Bogs at 6800 RPM

[Rickb1b]

Guys I've read all the threads and can't find any information on this type issue, so any help is greatly appreciated.

I've got a 06 900. It just recently had the top end rebuilt and now it has a bog at 6800 RPM.

It doesn't bog like a stutter, it just stops pulling at 6800 RPM. It will not go past 6800. It pulls hard all the way up to 6800, it starts and idles fine. The plugs are good and have the perfect color. It does it both cold and hot.

It feels exactly like it has a governor which is not allowing it to go past 6800 RPM.

Any thoughts.

 

[94fordguy]

Have you checked to see if your power valves are clean and moving freely/normally?


Also, along those same lines another way to check the power valve operation is to disconnect the power valve solenoid from the system by unhooking the rubber lines and hooking them together or simply putting a small bolt int he lines to plug them. (don't completely remove the solenoid, it is needed by the ecu)

I would check/clean them first and if its still doing it, then bypass the actuator.

My $.02 Good luck

 

[Rickb1b]

Yes checked the power valves, they were cleaned during the top rebuild. However, you never know. I'll check them again and maybe try disconnecting them.

 

[guidoxpress]

is your exhaust valve solenoid even plugged in, or is the wiring broken..

the solenoid opens at 6800rpms...so if your hitting a "wall" i would check..

--solenoid itself
--wiring for solenoid
--exhaust valves for cleaniness, free movement in housing
--see if ALL your exhaust valve hoses are OPEN and CLEAR...gunk can plug the lines (INCLUDING the drain hose)
--check your exhaust bellows (orange diaphrams)

report back after you confirm ALL of the above

 

[f15ejedi]

If you don't find anything trom what the guys mentioned, check the clutch. Had the same problem on another brand of sled. I put different (re-built) primary on and it ran like a raped ape.

 

[2poor]

X2 on the clutching. If the clutching hangs up will do the same thing. Dont forget you are riding a 06 with 4 injectors. If you try to hold it at that RPM you have a lean or rich spot. the exhaust valves on a 06 will cause a problem at 5000 so if you want to do a good check on them pull the spring and cap the line at the control valve. You will see by pulling the springs and caping the line the sled will jump right from the bottom end. You did not say anything about a light so that sounds like to me you are hitting the lovable sweet spot we all hate on a 4 injector set up. there is a few other post in here about it.

 

[Rickb1b]

Ok I've tried about everything I can think of relating to the valves.

I thoroughly cleaned them, and forced air and a wire through all the passages. they are spotless.

I replaced the orange diaphragms and the gaskets. Then I did quite a few test runs.

With everything hooked up it still bogs at 6-7K. Blocked the lines... still bogs. Took off the clutch, to make testing easier....still bogs.

Figued it might have something to do with the valve springs, so I took them out and it still bogs. Then I wired the valves so they would stay full open...still bogs.

It appears this thing does not like 6-7K no matter what the valves are doing and the only way to get it above 7K was to wire the valves open (although it still boggs and surges at 6-7K).

So, I figure it's not the clutch since it does it with the clutch off. I think I've tried everything I can think of to eliminate the valves. It must be fuel related or the ECU is causing this.

I'll keep at it.

BTW it pulls hard all the way up to 50 MPH and 6800 RPM, it just will not go past these. It's a great machine if I never try to go past 50 MPH.

 

[SixtySevenGT]

Did you check the VES Solenoid wiring ?

This was mentioned but never addressed.

I disconnected mine accidentally and it would not run over 6800 rpm ----

 

[Rickb1b]

Yes the wiring is all connected and there are no codes flashing.

 

[chunkysoup]

u ran it around 7000 rpms with the clutch off?

 

[guidoxpress]

do not run the motor above 3-4,000 rpms with the clutch off...that is VERY bad on the motor/crank...and can cause some serious damage..

i would check your fuel pressure....hooka gauge on the fuel rail, CLUTCH INSTALLED, rear of sled off ground and slowly work your way up on the throttle...not rapid..and see if the fuel psi props..


get back to us with status..i know we can get this figured out...

