Throttle & PC-III

[AZrider]

As has been discussed ad finitum on many sites, modern CARB '08 fuel injected bikes have an abrupt throttle shut off so they can minimize fuel during the ridiculous emmissions test they are required to pass. Hydrocarbon emissions from motorcycles and cow flattulance being the prime movers in global warming. <_<

I'm learning how to finese the throttle on the FJR (as I did my BMW and ST-1300) during shifting and cornering. I've read some of the technical info on this site and others about the PC-III. I was wondering if I could get comments on how this has improved (or not) the "snatchy" throttle response? It's just irritating (and disconcerting) to roll out of a corner, add some throttle and nothing happens until I twist a RCH more and then suddenly, with a jerk the power comes on.

I know about taking up on the throttle cable slack and balancing the fuel. It was commented on my other thread that during deacceleration (throttle closing) that instead of metering down, the CPU controlling the fuel shuts of the fuel flow completely. I agree that this is probably the culprit and that "dry intake" etc is the reason that there is hesitation, i.e. it takes time for the fuel to get down to the cylinders and therefore there is a "lag" of a few milliseconds before the engine sees fuel from my "request for more power" is delivered.

If there were some way to re-program the stock CPU that would be preferable but I think the PC-III is probably the answer although a bit pricy, but what isn' for these machines?

If you have a PC-III could you comment on: 1. The installation time. 2. Did it solve the problem? 3. What program did you download?

I'm not looking for more power, just smoothness.

AZ

 

[HaulinAshe]

I resisted the PC-III on my 05. Instead I opted for the Barbarian Mod. That eliminated MOST of the problematic mixture on the 05.

There was, IMHO, no way the Barbarian Mod was going to eliminate the lean mixture issues on the 07. Unlike the 05, the 07 exhibited clear issues of lean conditions (for me) all the way into the 35% throttle range. So I bit the bullet and bought a PC-III.

Only a week on the PC-III, but I would never go back. I agree that reprogramming the stock ECU would be a first choice. But I'm sure the legalities of allowing that to be done, or sharing the info necessary to modify the program, would be severe liability for Yamaha. IMO it will never happen.

Coming from years and years of tuning carbs, I look at the PC-III as the most expensive jet kit I ever purchased. But it works, plain and simple, it works!

Installation is straight-forward, simple and documented well. I spent some extra time deciding exactly where and how to mount the unit, making sure I had enough wire to mount it where I wanted, rather than exactly as their install pictures indicate. I used thick, double-stick, sponge rubber tape instead of the velcro supplied, but only because of where I chose to mount the box. My goal was to place the PC-III against the right side of the tray so that my air compressor would still fit inside the tray/box. Everything worked out.

I also recommend taking the time to tape over the disconnected O2 sensor plugs and not leave them exposed to the elements. If for some reason the PC-III is compatible with my 2010 FJR, then I'll be hooking up the O2 sensor again.

IMO there are four things necessary to smooth out the 07... simply NECESSARY!

* Eliminate all the throttle cable play. That includes adjusting both sides, the one near the handlebars and the one under the tank near the throttle body.

* G2Ergo throttle tube

* PC-III

* 05 Clutch Slave Cylinder

In that order.

IMO - Relaxing the 3rd throttle spring can be considered "optional" and has more to do with your personal preferences for throttle tension and the grips you have installed.

Jeff Ashe

While I'm editing this thread, I'll take this opportunity to put in a shameless plug for Jeff at SportBikeEffects. He made the PC-III purchase both affordable and easy for me. Thanks Jeff!

 

[AZrider]

I resisted the PC-III on my 05. Instead I opted for the Barbarian Mod. That eliminated MOST of the problematic mixture on the 05.
There was, IMHO, no way the Barbarian Mod was going to eliminate the lean mixture issues on the 07. Unlike the 05, the 07 exhibited clear issues of lean conditions (for me) all the way into the 35% throttle range. So I bit the bullet and bought a PC-III.

Only a week on the PC-III, but I would never go back. I agree that reprogramming the stock ECU would be a first choice. But I'm sure the legalities of allowing that to be done, or sharing the info necessary to modify the program, would be severe liability for Yamaha. IMO it will never happen.

Coming from years and years of tuning carbs, I look at the PC-III as the most expensive jet kit I ever purchased. But it works, plain and simple, it works!

