what mods can a busa handle without a PC??

[CAT3]

Page 4-31:
When the GPS Voltage drops below .6v for 3sec or more, Action is Gear Position signal is fixed to 6th Gear.

(this means the bike would not be able to rev beyond 10,200 rpm in any gear, since that is the 6th gear rev limit.) (also, means you would be restricted to 186 mph, which is programmed via 6th gear in the ECU).

Page 4-35:
Code C31, References the GPS, When the voltage drops below .6v for 3sec or more.

Page 4-37
C31 Code, when NO VOLTAGE IS PRESENT, OR VOLTAGE IS TOO LOW (UNDER .6V REMEMBER THIS?). Check Pink wire at ECU, is there more than .6v? NO = Bad GPS or open in the wiring for it. So, please go probe your pink and see what the voltage is with a TRE? I dont have one, as this seems to escape your memory, but my modded GPS gives the ECU more than .6v

So mine is not like the TRE in your opinion.

Page 7-18 will tell you how to test the GPS for V throughput. Please read it.

Page 7-20
Gear Position Switch:
The GPS has different resistance per gear and the ECM understands the GPS (in my terms it recognizes the resistance set for each gear) and selects the timing when the GPS gear is changed! Holy Shiate....WTF did that just say? A different value per gear, measured by resistance in ohms? No way. Oh yeaaass 2Busa, it is straight from your MANUAL!


Page 8-7 Troubleshooting
Engine runs poorly at high speed...check Gear Position Switch! Gee, why would it run poorly at high speed if it were such a great thing to do running in FSM? I know, you're working on a good logical reason for this one too

Page 8-7 Torubleshooting
Engine lack power..... check gear position switch! Read above, same applies.

Again, without you typing, show me, page and para. if you will, or pictorals work fine, he11 I like playboy just for the pics. I can type to you all day long w/o some kind of proof and you to me, neither of us will budge. Unlike you, I've read your words, tried some of things, and I have found that what you've typed doesn't seem to work as you say...I d/c my GPS and the bike runs like azz. Connect it, it runs fine. Different than what you claimed. So, do you acknowledge the GPS sends different resistance to the ECM so the ECM knows what gear it is in? If so, then you must admit your previous claim that it cannot use 5th gear twice, since it must have something to do with speed vs rpm etc. is bullshit, and the MANUAL says so FTW! Come on man, come off your ego feeding high horse and read what I've typed, and tell me your still 100% correct? If you were here, I'd print the manual out and slap you with until you agreed with me

 

[CAT3]

(2busa @ Dec. 16 2006,14:37) My deal is a challenge to myself. I'm wondering if I can show how a computer bike works and how to repair it. First, you need the basics. I'm more the abstract thinker being less technical, and explaining the complex into a more simple way of watching the, "action/reaction" way things happen between a sensor and computer.
We can all follow by downloading the shop manual.

2Busa... lets get back to this point, since it seems a much more friendly (on my part) and ready to learn point (on your part).
To make this less challenging, let me walk you thru the process, of just the GPS in relationship to the ECM, if you will please follow along.

The GPS, or Gear Position Switch, is a 7 position adjustable resistor basically. It has Neutral value in ohms, and a different ohm for each gear 1, 2, 3, 4, 5, and 6. Measuring the voltage at the pink wire of the ECM, we can verify there is more than .6v, with or without a modified GPS (MGPS, or TRE), as long as the harness is in fact in good repair. So, seeing there is .6v or more, we are not in FSM yet.

Next, measuring resistance in the black wire, grounding portion of the GPS, we will see there are 7 distinct values, one for each position of the GPS.

In a stock form, each gear (forget about N since we're not discussing it) has a set value, that when the ECM see's it, the ECM will say "hey, we're in x gear" which is positively correlated to that amount of resistance.

In a MGPS, each gear still has its own ohm value, except for 6th gear. 6th gear has been modified to match the resistance of 5th gear (normally, some I understand use 2nd gear or whatever). Now, when the GPS is moved from 5th to 6th, the resistance stays the same, and the signal sent to the ECM is the same. Thus, the ECM continues to think the bike is in 5th gear, allowing the rpm to max at 10,600 (rather than 10,200) and the speed restriction is no longer there. Again, the ECM is not sent into FSM at this point either.

