Lean Condition when running at/around full throttle

[Gmiller]

My 05 900 RMK runs awesome from idle to 3/4throttle, I rebuilt top end to 06 specs, reset tps setting and made sure there was no dead spots, Oil pump is brand new, brand new oil cable(not FBF but soon will be). Im running an SLP airbox, Sled has 1070miles. Because i rebuilt the top end i check the plugs alot to make sure im not running lean, im fine until im at and around full throttle, then i start to run lean, any suggestions as to why? I've been having the same problem since i rebuilt it?

Thanks for you help!
Grant Miller

 

[ghostwhite]

My 05 900 RMK runs awesome from idle to 3/4throttle, I rebuilt top end to 06 specs, reset tps setting and made sure there was no dead spots, Oil pump is brand new, brand new oil cable(not FBF but soon will be). Im running an SLP airbox, Sled has 1070miles. Because i rebuilt the top end i check the plugs alot to make sure im not running lean, im fine until im at and around full throttle, then i start to run lean, any suggestions as to why? I've been having the same problem since i rebuilt it?

Thanks for you help!
Grant Miller

Are your TB boots good? I would look real close for cracks or leaks. Check all your intake connections south of the air sensor.

Then start checking fuel stuff. Has your fuel filter been replaced lately? Might be getting plugged up. Your pump might be losing pressure or malfunctioning. I wouldn't think it would with low miles but they do go out from time to time.

 

[Gmiller]

Checked fuel pressure, 60PSI Cold. Throttle body boots are the new upgraded as of this fall. New fuel filter when i rebuilt engine. Thats why im at a loss, i've checked and double checked anything that would make it run lean!

Thanks Grant

 

[Gmiller]

ANYONE??? Im going riding this weekend???

 

[05900]

Is this based on plug color alone? As ghost said, you need fuel,spark,air why is it you are getting more air than fuel?
Is pickup in tank restricted? