PC III

For my own understanding:

Radman discussed the 1 or 2% matched fuel injectors and how that made a big difference in smoothness. Also discussed in that thread was the CO settings and why the settings vary so much (stock) and that matching the injectors "should" allow the settings to be = or close. Here's my question......

When you disconnect the O2 sensor and install the PCIII, does the PCIII adjust the fuel/air mixture individually thus, in effect, "matching" the injectors? If so, it would seem that installing the PCIII negates the requirement for matching. A follow-on if I may your Honor, if the PCIII doesn't do this, then WTF!

Thanks.

O2 sensor has ABSOLUTELY nothing to do with matching fuel injectors. Matching (or non-matching) injectors is all compensated for by the ECU via the CO settings and the display. When the O2 sensor adjust fueling, it does it the same amount to all cylinders.

With all respect to Radman and his apparent success 'just zeroing out the preset FI CO settings", the ONLY correct way to properly adjust each individual cylinder's mixture (whether matched injectors or not) is to install riv-nuts in each header tube, connect them to an Exhaust Gas Analyzer, and then individually 'trim' each cylinder.

With the PCIII, I am pretty sure you CAN trim each cylinder individually with it's programming, but once again, unless you are using an EGA to actually measure what each cylinder is doing, how do you know what you are changing? So unless you are using an EGA, I wouldn't be messing with that.

Skooter - I am a curious cuss so I'll continue (thanks for your reply by the way)... and if you don't mind playing the "teacher,"-

- What does the O2 (I know, oxygen but where and "why") sensor measure and what does it do with the information - does it just "measure," or will different readings relative to parameters cause the ECU to change something?

- What does the CO setting measure/do? (Again, fuel/air?) And what I'm understanding is that there isn't any "auto" adjustment of the CO setting either by the PCIII or the ECU.

- In Rad's post it sounded like the CO settings were made (and different for each cylinder) to compensate for the differences in the injector performance - is the injector the sole contributer to the differences or are there other factors that contribute.

- I get that the EGA is the only accurate way to measure CO and to accurately make/change the settings.

Yeah, I'm a pain in the ***. I understand fuel/air/spark and the basics of 4 cycle engines. It's the painful details I'm fairly ignorant of. If you, or other folks in the know, don't have the time or inclination to instruct, I'll buy a book! Thanks for your time.

Jim

If you get back to basics for a moment..... The ultimate situation would be for each cylinder to get exactly the same amount of air and fuel. One would like perfect fuel distribution AND air distribution to each cylinder. In reality this is very difficult to achieve. Fortunately the engine doesn't care THAT much.... :lol:

If each port and throttle body and zip tube in the air box was perfect and symmetric and the inlet to the airbox was symmetric to all cylinders then the engine would stand a better chance of getting perfect air flow to each cylinder. They aren't, it isn't and it is almost impossible to package such a system so the result is that each cylinder flows just a little bit differently. This immediately builds in a cylinder-to-cylinder mismatch in airflow. Fortunately this can be predicted to some extent as a lot of it is dependent on the design parameters and it is repeatable...i.e...the inner zip tubes are always going to be different from the outer zip tubes in an FJR air box. It can also be minimized in the design....note that the inner tube of the air inlet goes well into the airbox causing some to think all the air cleaner isn't being used.

BTW.....The zip tubes are the tubes from the throttle body that extend into the airbox taking the throttle body inlet to the common plenum area inside the airbox.

Similarily, to get perfectly the same fuel flow from each injector requires a fuel rail with no "water hammer" effect (see previous post), injectors that all flow the same, matching injector drivers in the ECM, etc. Since the injectors are removeable and can be meddled with they are a good target for improvement. Injectors are usually +/- 3 % on an industry basis so something that can be done to make sure the deck is stacked in your favor for good fuel distribution is to flow the injectors and "match" the flow rating of the set as close as possible. Realize that any given engine is HIGHLY unlikely to have a + 3% injector next door to a -3% injector. Within any given time frame injectors being manufactured are pretty close together but an injector taken off the line 6 months before another injector might indeed be 6% apart in flow and BOTH would be "in spec".

