Yamaha Rhino Forum banner

1 - 14 of 14 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #1
I have a 2008 Rhino 700 with a reverse issue. When I shift to reverse it takes off as if the throttle is stuck but it is not as it does not happen in forward. It seems the more strain the more harder it hits the throttle automatically like backing up a hill. If I back up at an idle on a flat surface or even a bit down grade it seems fine, but anything over idle it seems to take off with a mind of its own. Governor issue maybe???? Anyone ever experience the same issue? Any help with a solution will be greatly appreciated.
 

·
Registered
Joined
·
3,650 Posts
I have a 2008 Rhino 700 with a reverse issue. When I shift to reverse it takes off as if the throttle is stuck but it is not as it does not happen in forward. It seems the more strain the more harder it hits the throttle automatically like backing up a hill. If I back up at an idle on a flat surface or even a bit down grade it seems fine, but anything over idle it seems to take off with a mind of its own. Governor issue maybe???? Anyone ever experience the same issue? Any help with a solution will be greatly appreciated.
I've never heard of that one before. It will move in reverse when you are at idle, as not having your foot on the pedal? Does it move at idle like that when you are in a forward gear as well?

Just for the sake of diagnostics, does the reverse indicator light on the dashboard come on when you are in reverse and go out when you are in all other gears (including neutral)? Any error codes showing up?
 

·
Registered
Joined
·
6 Posts
Discussion Starter #3 (Edited)
I need to feather the Throttle in reverse to get it to Move, it doesn't move with out any throttle. THe only way I can control it in reverse is basically Feather the throttle just above idle so it will move, but I have Tracks installed and most time I need a little more throttle and then it seems to have a mind of its own as if the throttle is sticking and like I said, if there is a strain on the engine like backing up hill the engine will try harder all on its own. Weird.... Works just fine in forward.

The reverse Light comes on or at least it did Until I grounded the Reverse switch (Troubleshotin) which didn't solve the problem other that Keeping the "R" light from coming on. No error Codes...
 

·
Registered
Joined
·
3,650 Posts
I need to feather the Throttle in reverse to get it to Move, it doesn't move with out any throttle. THe only way I can control it in reverse is basically Feather the throttle just above idle so it will move, but I have Tracks installed and most time I need a little more throttle and then it seems to have a mind of its own as if the throttle is sticking and like I said, if there is a strain on the engine like backing up hill the engine will try harder all on its own. Weird.... Works just fine in forward.

The reverse Light comes on or at least it did Until I grounded the Reverse switch (Troubleshotin) which didn't solve the problem other that Keeping the "R" light from coming on. No error Codes...
The 700 has an ECU (Engine Control Unit) which controls the fuel injected into the engine. I would suspect that there is something going on with the ECU or perhaps one of the sensors that it relies on. If you can beg, borrow or steal a known good ECU to swap out as a trial, you might find that doing the trick.

The reverse rev limiter does an altogether different thing, in that it cuts in at around 4000 RPM to keep the engine from revving any higher while in reverse. I cannot see it being involved in the symptoms that you are describing.

For what it is worth, that same reverse indicator light flashes to warn of a malfunctioning speed sensor, at least on the 660.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #5 (Edited)
I need to feather the Throttle in reverse to get it to Move, it doesn't move with out any throttle. THe only way I can control it in reverse is basically Feather the throttle just above idle so it will move, but I have Tracks installed and most time I need a little more throttle and then it seems to have a mind of its own as if the throttle is sticking and like I said, if there is a strain on the engine like backing up hill the engine will try harder all on its own. Weird.... Works just fine in forward.

The reverse Light comes on or at least it did Until I grounded the Reverse switch (Troubleshotin) which didn't solve the problem other that Keeping the "R" light from coming on. No error Codes...
The 700 has an ECU (Engine Control Unit) which controls the fuel injected into the engine. I would suspect that there is something going on with the ECU or perhaps one of the sensors that it relies on. If you can beg, borrow or steal a known good ECU to swap out as a trial, you might find that doing the trick.

