Yamaha Rhino Forum banner
1 - 20 of 22 Posts

·
Registered
Joined
·
187 Posts
Discussion Starter · #1 ·
Does anyone have experience with the idle speed control valve and how it should react? I've been having intermittent high idle problems and have tried quite a few things and cleaned it well.

When I turn the key on, with the ISC removed, it just buzzes and the valve vibrates. I've heard it should move in and out, just thought i'd throw it out there.

Also, this is a shot in the dark. Does anyone have one sitting around that they would be willing to sell me separate from the throttle body? I've had mine slightly bored and don't need the full TB.
 

·
Registered
Joined
·
271 Posts
Does anyone have experience with the idle speed control valve and how it should react? I've been having intermittent high idle problems and have tried quite a few things and cleaned it well.

When I turn the key on, with the ISC removed, it just buzzes and the valve vibrates. I've heard it should move in and out, just thought i'd throw it out there.

Also, this is a shot in the dark. Does anyone have one sitting around that they would be willing to sell me separate from the throttle body? I've had mine slightly bored and don't need the full TB.
Carl, try looking into finding an ISC from either a 01-04 Mitsubishi Eclipse, Galant 2.0 from an autowrecker. I'll try and find a part number to be more specific, but the ISC on the RHino is not a "one off" part, it was borrowed from an existing design, I just need to find the part number for you (and vodka right now prevents me from doing that ;)


Looks eerily similar, doesn't it? ;)

But, is your digital display throwing a code?
 

·
Registered
Joined
·
187 Posts
Discussion Starter · #4 ·
Kronic,

I did try the eclipse ISC valve - they are very similar but the plastic tip is too wide. No need to search any longer. The Suzuki King quad ISC is exactly the same and fixed the problem. Sorry it took so long to write the resolution. I've been on 3 dune trips and the problem appears to be fixed.

Carl
 

·
Registered
Joined
·
187 Posts
Discussion Starter · #6 ·
From what I remember, that's the part number. Actually, I had this part number saved... 13520-31G00, just one more character than yours.
 

·
Registered
Joined
·
357 Posts
are you saying your idle will just stay up around 2000 every once in awhile, then bee fine the next day, thats been my issue since i built my motor
 

·
Registered
Joined
·
1,367 Posts
It's possible that the throttle shaft may be leaking. these ATV throttle bodies do not seal off the throttle plates like auto motive. if there is too much uncontrolled air getting by the throttle plate then the IAC can't close off enough air to get the idle speed down.
Check to and see if plugging the IAC Bypass port brings down the idle speed if not, then you should disassemble the butterfly assembly replace the seals you can use "O" rings 2 per side if they fit.
see if that gets things under controll.

If plugging the bypass port does bring down the Idle speed then the IAC motor is not doing it's job may be the cause Or(least likely) is not getting a proper command from the ECM
 

·
Registered
Joined
·
3 Posts
I'm having the same problem. You mentioned the ISC may not be getting the correct signal from the ECU, but the service manual doesn't tell you what signal you should be getting. Can anyone tell me what they get on their 2008 700 at the ISC? There are 6 wires going to the ISC, two are battery voltage, two more I get grounds, and two I get nothing. If I knew that was normal I'd order the ISC. Thanks for the help!
 

·
Registered
Joined
·
1,727 Posts
I'm having the same problem. You mentioned the ISC may not be getting the correct signal from the ECU, but the service manual doesn't tell you what signal you should be getting. Can anyone tell me what they get on their 2008 700 at the ISC? There are 6 wires going to the ISC, two are battery voltage, two more I get grounds, and two I get nothing. If I knew that was normal I'd order the ISC. Thanks for the help!
You're not going to be able to check any inputs to the ISC valve unless you have an oscilloscope. You would be better off to try to borrow a valve from a friend to see if it corrects the problem.
 

·
Registered
Joined
·
643 Posts
the isc motors do fail. when i swapped out to a billet throttle body the isc was eliminated and idle was perfect. So when I went back to a yamaha throttlebody I siliconed the isc air bypass closed and used the butterfly stop screw to set idle speed. now it has a flawless idle.
 

·
Registered
Joined
·
3 Posts
Thanks for the quick replies!! When you say butterfly stop screw, you mean the adjustment screw right over the triangle shaped housing where the throttle cable goes in? I did stuff a rag in the hole where the ISC sits last night, and adjust that screw, and it does idles fine, I just worry that the TPS might not like seeing that plate not return to idle, and throw a code. Thanks!!!!!
 

·
Registered
Joined
·
1,378 Posts
Good info. guys, when you say "idle issues" how exactly was it acting.
Mine doesn't like to idle whether it's cold or warm. It'll idle for a few seconds then dies if you don't give it some throttle. When it is idling it's like it's laboring and barely able to keep up.
Also after a hard run when you lift off the throttle it sometimes takes a few seconds for it to return to idle.

Just wondering if this could be my problem and not my mapping.


Sent from my iPhone using Tapatalk
 

·
Banned
Joined
·
833 Posts
check out our vid on more hp....we had high idle issues only half the time on the trail and adjusted the tps,throttle stop and changed this and fixed our problem
 

·
Registered
Joined
·
1,378 Posts
Thanks James, I'll give it a look.
 

·
Registered
Joined
·
187 Posts
Discussion Starter · #16 ·
I had some amazing advice from Lyle at velocity devices and I'll post some of his comments regarding the issue I was having - he was spot on. Basically, my rhino was starting fine, then idling very high. Here's what he said was going on:

"When you turn on the key, the ISC valve should fully open (that lets air flow around the throttle blade for starting). Once the engine starts, the ECU will monitor the engine RPM, and fiddles with the valve to try to maintain that RPM (1600RPM for the Yamaha's). If the ECU cannot control the valve, then it can get "blown" open from the intake pressure, causing the RPMs to start to rise."


Here's an explanation on how to test the stepping motor to see that it works.
The way the ISC valve works is there is 2 windings with center taps. So looking at the connector with them 3 pins in a row, the center pin top and bottom are both +12V. The ECU then grounds one of the windings at a time to make the motor spin.

Problem is they need to be activated in sequence to make it extend/retract. The motor is a "stepper" motor, and by doing the windings in a certain sequence allows you to turn the motor 90 degrees at a time and hold position.

I think you need to spin the motor to get that pintle valve part to spin out. If you could, you should be able to ground each of those 4 windings, and see the motor turn 90 degrees. If memory serves me correctly, you should be able to apply +12V to the center two pins, and then ground the outside 4, one at a time in a circle pattern (IE top left, then bottom left then bottom right then top right). If you keep doing that, it should keep turning 90 degrees each time, and make the valve move in or out). Repeating in the opposite direction will make it spin the other direction.


He also gave me good advice about testing the TPS:
The voltage between the center terminal and one of the outside terminals will go from ~1V at throttle closed to ~4V at throttle full open. It should change smoothly from throttle closed to throttle open (no jumps, etc). The two outside terminals on the TPS are 5V and ground, so if you measure between the wrong one and center, the reading will be reversed.


BTW - I asked his permission to quote him - That guy has immediate responses and I absolutely love the VDI - I've been able to program my rhino through every mod I've installed and Lyle (owner of Velocity Devices) sometimes gets back to me via email within minutes.




 

·
Registered
Joined
·
1,378 Posts
Thanks for the info. Carl
 

·
Registered
Joined
·
643 Posts
Thanks for the quick replies!! When you say butterfly stop screw, you mean the adjustment screw right over the triangle shaped housing where the throttle cable goes in? I did stuff a rag in the hole where the ISC sits last night, and adjust that screw, and it does idles fine, I just worry that the TPS might not like seeing that plate not return to idle, and throw a code. Thanks!!!!!
It wont throw codes. I ran mine with no isc plugged in for quite some time. Also whenever changes are made to the throttle stop i always reset tps to .68, i set idle speed and tps at the same time as they effect eachother. You really dont need the isc at all. Mine would cycle at key on but would randomly quit working causing extreme high idle.

Sent from my PC36100 using Tapatalk
 

·
Registered
Joined
·
3 Posts
So I plugged the ISC port last night, and set idle speed, and ran the bike. First time as I bought it used. It ran great till about 30 mph then a little bit of light missing. Is it possible that's due to the TPS being off a little at start up? What wires do I check for the .68 volts on? And I take it the digital display does not offer a tach?
 

·
Registered
Joined
·
107 Posts
So when I take my ISC out and turn on the key it doesn't do anything. It does however get warm to the touch. BTW my rhino will not start at all. does that mean my ISC is bad or what??
 
1 - 20 of 22 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top