Now, at this point, we've measured voltage at the ECM on the pink wire, and verify there is more than .6v. This means the wiring is intact, and there is continuity b/w the input and output side of the GPS. Also, it again means there is no FSM set because of low voltage. Remember the Manual only calls for too low or absolute lack of voltage to trigger the FSM C31 due to GPS Failure.

So how can we set the C31 code? D/c the GPS, or cut the wiring for it. Then the ECM will not see .6v and will resort to FSM.

How can we test on a BUSA the MGPS and its relationship to a failed GPS setting a C31 code?
1. Get to a dealer and see if C31 is set when using a MGPS. I have and no code is stored, not even C31 using my MGPS.

2. Measure the voltage at the ECM with a MGPS, you should see .6v or more, if not, the MGPS is faulty. Mine has always been more than .6v

3. Measure the ohms for each gear, noting that 5th and 6th gear position are sending the same amount of resistance to the ECM. *NOTE: Not all GPS are modified the same, as previously stated, it may be necessary to record each gear and annotate what 6th gear mathces. My 5th gear and 6th gear ohms are nearly identical, if not the same.

4. See if the FI Light is on. FI light is triggered when there is a hard code fault set in the ECM, like C31. My FI light is not, nor has it ever been on, other than functions check on startup.

Thats the basics right there for you. Hopefully this will clarify the ECM vs GPS function. And there is no other checksum for the ECM to determine what gear the bike is. If you match the ohm for 1st gear to be replicated when in 6th, you will still be able to speed beyond 186mph and or 10,200 rpms. There is no other method the ECM uses, like mph vs rpm vs anything else, simply put, it is up to the ECm to recognize the value from the GPS.

Once you have digested this, and referenced the manual, you will see the words are correct here, and then we can move on to discussing tuning, and the PC. That ought to be fun.

 

[2busa]

CAT, I don't own either a Busa or the 13.5. I'm going by what I read here and what I remember doing to the 13.5.
I did suck you into gps/speedo deal. Since the book only covers 2 years, I needed to see if later models were updated to read the C/S sprocket. True again, I had to edit the 15 sensors, but the point was to show the f-safe codes matching each component. You brought up the technical part, (less sensors) which was fine.

CAT, let me ask you this. When you disconnected the GPS, was this a stock bike or with a mapped PC in play at the time? I see your 'sig' list, but no PC? Did you add a PC and not add it to your sig? A GPS signal is all you'll receive for a code. That's your 6th map, be it spit or hidden.

When you hear riders connecting the tre, the first thing they notice is the lower end change. That means also, there is no coding going on as well, but it sure changed characteristics.

Do you agree that the instant difference can only be explained by defaulting to 6th fixed, because, yes, there is no code display. Yes, something did transpire and a digital signal is being used to create the tuning effects. Finally, you only touched the GPS, nothing else.

 

[CAT3]

(2busa @ Dec. 29 2006,01:36) CAT, I don't own either a Busa or the 13.5. I'm going by what I read here and what I remember doing to the 13.5.
I did suck you into gps/speedo deal. Since the book only covers 2 years, I needed to see if later models were updated to read the C/S sprocket. True again, I had to edit the 15 sensors, but the point was to show the f-safe codes matching each component. You brought up the technical part, (less sensors) which was fine.

CAT, let me ask you this. When you disconnected the GPS, was this a stock bike or with a mapped PC in play at the time? I see your 'sig' list, but no PC? Did you add a PC and not add it to your sig? A GPS signal is all you'll receive for a code. That's your 6th map, be it spit or hidden.

When you hear riders connecting the tre, the first thing they notice is the lower end change. That means also, there is no coding going on as well, but it sure changed characteristics.

Do you agree that the instant difference can only be explained by defaulting to 6th fixed, because, yes, there is no code display. Yes, something did transpire and a digital signal is being used to create the tuning effects. Finally, you only touched the GPS, nothing else.

2Busa...

In the earlier than this post you said no one see's that 6th gear is fixed if you d/c the GPS, yet I said it is. Just so we're clear, if you d/c the GPS or have a faulty wiring in one, the ECM will lock in 6th gear parameters, meaning there is absolutely no way in any gear you can rev beyond 10,200 rpms, afr will be slightly richer as well, and timing is reduced as well. If you didn't know, the timing table for 6th gear is a couple degree's below other gears so to avoid damage from detonation with high load low rpm (comparitvely low to the other gears that is), also known as FSM.