The reverse rev limiter does an altogether different thing, in that it cuts in at around 4000 RPM to keep the engine from revving any higher while in reverse. I cannot see it being involved in the symptoms that you are describing.

For what it is worth, that same reverse indicator light flashes to warn of a malfunctioning speed sensor, at least on the 660.
Steve,
My Good Friend also has a 08' 700, I think I will Try his. Recently I left ran my battery completely dead and tried to boost it with an almost dead Booster Battery. Could I have messed something up in the ECU? Is there a way to reset it? I found the one Reverse Sensor, are there More?
 

·
Registered
Joined
·
3,650 Posts
Steve,
My Good Friend also has a 08' 700, I think I will Try his. Recently I left ran my battery completely dead and tried to boost it with an almost dead Booster Battery. Could I have messed something up in the ECU? Is there a way to reset it? I found the one Reverse Sensor, are there More?
Oh, yes, there are many sensors. For example, there are a bunch of sensors related to getting fuel into the engine and could be involved in the symptoms that you are describing. Intake air temp sensor, Idle speed control, Throttle position sensor, Coolant temperature sensor, Intake air pressure sensor, Speed sensor, and built into the ECU is the ability to monitor engine RPM by virtue of the ignition pulse coil. The ECU also is able to know when the machine is in reverse by virtue of the reverse sense switch that you had disabled.

What is strange is that this seems to be different between forward and reverse. Get that known good ECU in and that may tell us something.

BTW, get your battery fully charged and do not try to run the machine with it weak. There is some risk to the electronic brain of the machine with a seriously depleted battery and the voltage spikes involved with jumpering the battery.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #8
Steve,
My Good Friend also has a 08' 700, I think I will Try his. Recently I left ran my battery completely dead and tried to boost it with an almost dead Booster Battery. Could I have messed something up in the ECU? Is there a way to reset it? I found the one Reverse Sensor, are there More?
Oh, yes, there are many sensors. For example, there are a bunch of sensors related to getting fuel into the engine and could be involved in the symptoms that you are describing. Intake air temp sensor, Idle speed control, Throttle position sensor, Coolant temperature sensor, Intake air pressure sensor, Speed sensor, and built into the ECU is the ability to monitor engine RPM by virtue of the ignition pulse coil. The ECU also is able to know when the machine is in reverse by virtue of the reverse sense switch that you had disabled.

What is strange is that this seems to be different between forward and reverse. Get that known good ECU in and that may tell us something.

BTW, get your battery fully charged and do not try to run the machine with it weak. There is some risk to the electronic brain of the machine with a seriously depleted battery and the voltage spikes involved with jumpering the battery.
Steve, I tried the known good ECU and still exactly the same thing. Those sensor you spoke of earlier, where would you starting checking first?
 

·
Registered
Joined
·
76 Posts
Check the boot between the throttle body and head. If its cracked/ripped, check your motor mounts.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #10
Check the boot between the throttle body and head. If its cracked/ripped, check your motor mounts.
That was exactly what the problem was. The engine mounts broke and broke the boot at the throttle body. In forward operations it would twist the engine and close the crack in the boot so it would operate seemingly normal, in reverse the engine would twist and open the crack causing extra air to get through and the engine to REV the more strain the more twisting. Replaced boot and engine mounts and tested fine.

Thanks GUys
 

·
Registered
Joined
·
3,650 Posts
Check the boot between the throttle body and head. If its cracked/ripped, check your motor mounts.
That was exactly what the problem was. The engine mounts broke and broke the boot at the throttle body. In forward operations it would twist the engine and close the crack in the boot so it would operate seemingly normal, in reverse the engine would twist and open the crack causing extra air to get through and the engine to REV the more strain the more twisting. Replaced boot and engine mounts and tested fine.

Thanks GUys
Excellent. Thanks for reporting the solution to us.
 

·
Registered
Joined
·
616 Posts
Great job on describing issue and Steve's response - learned something today and that's always a good thing! 😊
 
1 - 14 of 14 Posts
Top