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Anyone try to bypass/remove the idle speed control valve and use the adjustments on the secondary throttle valve for idle speed control? I'm working on it now just wondering if anyone else has tried.
 

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ISC valve ?? I have search the manual and can't find it. Show me a pic from the valve.

I have a set off bored out throttle bodies with the secundaire throttle plates removed.. And i'm in the proces removing the mechanisme from the secundaire throttle plates. My machinist is going to make a other housing for the STP sensor and a mechanisme to adjust the sensor to fool the ecu.
 

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Discussion Starter #3
It's number 11 on the microfiche pic. It connects with one large hose that pulls fresh air from the airbox and goes through a solenoid splits into two ports which dump into the throttle bodies.

My bike is an 07 california model with an 02 sensor and a different style of stv actuator.

 

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Mid `80's BMW cars use a setup that works the same way. I don't believe you could get the idle low enough by simply shimming the throttle plates, I'm not sure though.
 

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Why do you want to remove it, what's the benefit ?? on the K7 models the ecu controls the idle.

When you remove the ISC valve you get a malfunction code. You can not use the secundairy plates to controll the idle because they are controlled by the ecu, maybe with the lower throttle plates. When i run my bike (K3 (other throttle bodies as a K7))with the airbox off you can see that the secundairy throttle plates are not fully closed and you can see that the ecu adjust them.

But i can not see how you want to get it running properly, i think that the ISV valve also raise the idle on a K7 when the bike is cold.
 

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Discussion Starter #6
Why do you want to remove it, what's the benefit ?? on the K7 models the ecu controls the idle.

When you remove the ISC valve you get a malfunction code. You can not use the secundairy plates to controll the idle because they are controlled by the ecu, maybe with the lower throttle plates. When i run my bike (K3 (other throttle bodies as a K7))with the airbox off you can see that the secundairy throttle plates are not fully closed and you can see that the ecu adjust them.

But i can not see how you want to get it running properly, i think that the ISV valve also raise the idle on a K7 when the bike is cold.

Well I'm planning on removing the secondary throttle actuator and replace it with an adjustable vacuum diaphragm to control the mixture instead. That will put more emphasis on properly tuning the PC3 because the stva will thus have a smaller range it can adjust in, plus it will auto compensate for different atmospheric pressures.
 

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Well I'm planning on removing the secondary throttle actuator and replace it with an adjustable vacuum diaphragm to control the mixture instead. That will put more emphasis on properly tuning the PC3 because the stva will thus have a smaller range it can adjust in, plus it will auto compensate for different atmospheric pressures.
??

You want a vacuum diaphragm that controlls the secundaire throttle ??

I don't see how a vacuum adjuster is better than a electrical. Vacuum adjusting is slower and you can not controle it properly.

And when you remove the secondary throttle actuator you get al kind off problems --> FI light, no raised idle when cold, and maybe other problems.
 

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??

You want a vacuum diaphragm that controlls the secundaire throttle ??

I don't see how a vacuum adjuster is better than a electrical. Vacuum adjusting is slower and you can not controle it properly.

And when you remove the secondary throttle actuator you get al kind off problems --> FI light, no raised idle when cold, and maybe other problems.
I'm with our friend from across the pond. I don't see how replacing the stva with a vacuum actuator is going to help things. I would love to be proven wrong though.

As for monitoring atmospheric pressure, I believe the ECU already does that through the IAP (Intake air pressure) sensor and thus would modify the stva, injector pulse width, etc as needed. Does the PC3 not have the option of viewing that data and adjusting accordingly?
 

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Discussion Starter #9
I only like the vacuum modulator because it is adjustable and the stva is not. And as for it being slower, slower is a good thing, much of the sv's throttle sensitivity is directly related to the actuation speed of the stva.

And as for the pc3 options, i have only seen injector mapping and throttle pos, feedback. And the numbers for the injector map just seem to be some random set of numbers that seem to have no visible correlation to injector pulse width or duty cycle.
 

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I only like the vacuum modulator because it is adjustable and the stva is not. And as for it being slower, slower is a good thing, much of the sv's throttle sensitivity is directly related to the actuation speed of the stva.
Slower is not good, i want a fast throtlle respons it's a motorcycle and not a slow moped. The throttle sensitivity you can not change, lots off engine breaking, it's a Vtwin ;)
And as for the pc3 options, i have only seen injector mapping and throttle pos, feedback. And the numbers for the injector map just seem to be some random set of numbers that seem to have no visible correlation to injector pulse width or duty cycle.
The numbers on the PCIII are not random.
The numbers are the fuel setting (zero is the basic standard map).
When you raise the numbers you get more fuel (rich) and when you lower the numbers below zero you make it more lean.
 

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Discussion Starter #11
Slower is not good, i want a fast throtlle respons it's a motorcycle and not a slow moped. The throttle sensitivity you can not change, lots off engine breaking, it's a Vtwin ;)
You can change the throttle sensitivity, by controlling how quickly the cv system will allow the engine to build power. If the secondary butterflies are slower to open, then the engine hesitates a little more switching from idle to cruise/WOT

I'm not talking about inordinately slower, just slightly slower to smooth the throttle response. And the vacuum style air modulation bases it's adjustments on how the engine is actually performing and not on how it thinks the engine will perform based on a few air temp and pressure numbers.

On another note the electronics on SDTV FI are very expensive and degrade over time. When it comes time to replace all those nice little servos and sensors, you are looking at spending some $$$$$

The numbers on the PCIII are not random.
The numbers are the fuel setting (zero is the basic standard map).
When you raise the numbers you get more fuel (rich) and when you lower the numbers below zero you make it more lean.
I know they're not totally random numbers, but they are different on every bike, they just mean % of change from stock fuel map. I mean whats the duty cycle and inj. pulse width for cyl 1 at 25% throttle and 2500 rpm.
it would be kinda nice for more advanced users to be able to view more raw data feedback from the engine's sensors, gives you the ability to make finer adjustments to the tuning(down to 0.0001 volts on injector pulse and sensor feedback).

I am actually looking at ditching the entire FI system with the exception of the throttle bodies and injectors and using a universal fi controller that I have heard good things about.
Mega Squirt FI Controller -- http://www.msefi.com/index.php
 

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On another note the electronics on SDTV FI are very expensive and degrade over time. When it comes time to replace all those nice little servos and sensors, you are looking at spending some $$$$$
Anyone on this board had to replace these? Anyone? Randy with his 100000 mile SV?
I know they're not totally random numbers, but they are different on every bike, they just mean % of change from stock fuel map. I mean whats the duty cycle and inj. pulse width for cyl 1 at 25% throttle and 2500 rpm.
The PCIII screen will tell you the duty cycle, which it'll also log, if it interests you. But the reality is that the exact duty cycle isn't actually important... if you need more gas, you add it, if you need less, you take it away.
it would be kinda nice for more advanced users to be able to view more raw data feedback from the engine's sensors, gives you the ability to make finer adjustments to the tuning(down to 0.0001 volts on injector pulse and sensor feedback).
You'll gain no advantage by having that level of injector adjustment... a change that small wouldn't be measurable even on the nicest dyno.
I am actually looking at ditching the entire FI system with the exception of the throttle bodies and injectors and using a universal fi controller that I have heard good things about.
Mega Squirt FI Controller -- http://www.msefi.com/index.php
That'd be one option, but you'd have a hard time finding justification for it.
 

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Svbob, I guess I don't understand the desire for such precise control over the FI system. I could justify it more if these engine were more complex, i.e throttle by wire (which by utilizing the stva it kind of has), variable valve timing, variable length intake runners, some type of forced induction or N2O. Having independent control over those, real gains could be made in the performance department. As it stands, the ECU is really only in charge of injector pulse width and ignition timing. Does the PC3 allow changes to ignition timing? I don't see a knock sensor in the schematics, so I am not sure.

I can however, completely understand the desire to modify things. You seem to know what you are doing and if remaking the FI system from scratch is your idea of a good time, then GO FOR IT! I don't think most people here have such a desire, so our experiences and insight are probably limited.

As imdying's sig says "I want a hobby, not just a bike" Good luck to you. Let us know how it goes. Also, see if you can throw it on a dyno for some before and after comparisons. That would be interesting.
 

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Discussion Starter #14
the exact duty cycle isn't actually important
No way. Duty cycle shows how hard your injectors are actually working, and is a useful number in determining when to go up a size.
 
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