What you hear when plugging in the TRE I dont know. My MGPS didnt make any noise, and the only relationship to running different is in neutral, the bike idles slightly different. It is not however thinking it is in 6th Gear, as identified by a quick multimeter probe of the ground. Have the values changed, yes, but not to 6th gear. And it is also not operating in FSM at any time with the MGPS installed, unless a sensor quits!

No, I have not installed a PC on my bike. And I doubt I ever will. Tuning we'll chat about later if thats ok with you?

Yes, again, there is a difference in idle rpm clutch in/out, but again, IT IS NOT SHOWING IN THE ECM AS 6TH GEAR. The signal is not digital at this point. What is happening, is the current, V and O is altered slightly, still within the acceptable range, so when the ECM see's a different value but still w/i range it will add/subtract fuel or timing as needed. Its as simple as that.

2Busa, you have to agree, as its written in the book, that in 6th gear the RPM is fixed to be no more than 10,200rpm. The only way the ECM see's a gear is from the resistance value sent by the GPS, NOTHING ELSE TELLS THE ECM ITS IN ONE GEAR OR ANOTHER! So, it cannot possibly be in 6th gear FSM all the time simply from a MGPS/TRE installed. It is only a matter of the ohms slightly changing, most likely due to wiring being added, add wire, increase resistance, however slight, the ECM still see's it.

And yes, I have only added a MGPS, nothing else as for TRE, SH etc...

My mods are included in the sig, as well, the fork rebuild I currently completed with a how-to...I didn't list the forks since I got the parts from a local dealer and not from the .org, out of respect basically.

I hope this helps you see, as the manual states, connecting a properly modified GPS (unsure exactly what is inside the tre, so cant be 100% sure) will only show the same resistance for 5th gear when in 6th, and since the bike can rev beyond 10,200 rpm when nothing else is connected (TRE, SH etc...) then it CANNOT BE LOCKED IN 6TH GEAR FSM. Also, 6th GEAR FSM IS ONLY ENTERED WHEN: THE IS LESS THAN .6V FOR 3 SECONDS OR LONGER, THAT BEING A FAULTY GPS OR WIRING FOR A GPS.

 

[2busa]

Cat, you're describing things to me and I still have to deduce that the F/Safe is triggered. Again, watch how the idle has changed. Notice how even if you modify the GPS to a 5th signal resistance for 6th (to read a 5th signal again), you still have triggered the 6th fixed. The "new" idle should have sent a signal in your thought process. It triggered mine. Why can I say this? Because, your idle has changed too. You switched to a digital map. Just that slight resistance mod sent the ECM into the f/safe maps.
I can verify the same hidden (hard) codes that do not pop up on the 13.5's FI dash as well. Still, the whole bike has dramatically changed by the loophole wiring. I will have to conclude that the ECM defaulted to the 6th fixed. That is the only sensor you messed with. Mess with the sensor and the book will tell you 6th fixed will take over. Call it partial code harvesting. Just because the ECM didn't punch out a hard c31 code, none the less, the digital map is now running. Same digital signal used in the 13.5... a 6th gear map.

Show me how the idle changed. Show me how you can run 1 thru 4 in analog, then all of a sudden switch to the ECM maps when you hit the stock 5th and shift to to 6th gear so it reads the 5th resistance value (again). Show me why the idle changed? Didn't you say stock 5/6th values are all most identical?

You have me standing firm, CAT. I have not budged from the simple fact that 6th fixed took over from idle and locked down all 6 gears as well. The tre/clu mod uses 6th fixed. That's the only explanation I come up with... sans the hard code display.
I can only assume that the tre/clu mod both trigger the 6th fixed, because when the GPS does fail, the ECM defaults (see book) to the 6th fixed.

As far as the RPM's (400 extra rpm) change, The GPS is the component that needs the 6th fixed to work the 10.6 rev. Either you are running a full analog signal, (10.2 rpm), or default to the digital signal. No doubt we both see no codes set on display, but the bike is running on the digital fixed.