The CO adjustement in the FJR ECM is a means of matching individual cylinder air flow to fuel flow by adjusting the pulse width of individual injectors....by just adding in a separate fudge factor for each cylinder pulse width. By putting in a CO probe and actually looking at the output of each cylinder the effects of injector matching, mismatched air flow, etc. can all be compensated for with the indivdual cylinder CO adjustment.

Yamaha can build in some known CO adjustement based on known differences in air flow and/or injector differences. How they do that is an unknown to me but the potential is there.

Things like the correction from the O2 sensor in put is a gross engine correction. All the injectors get a plus or minus correction factor, not something that is done on a cylinder basis.

Similarily, the PCIII just adds or subtracts to the base fuel map for the entire engine. I don't remember any provisions for adjusting cylinder-to-cylinder differences with the PCIII but my memory is too short for practical operation. The PCIII instructs to disconnect the O2 sensor so that the closed loop system in the ECM cannot start trying to remove the extra fuel just added. But it doesn't say anything about zeroing the CO adjustment for cylinder-to-cylinder balance so I don't think there is any overt action on the PCIII's part to match individual cylinders.

Correction: Actually I do remember a cylinder trim option on the PCIII that allows individual cylinder fuel trim. This would function (theoretically) the same as the FJR factory CO adjustment except the PCIII function applies at all engine speeds, not just idle/low speed like the factory CO trim feature. My bad. See...I told you my memory was for ****.

If one were to achieve a perfectly matched set of injectors it would be a pretty good assumption that the need for individual cylinder CO compensation would be negated. One of the driving forces for the CO matching was just eliminated. BUT....there is still that nagging problem with air flow inbalance cylinder-to-cylinder that matching injectors has nothing to do with nor does nothing to correct. THAT would/could be compensated for in the CO adjustement and would be negated by zeroing out the CO adjustement and relying purely on the hardware matching.

The mismatch in cylinder-to-cylinder airflow at idle and low throttles is pretty small so it is pretty much a moot point but should still be considered in the whole arguement. The injector flow differences are probably the prime player here so matching them gets most of the attention. Certiainly, if the CO settings were pre-set for a given set of "mis-matched" injectors then resetting the CO offset to the same value for all cylinders would be desireable if the injectors were matched.

Keep in mind that injectors can be "matched" at various pulse widths. Common in the industry is to just trip the injectors open fully and measure the max flow ratings and match the injectors accordingly. At idle, when the injector pulse width (or "on time") is small, the injectors could still be terribly mismatched due to the operating characteristics of the injector when it is opening and closing. Full flow matching does not take this into account so a decent injector flow match would include low pulse width flow measurement and matching.

When all is said and done the only REAL way to absolutely KNOW is to put the bungs in the pipes and measure CO on each cylinder and adjust accordingly. Anything else is a guess....maybe a good guess...but a guess nonetheless.

JimLor said:

For my own understanding:When you disconnect the O2 sensor and install the PCIII, does the PCIII adjust the fuel/air mixture individually thus, in effect, "matching" the injectors? If so, it would seem that installing the PCIII negates the requirement for matching. A follow-on if I may your Honor, if the PCIII doesn't do this, then WTF!

Thanks.

Click to expand...

No, it doesn't. The PCIII takes the signal generated by the ecm, and alters it. In essence, the PCIII map is only as good as the bike it was made on, if the base bike was messed up, all bikes that use the map will also be messed up. The O2 sensor measures the amount of oxygen remaining in the exhaust stream, and the ecm alters fuel mixture to bring it to a specified level. So far, all I can tell from my experiments is that the CO adjustment is for injector variances only. Nothing else makes sense, since the numbers seem to vary a lot amongst the field, and I can think of nothing else in the system that would need a cylinder by cylinder adjustment. MAP, TPS, Fuel Pressure, Ign Curve, Ambient Temp, all are common to all 4 cylinders. Only the throttle plates and the injectors are unique to each cylinder, and the throttle plates have their own adjustment built in. For those who are interested, further news on the 0 Injector experiment are-

1) Best CO setting is at 4 on each cylinder.