Installation is straight-forward, simple and documented well. I spent some extra time deciding exactly where and how to mount the unit, making sure I had enough wire to mount it where I wanted, rather than exactly as their install pictures indicate. I used thick, double-stick, sponge rubber tape instead of the velcro supplied, but only because of where I chose to mount the box. My goal was to place the PC-III against the right side of the tray so that my air compressor would still fit inside the tray/box. Everything worked out.

I also recommend taking the time to tape over the disconnected O2 sensor plugs and not leave them exposed to the elements. If for some reason the PC-III is compatible with my 2010 FJR, then I'll be hooking up the O2 sensor again.

IMO there are four things necessary to smooth out the 07... simply NECESSARY!

* Eliminate all the throttle cable play. That includes adjusting both sides, the one near the handlebars and the one under the tank near the throttle body.

* G2Ergo throttle tube

* PC-III

* 05 Clutch Slave Cylinder

In that order.

IMO - Relaxing the 3rd throttle spring can be considered "optional" and has more to do with your personal preferences for throttle tension and the grips you have installed.

Jeff Ashe

While I'm editing this thread, I'll take this opportunity to put in a shameless plug for Jeff at SportBikeEffects. He made the PC-III purchase both affordable and easy for me. Thanks Jeff!

Thanks, Jeff. I was re-reading some of the comments on the G2 and thought that maybe I'd start with that mod. Shame that we have to make these "corrections" on a new bike.

AZ

 

[John_Dumke]

Ditto on what Jeff Ashe said.

In stock form if you roll on the throttle the bike doesn't react, because there is not enough fuel.

But with the PCIII when you give even a little throttle the bike reacts. I used the stock map that came with the unit. The bike is a pleasure to ride now. I mounted the unit laying flat between the gas tank and the tool tray. It is a tight fit and requires a small amount of plastic trimming, but it is out of the way and in a spot that would never otherwise be used. Installation was a piece of cake. About 2-3 hours for me, but I like to go really slow and bond with my bike.

I also bought it from Jeff at Sportbikeeffects. Good price and quick shipping.

IMHO, anything less than the PCIII is a band aid, not a fix. (for the snatchy throttle during roll on, and the lean surge at highway speeds).

 

[temp357]

I considered the 2006 FJR borderline unrideable as far as throttle response was concerened...until i put a pciii in. At first I seriously regretted buying the bike, due to the surging and snatchy response.

Do yourself a favor and get a PCIII. With the PCIII the bike is almost a dream bike, with near perfect throttle response. I'm now amazed every time i ride the FJR! What a great bike

 

[sprint_st]

I have the PCIII and it did make the throttle response better, it is NOT a cure. Yesterday I did about 500 miles on some of the curviest roads in the SE. Maintenance throttle is NOT clean, BUT it's OK AND no worse than any other FI bike I rode. Way better than stock. Although the G2 may be the best thing since buckwheat, but I'm not sure it's absolutely necessary, depends on your bike.

You did hit on one thing, PCIII is no way as good as programming the ECU, but alas that option is not available.

 

[jestal]

I have the PCIII and it did make the throttle response better, it is NOT a cure. Yesterday I did about 500 miles on some of the curviest roads in the SE. Maintenance throttle is NOT clean, BUT it's OK AND no worse than any other FI bike I rode. Way better than stock. Although the G2 may be the best thing since buckwheat, but I'm not sure it's absolutely necessary, depends on your bike.
You did hit on one thing, PCIII is no way as good as programming the ECU, but alas that option is not available.

Have you considered tinkering with the PCIII map yourself? Maybe you have a leaner-than-most set of injectors and the cal in the PCIII is not quit enough.

From a fueling standpoint the PCIII is doing exactly what reprogramming the stock ECM would do so if reprogramming the fuel map in the stock ECM would be considered a "cure" then the PCIII would be a cure. It may be that the map supplied with the PCIII is not a perfect cure but the PCIII itself is capable of doing just about anything to the fueling map that you would need which would end up being a perfect cure.

If you don't have a laptop to hook up to the PCIII unplug it and bring it to your desktop and power it with the 9volt battery attachment to download the PCIII map. Go to the RPM areas you noticed some hesitation and add a bit of fuel to that general area of overrun conditions. Try it and see. As long as you are adding fuel in small amounts you cannot harm anything (no danger of leaning anything out too far anyway in the overrun areas) and if you save the existing map in the PCIII you can always go back to it. Play around. It's allowed.