 

[2busa]

Technically, I (disconnected) harvested, (see pg. 4~31) the (2) 760mmHG maps, plus the 6th fixed maps. If I reinstalled one (760mmHG) signal back to analog, the "crisp" throttle response disappeared. If I added fuel, the (TPI) would smooth (rich-en) the, "f/safe crisp" right out of the throttle.

At partial analog/partial f/safe, I could break the rear tire loose with slight throttle application. I could not do that at full analog. Meaning, on the 13.5, I duplicated the tre... AND THEN SOME!

Because of my own testing (harvesting digital signals ~ ECU) on the 13.5, I can only conclude the 6th fixed is the only digital signal used for any mod to the GPS on the Busa.

It is no wonder this goes round and round. I'm past the 5th map BS. If you recognized the default to 6th in the book, this would stop right here and now. You are missing a better tune by running digital... as if the tre and clu mod are not chasing the "digital signal."

Until something like the tre/clu GPS mod reprograms the ECM to read 5th, (twice, no less) and not trigger the 6th fixed maps, you will never understand the ECM reads either the analog signal, the digital signal, or it's dies (ECM) itself.


CAT, the book says the bike will run if the GPS signal is lost. It's hard for me to fathom a bike runs that bad as you say. It is running the 6th fixed (like the tre) and shows a hard code.
PROFESSOR, (sorry) I have to use the 13.5 (computer) as the (identical) examples used for demonstration purposes.

 

[CAT3]

2Busa... I get everything your saying, difference is, your talking in circles around a subject you really dont understand as well as you think you do.

 

[2busa]

I keep trying to quantify the logic in simple terms. Maybe at this point you can see the two 'absolutes' that I see working in one of two modes inside the ECM.

Here is the example:

You can run a partial analog (outside sensors) signal, plus partial digital signal (f/safe inside ECM) and the bike will run all day long as per designed.... see pg. 4~31. But....

You cannot control the analog signal (with a 'plug-in' resistor) to force a given map (5th) to hold in place. It is like saying, "This tre/clu mod is going to tell the ECM to run in analog all the way up to 5th. The resistor now tells the program to recognize 5th and hole the 5th map one more time as I shift up to 6.

Have you recognized the way the computer locks you out from that 5th gear idea? Have you recognized the analog signal cannot be interrupted from bone stock. You cannot rev 10.6 in full analog. Still think you can reprogram the ECM's ROM to read 5th? 10.6 is in the digital, not the analog mode.
Computer bikes run full analog as designed, or default to digital. Those are the only two signal modes.

The line resistance, even the one wire wrapped around part of the main wire harness (out of ECU) for the CAN Communication to the Speedo/Dash; has to have so many winds, or communication is disrupted.
CAT's measurement reading 5th and 6th resistance being very close... shows how little it takes to trigger the default (digit) signal even at the GPS sensor.

Does any of this sound more logical as I walk thru the sensor vs digital signal? The computer is pre-programmed for 6th fixed maps. I do not see the instructions where I can re-program the ECM to hold 5th map as the default signal for all gears, let alone 5 and 6th, (see above).

Alter any analog signal, you will default to that f/safe map. Make sense yet? Still in the 5th gear camp?

 

[tommyboy]

The ECU cannot jump into all these odd modes you are talking about.

The ECU requires the IAP and IAT sensors as well as the RPM to infer what the intake air density is. The atmospheric sensor is used to sense altitude. The IAP sensor is the dominant one used to both infer air density and engine load. When you open the main throttle plate, the IAP senses the vacuum change that occurs. Without the IAP (MAP) sensor, the ECU is virtually "blind" and will be forced into limp home mode.

The TPS sensor is used to detect when you want to accelerate. If the IAP sensor were to fail, the TPS sensor can be used in limp home mode to determine approximate fueling required. Without the MAP sensor however, the ECU cannot determine air density or load changes such as hills or changing gears. If the bike has been modified extensively, the limp home fuel and ignition maps will be way off.

The coolant sensor is required to know when the engine has warmed up and when to pull back timing and fuel when the engine gets too hot. Without a knock sensor, this sensor is essential to setting a safe amount of timing advance.