2) Idle quality suffers higher than this-idle hunts slightly at anything over 6

3) CO setting affects the ENTIRE rpm range

4) Set too lean, and throttle response suffers, as well as cold engine driveability. Engines hesitates when accelerating, not badly, but a definite lag as power comes on like a turbo would.

5) Set too rich, and vibration begins to set in, primarily in the already troubled 4000-5000 rpm range. This is how I know the CO setting affects engine performance beyond the much believed 3000 rpm point.

The O2 sensor measures excess oxygen in the exhaust. If combustion is complete then there is no excess oxgen. If it is incomplete then there will be excess (or unused) oxygen in the exhaust gas stream. The natural assumption is that if there is lack of fuel (lean) this will lead to excess oxygen. Similarily, too much fuel (rich) will lead to no excess oxygen. Simple O2 sensors like the FJR just tell the ECM that the exhaust is rich or lean of stochiometric (14.7:1). The ECM has logic built into the operational software to take that simple rich/lean info and do something with it to adjust the fueling to acheive 14.7:1. Understand that the engine would not be run at 14.7:1 deliberately by the guys that set it up EXCEPT for the fact that the catalytic converter will ONLY work if the engine is EXACTLY at 14.7:1. At 14.7:1 maximum conversion efficiency of the cat is possible so it is very desireable to keep the engine at 14.7:1 when conversion is required. Hence the O2 sensor.

The best analogy for the engine's closed loop fuel control system is to imagine yourself standing in the shower. You can only say HOT or COLD in a calm voice no matter whether the water is freezing or scalding or just right. Someone else has their hand on the hot/cold water control. Your task is to design a logic stream to enable the person holding the knob to do something when you say HOT or COLD to achieve the perfect balance of water temperature. Hot and cold relate to rich and lean. You relate to the O2 sensor. The logic you develop relates to what is in the ECM software and is the answer to your question of "how does it do what" with the information from the O2 sensor. That logic is proprietary for each OEM and carefully guarded. He who does best with air/fuel control does best with emissions and has a leg up for performance variation.

radman said:

JimLor said:

For my own understanding:When you disconnect the O2 sensor and install the PCIII, does the PCIII adjust the fuel/air mixture individually thus, in effect, "matching" the injectors? If so, it would seem that installing the PCIII negates the requirement for matching. A follow-on if I may your Honor, if the PCIII doesn't do this, then WTF!

Thanks.

Click to expand...

No, it doesn't. The PCIII takes the signal generated by the ecm, and alters it. In essence, the PCIII map is only as good as the bike it was made on, if the base bike was messed up, all bikes that use the map will also be messed up. The O2 sensor measures the amount of oxygen remaining in the exhaust stream, and the ecm alters fuel mixture to bring it to a specified level. So far, all I can tell from my experiments is that the CO adjustment is for injector variances only. Nothing else makes sense, since the numbers seem to vary a lot amongst the field, and I can think of nothing else in the system that would need a cylinder by cylinder adjustment. MAP, TPS, Fuel Pressure, Ign Curve, Ambient Temp, all are common to all 4 cylinders. Only the throttle plates and the injectors are unique to each cylinder, and the throttle plates have their own adjustment built in. For those who are interested, further news on the 0 Injector experiment are-

1) Best CO setting is at 4 on each cylinder.

2) Idle quality suffers higher than this-idle hunts slightly at anything over 6

3) CO setting affects the ENTIRE rpm range

4) Set too lean, and throttle response suffers, as well as cold engine driveability. Engines hesitates when accelerating, not badly, but a definite lag as power comes on like a turbo would.