While "reprogramming" the stock ECM might sound like heaven it would be pointless unless you knew exactly what the cal in the production ECM needed to be to eliminate the problem. Unless you are Yamaha this is likely as far as this discussion is going to get. No OEM would hand out the codes to break into the production ECM and the software and lookup table values needed. From a legal standpoint it is not allowed due to the emission laws. So even if someone were able to reprogram the production ECM from a technical standpoint you wouldn't be any further ahead unless you knew what to reprogram and were to reprogram it inside the ECM software and what program values to use. Lots of engine dyno time needed for the later to be perfect. The PCIII can do exactly the same thing by interrupting the production ECM signal to the injectors and replacing it with the injector signal modified by the PCIII. So, in effect, you are "reprogramming" the stock ECM by either adding or subtracting from the production ECM fueling calculated. The injectors do not care where the signal is coming from and neither does the engine. If the PCIII fueling curve is worked heavily it can provide exactly the same results that reprogramming the actual production ECM would have. No difference. The PCIII is a more powerful tool than you think. I can certainly be the cure for most any fuel related driveability problem if enough time is spent playing with it.

 

[temp357]

While "reprogramming" the stock ECM might sound like heaven it would be pointless unless you knew exactly what the cal in the production ECM needed to be to eliminate the problem. Unless you are Yamaha this is likely as far as this discussion is going to get. No OEM would hand out the codes to break into the production ECM and the software and lookup table values needed. From a legal standpoint it is not allowed due to the emission laws. So even if someone were able to reprogram the production ECM from a technical standpoint you wouldn't be any further ahead unless you knew what to reprogram and were to reprogram it inside the ECM software and what program values to use. Lots of engine dyno time needed for the later to be perfect. The PCIII can do exactly the same thing by interrupting the production ECM signal to the injectors and replacing it with the injector signal modified by the PCIII. So, in effect, you are "reprogramming" the stock ECM by either adding or subtracting from the production ECM fueling calculated. The injectors do not care where the signal is coming from and neither does the engine. If the PCIII fueling curve is worked heavily it can provide exactly the same results that reprogramming the actual production ECM would have. No difference. The PCIII is a more powerful tool than you think. I can certainly be the cure for most any fuel related driveability problem if enough time is spent playing with it.

When i took my bike in for service, the shop foreman mentioned that the ECU can be reporgrammed. But I agree, it's of little or no help to us without the codes or a dyno. The dealer would most likely never help with a modification of this sort due to legalities around emissions and it's of no value to us without the codes or a dyno to create a custom map. The one benefit however that you did leave out...reprogramming the ECU would give us the ability of leaving the o2 sensor connected. By leaving the o2 sensor connected, the ECU can adjust the mixture based on feedback and make appropriate adjustments for temperature or altitude. Without it, you have one map that will have to do in any condition you ride.

 

[DVMpete]

By leaving the o2 sensor connected, the ECU can adjust the mixture based on feedback and make appropriate adjustments for temperature or altitude. Without it, you have one map that will have to do in any condition you ride.

Makes sense intuitively to me, although I'm a very novice mechanic at best.....Anyone out there from Colorado (or other high altitude regions) who can comment on the performance of the PCIII at altitude?

 

[temp357]

Makes sense intuitively to me, although I'm a very novice mechanic at best.....Anyone out there from Colorado (or other high altitude regions) who can comment on the performance of the PCIII at altitude?

I've started at sea level and rode through the rockies. With a pciii and the o2 sensor disconnected, the bike runs overly rich at altitude...so much so that you can actually smell the gasoline in the exhaust. I assume the reverse would be equally true. Programming a pciii with a map for altitude, and riding it down to sea level would make the fi map very lean at sea level.

I guess the solution for that would be to get the pciii lcd unit and load different maps based on altitude and temperature...too bad the pciii can't accept the o2 sensor input and make the necessary adjustments.

 

[DVMpete]

Makes sense intuitively to me, although I'm a very novice mechanic at best.....Anyone out there from Colorado (or other high altitude regions) who can comment on the performance of the PCIII at altitude?

I've started at sea level and rode through the rockies. With a pciii and the o2 sensor disconnected, the bike runs overly rich at altitude...so much so that you can actually smell the gasoline in the exhaust. I assume the reverse would be equally true. Programming a pciii with a map for altitude, and riding it down to sea level would make the fi map very lean at sea level.

I guess the solution for that would be to get the pciii lcd unit and load different maps based on altitude and temperature...too bad the pciii can't accept the o2 sensor input and make the necessary adjustments.

Do you need a PC for the pcIII....or can you do things with a Mac?