 

[Rickb1b]

Ok so I've been searching more about my problem and I start to think it may have something to do with the TPS. So I go out and get the parts and build the tester. Just for kicks I hook it up to the TPS while still on the machine. At Idle I get 4 volts and at wide open I get 5 volts. Now after viewing the video on setting the TPS these numbers seem really high.

Is there a difference between measuring these while still on the engine and pulling the throttle body and measuring it. Doesn't seem like there should be.

I'm reluctant to change this because it idles fine. Thoughts?

 

[IceCap]

I have a hard time understanding that your sled idles fine at 4.0 volts??

I had a 2.8 to 3.1 volt reading at idle and it would surge badly and not go into reverse.

Does your sled go into reverse?

I really think you have a fuel delivery problem.

 

[Rickb1b]

Yea the volts didn't seem right to me either so I tested again. This time I got 0.91 at idle and 4.0 at WOT.

I think you're right I have a fuel problem. Next step is the fuel pressure.

 

[guidoxpress]

i dont think you can properly test the TPS adjustment with the sled idling..

you need remove the throttle bodies and do it like the video shows...its VERY easy and takes a few mins after you get the bodies off..

do that anyways...its worth having it set correctly regardless if that is your issue or not..

 

[diamonddave]

You did not say anything about a light so that sounds like to me you are hitting the lovable sweet spot we all hate on a 4 injector set up. there is a few other post in here about it.

That must be related to running boost with the 4 injector set-up. Mine and the other 06 in my group run flawless. Spot on linear throttle response at ALL throttle openings and RPM's. I only wish my 09 800 had throttle response, runnability, etc. like my 06 900.

I'm wondering if he has the injectors' connectors hooked up incorrectly. Maybe they are criss-crossed, low speed hooked up to high speed, and vice versa. Won't throw a code either. It would be very easy to doo this. I make it a habit to mark these very well on 06's. No worries with the 05's

 

[Rickb1b]

Ok a little more trouble shooting. I hooked up the fuel pressure guage (mine only goes to 100 psi). It reads over 100 throughout the range, however when I hit the bog it drops a little, not much, down to just above 100 psi.

However while I was playing with this, I noticed when I accelerate at a moderate pace it bogs at 6800 RPM and will not go past this. But if I stop the throttle movement right before it bogs and very slowly move it up, it will actually continue to accelerate all the way to 8K.

So basically if I feather the throttle right at the spot where it bogs I can get it to continue to accelerate, but if I move the throttle past this point very much it stalls and drops back to 6-7K.

Intersting; leads me to think it may be something in the throttle system.


As far as the injectors go (at this point I'll try anything) I switched them around and it made no difference. I put thenm back as they are labled. It says upper PTO, Lower PTO, Upper Mag, Lower Mag. So I connected them to the corresponding upper and lower wires.

 

[2poor]

That must be related to running boost with the 4 injector set-up. Mine and the other 06 in my group run flawless. Spot on linear throttle response at ALL throttle openings and RPM's. I only wish my 09 800 had throttle response, runnability, etc. like my 06 900.

I'm wondering if he has the injectors' connectors hooked up incorrectly. Maybe they are criss-crossed, low speed hooked up to high speed, and vice versa. Won't throw a code either. It would be very easy to doo this. I make it a habit to mark these very well on 06's. No worries with the 05's

You are right any time you start modifying the 06 you start having that problem starts becoming more noticable. Most of the stock ones dont have a problem.


Have you done anything to the intake, added a controller anything or just rebuilt engine? It ran fine before you rebuilt it. Does it go into rev.? Had a friend that rebuilt his he could not get it to go over 6500 rpm and would not go in rev. any more. We pulled the fly wheel off and when he put it together the key came out and was not in the right timing. after we fixed that it ran like it use to. Not trying to send you on a goose chase just asking a few more questions.

 

[Rickb1b]

This wasn't a full rebuild, I just replaced the jugs and pistons. Nothing else was changed. It ran OK before but still had a slight hesitation, not as bad as now though.

 

[2poor]

Unplug your the safty switches on your handle bar and see what that will do. If the throttle handle switchs may be not working right so if you un plug them that will take them out of the system. make sure you have key switch hooked up to shut off.