5) Set too rich, and vibration begins to set in, primarily in the already troubled 4000-5000 rpm range. This is how I know the CO setting affects engine performance beyond the much believed 3000 rpm point.

Click to expand...

Rad, there is a cylinder trim feature in the PCIII that I forgot about also. IF USED this could trim each cylinder to account for injector mismatch and airflow mismatch I think. It isn't automatic with installing the PCIII but it is there. That feature is pretty difficult to use correctly without significant dyno work and significant cylinder-to-cylinder EGT or exhaust gas analysis so it is not enabled with the factory settings on the PCIII but it is there.

Are you sure that the CO trim works thru the entire RPM range? I don't know personally but I assumed from information otherwise that it was for low speed operation only. If it were used all the time the O2/closed loop would tend to null out the effect to some extent I would think. I never tried cranking the CO adjustment up as high as it sounds like you did so it very well could cover the whole speed range but unless the O2 were to be disconnected the ECM would learn out any CO offset at higher speeds I would think.

I agree that the most obvious and probably overwhelming reason for the CO balance or cylinder-to-cylinder offset is the injectors but the fuel pressure spike issue within the rail (from the water hammer effect) could also come into play on the later model bikes with returnless fuel rails. The individual cylinder air flow imbalance due to slight tuning changes due to the mismatched cylinder air flow paths could also have an effect and necessitate the CO balance feature.

Jim,

You have to promote the "map" to "advanced" in order to maintain separate tables for each injector/cylinder. At that point the injectors can and must be adjusted individually. This would also require header taps for EGA readings on each cylinder. and a fairly comprehensive dyno setup.

So the short answer is Yes, the PC-III can eliminate the need for matching injectors. But it will still require extensive diagnostic setups and equipment to effectively do so.

IMHO, the end result using advanced mode on the PC-III, would be far superior to simply matching the injectors. Because it would take into consideration many other variables unique to each cylinder.

But I'm too busy changing tires and having fun to bother with splitting that many hairs!



Jeff

Thanks to you all - today is a succes as I've learned something about the bike! And as I was telling someone earlier today (ref jestal), Stoichiometry rests upon the law of conservation of mass, the law of definite proportions (i.e., the law of constant composition) and the law of multiple proportions. In general, chemical reactions will combine in definite ratios of chemicals. Since matter cannot be created or destroyed, the amount of each element must be the same throughout the overall reaction. For example, the amount of element X on the reactant side must equal the amount of element X on the product side.

Stoichiometry is often used to balance chemical equations. For example, the two diatomic gases hydrogen and oxygen can combine to form a liquid, water, in an exothermic reaction, as described by Equation A.

(A) H2 + O2 → H2O

Equation A does not depict the proper stoichiometry of the reaction—that is, it does not reflect the relative proportions of the reactants and products.

( B) 2H2 + O2 → 2H2O

Equation B does have proper stoichiometry and is therefore said to be a "balanced" equation, depicting the same number of atoms of each type on each side of the equation. There are four H on the reactant side and 4 H on the product side and there are 2 O on both sides as well; mass has been conserved.

The term stoichiometry is also often used for the molar proportions of elements in stoichiometric compounds. For example, the stoichiometry of hydrogen and oxygen in H2O is 2:1. In stoichiometric compounds, the molar proportions are whole numbers (that is what the law of multiple proportions is about).

Compounds for which the molar proportions are not whole numbers are called non-stoichiometric compounds.

Stoichiometry is used not only to balance chemical equations but also is used in conversions—i.e. converting from grams to moles, or from grams to milliliters. For example, if there were 2.00 g of NaCl, to find the number of moles, one would do the following:

In the above example, when written out in fraction form, the units of grams cancels out, leaving one with the amount of moles (the unit that was needed), as shown in the following equation:

Stoichiometry is also used to find the right amount of reactants to use in a chemical reaction. An example is shown below using the Thermite reaction:

Fe2O3 + 2Al → Al2O3 + 2Fe

So, to completely react with 85.0 grams of Iron (III) oxide, 28.7 grams of Aluminum are needed.