 

[SkooterG]

I've started at sea level and rode through the rockies. With a pciii and the o2 sensor disconnected, the bike runs overly rich at altitude...so much so that you can actually smell the gasoline in the exhaust. I assume the reverse would be equally true. Programming a pciii with a map for altitude, and riding it down to sea level would make the fi map very lean at sea level.
I guess the solution for that would be to get the pciii lcd unit and load different maps based on altitude and temperature...too bad the pciii can't accept the o2 sensor input and make the necessary adjustments.

Well, I wholeheartedly disagree with that.

I too have run in all types of altitudes and my PCIII has performed flawlessly with nary a problem. I don't smell gas, and have no drivability issues. In fact I get much better fuel mileage at high altitudes, which if was running so rich, wouldn't happen. Your claim, doesn't make sense. The FJR has various sensors that measure environmental parameters, then feed that info to the ECU where it makes adjustments to the fuel injection, even with a PCIII installed. So with PCIII, or without, FJR should run fine at any altitude as the ECU is compensating for it. With NO PCIII installedd, the FJR will run fine without the O2 sensor connected as many have shown. Sensors adjust for temperature, and altitude. This is how many bikes ran by design before they started going to closed loop systems (w/O2 sensors) anyways.

No different maps needed. No O2 sensor needed.

 

[Bike Effects]

Makes sense intuitively to me, although I'm a very novice mechanic at best.....Anyone out there from Colorado (or other high altitude regions) who can comment on the performance of the PCIII at altitude?

I've started at sea level and rode through the rockies. With a pciii and the o2 sensor disconnected, the bike runs overly rich at altitude...so much so that you can actually smell the gasoline in the exhaust. I assume the reverse would be equally true. Programming a pciii with a map for altitude, and riding it down to sea level would make the fi map very lean at sea level.

I guess the solution for that would be to get the pciii lcd unit and load different maps based on altitude and temperature...too bad the pciii can't accept the o2 sensor input and make the necessary adjustments.

Do you need a PC for the pcIII....or can you do things with a Mac?

No Mac program. Can you say Windows emulation?

 

[temp357]

I've started at sea level and rode through the rockies. With a pciii and the o2 sensor disconnected, the bike runs overly rich at altitude...so much so that you can actually smell the gasoline in the exhaust. I assume the reverse would be equally true. Programming a pciii with a map for altitude, and riding it down to sea level would make the fi map very lean at sea level.
I guess the solution for that would be to get the pciii lcd unit and load different maps based on altitude and temperature...too bad the pciii can't accept the o2 sensor input and make the necessary adjustments.

Well, I wholeheartedly disagree with that.

I too have run in all types of altitudes and my PCIII has performed flawlessly with nary a problem. I don't smell gas, and have no drivability issues. In fact I get much better fuel mileage at high altitudes, which if was running so rich, wouldn't happen. Your claim, doesn't make sense. The FJR has various sensors that measure environmental parameters, then feed that info to the ECU where it makes adjustments to the fuel injection, even with a PCIII installed. So with PCIII, or without, FJR should run fine at any altitude as the ECU is compensating for it. With NO PCIII installedd, the FJR will run fine without the O2 sensor connected as many have shown. Sensors adjust for temperature, and altitude. This is how many bikes ran by design before they started going to closed loop systems (w/O2 sensors) anyways.

No different maps needed. No O2 sensor needed.

Skooter,

do yourself a favor and look up "closed loop fuel injection" in google or something.

 

[SkooterG]

Skooter,do yourself a favor and look up "closed loop fuel injection" in google or something.

Don't have to. I know what it is.

What's your freakin point?

 

[John_Dumke]

Am I missing something here?

Can't you, on the fly, adjust the PCIII in either the Low, Mid or High rpm range, and this will adjust the current map across the board.

So if you visit your friends in Colorado, you can lift up your seat and press a button several times and your good to go.

Haven't messed with this aspect of my PCIII yet, since I haven't needed to, but isn't that what those three buttons are for.

 

[SkooterG]

Can't you, on the fly, adjust the PCIII in either the Low, Mid or High rpm range, and this will adjust the current map across the board.
So if you visit your friends in Colorado, you can lift up your seat and press a button several times and your good to go.

Haven't messed with this aspect of my PCIII yet, since I haven't needed to, but isn't that what those three buttons are for.

Yup. But they only have a limited adjustment range. But in theory one use them for that purpose, but then you are only going by the butt dyno - none too accurate generally. I have used min to try an lean out the mixture for efficiency on trips, but I'm not really sure it has much of an effect.

I still say you don't need to. The FJR has a complicated fuel injection system that compensates for altitude even with the O2 sensor disconnected.