makes up for that lost fuel, by giving the engine enough fuel till the rpms catch up and re-establish vacuum.
For FI bikes, makes no sense to me to have it on a stock build, but I can see where it might be nice to have on larger cubes, especially with stock injectors.
The carb uses the vacuum created by the pistons to flow air through the venturi, which caused a low pressure area, which draws the fuel out of the bowl. When you open the throttle, you drop the vacuum for a moment and lose that fuel draw. The accelerator pump makes up for that lost fuel, by giving the engine enough fuel till the rpms catch up and re-establish vacuum.
For FI bikes, makes no sense to me to have it on a stock build, but I can see where it might be nice to have on larger cubes, especially with stock injectors.
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