Actually that's from Wikipedia!

As usual, when Jestal and Rad get together, lots-o-great info comes a flowing......thanks guys! :clapping:

jestal said:

Are you sure that the CO trim works thru the entire RPM range? I don't know personally but I assumed from information otherwise that it was for low speed operation only. If it were used all the time the O2/closed loop would tend to null out the effect to some extent I would think. I never tried cranking the CO adjustment up as high as it sounds like you did so it very well could cover the whole speed range but unless the O2 were to be disconnected the ECM would learn out any CO offset at higher speeds I would think.

Click to expand...

I do believe that the CO trim affects the 'base' injector timing only. So it has greatest effect at idle and low throttle/rpm settings. It shouldn't have much effect at higher RPM and larger throttle openings. At higher throttle/rpm, injector timing is predominantly determinted by those parameters and base timing is only a miniscule part of that. From memory, I believe the FI curves in the service manual show that to be true. So I am not sure how radman is feeling that across such a broad range. His butt dyno must be better than mine. His man-****s most definitely are! :lol:

jestal said:

Rad, there is a cylinder trim feature in the PCIII that I forgot about also. IF USED this could trim each cylinder to account for injector mismatch and airflow mismatch I think. It isn't automatic with installing the PCIII but it is there. That feature is pretty difficult to use correctly without significant dyno work and significant cylinder-to-cylinder EGT or exhaust gas analysis so it is not enabled with the factory settings on the PCIII but it is there.

Click to expand...

There is a cyl trim feature, but it's not available in the Dyno software I have. Either it's not available on all applications, or there is another download or software version that has it. My version isn't old, but in any case, it's not there.

Are you sure that the CO trim works thru the entire RPM range? I don't know personally but I assumed from information otherwise that it was for low speed operation only. If it were used all the time the O2/closed loop would tend to null out the effect to some extent I would think. I never tried cranking the CO adjustment up as high as it sounds like you did so it very well could cover the whole speed range but unless the O2 were to be disconnected the ECM would learn out any CO offset at higher speeds I would think.

Click to expand...

I haven't cranked the CO up anywhere near where it was from the factory. Roughly, the factory sets were 1)-1, 2)+14, 3)+24, 4)+18, or something like that. I now have all 4 injectors at +4, with excellent results so far. Changing CO definitely altered mid to high speed behavior as well as below 3K. They may well use the O2 to alter the mix, hence the belief that CO settings are null after the 3K mark is reached, as the O2 would be used as you stated-to maximize converter efficiency/operation.

Edit: Just upgraded from version 3.1 to 3.2 on the Dynojet software-individual cyl trim options still don't show, so I would have to guess this option isn't available for the FJR, at least the Gen I version.

Some times I forget that intention, tone, inflection, etc doesn't come thru on emails and the written word and some well intentioned and good-natured posts may be taken as a smart *** reply. My previous post was not meant with any sarcasm. I really do appreciate the time and effort you all take to answer my questions. I also appreciate picking up new words and concepts to me (like Stoichiometry - something I probably learned and forgot!) and finding out what the heck they mean.

Again, thanks for the discussion and replies. :clapping:

Hey Radman

The cylinder trim feature may require you to be connected to the PCIII unit in order to be listed as an option in "Power Commander Tools" menu.

I just checked it on my desk top and sure as hell it ain't there, but I have used it when connected to my bike. Maybe I will hook it up later to verify this lie.

Great thread by the way. Just as I could not believe the difference the PCIII made, I'm thinking the balanced injector thing may be worth a look. Smooth is good, smoother is better.

Zoltan