 

[2busa]

tommyboy,

Component failure tumbles dead like this: Sensor ~ f/safe ~ ECU (fried).
No start condition fails in an either/or condition like this: ECU ~ Crank Sensor (one or the other failed/or both)

I will continue to revert to page 4~31, point out the f/safe (map) modes are fractionally close to each other as if in the analog mode. Think about it. How OFF are two maps? The digital (IAP) uses the 760mmHG map set. I will restate: There are two fu/adv stages. The idle to light load (a-N) method mapping and the mid to high (D-J) method maps. When the digital maps sign off from low method, back to high analog, you can't feel the transition... It is that subtle, I could not feel even a twitch of a difference. Meaning, my tune was in low speed method, (digital f/safe = 760mmHG) and in the analog signal; from mid range to WOT (TPS = analog sensor used).
I removed TPS and took a ride. Yes, I could ride it, and yes, it was full method, but not rideable per say; I must mention that.

Believe me, when I pulled the vacuum hose signal off the throttle body, I thought the rings were going to shatter under explosive detonation. I heard nothing. The more sensors I pulled off, the bike still kept running.

In theory, page 4~31 states the bike will (run) say, "YES" to 7 major sensors, if removed. Try one listed sensor at a time if you want to confirm the book stating the bike will run. Be my guest.

 

[2busa]

A quote from Russ (rceng.com)...
"Nobody at Honda seemed to know and, if they did, they weren't gonna tell us. After we started flow testing injectors, I found out Honda injectors were virtually all the same. Honda uses different pulse widths and pressures to provide different flow rates."

Like I keep saying; you are locked out of the ECM. You are locked out of the pump, (engine)... sans porting/cam degree, etc.
If I were to tune a computer bike knowing it's limits (over signal = pc map), and it's advantages (f/safe), then, I'd begin to tune the Busa with this approach:

1. Test; if fuel pressure (rise) alone, will out-perform the Pcom, (use oem injectors)
2. Incrementally increase the RC injectors (like an old jet change*)
3. Use injector size and fuel pressure combinations, (use the ECM's injector signal only).

The ECM plots the perfect spray. The Pcom throws darts ~That's the primal scream (from the dart) you hear on the net; to pass along another bad map. Think in the abstract and it is; a fat, over-rich blanket, draped over 4 perfectly plotted individual firing cylinders. ECM maps plot each cylinder. The Pc cannot (correct) an individual fire off. The one piston sequence you feel, (seat of the pants) is the misfire.
Take a V8 cylinder, a 4 cyl. or twin engine; there is going to be one cylinder firing off, and only one cylinder firing off. Read how many times (rotations under a second) you tag that (one pc map'd cylinder).

I'm learning FI/ECM little by little. I'm discovering the limits of the parts. What I continue to understand is the theory. Trying to explain it is another story. The theory works in the absolute. Even though I understand the concept, a simple sentence from Russ Collins, conked the (tuning idea) in my head. This to me; is a newly discovered tuning step.
Would you believe... I discovered this theory step this morning. Has the OEM injector assy ever been changed? Has anyone increased pressure at the fuel rail?
If I understand the computer/fuel theory up to this point, (tre trick ~ f/safe mode), you cannot tamper with the ECM, you can only set the "f/safe" or use the ROM to your advantage. The ECM is the fuel plot I want... sans the map headache disrupting the better ECM signal.

I did mention open loop was being used for a reason, but no one could explain why. I hope this (url below) guides you to (a better understanding) the fuel ratio limits "chart". Look around. Read the theory(s) why the Busa, (13.5) uses open loop.

It all makes (computer) sense to eliminate the Pcom as well. The disconnected sensor (replicates the tre/clu) trick, which sets a f/safe code; while the Pcom aims for a, 9 to 1 ratio. I continue to see the ECM locking me out. The aftermarket injectors (pulse/pressure), the exhaust design, and f/safe events are some of the ways I will tune a computer bike.

http://www.stealth316.com/2-calc-idc.htm A/F Ratio Chart, (yellow box). Read htm's.

*Does this sound like; if you add the Pcom, (on top of pressure/injector mods), you rich-en to 9.0:1? FI is a small precise window to soot 4. Agree/Disagree?

 

[8Daytona8]

Ok then! Is the PEU 33 digital luneir modulator mod worth it.

I know one thing! Open up the exhaust and MPG goes down the tubes. Back pressure is a needed thing for efficient burn. An extra 200 rpm in 6th gear never even crossed my mind.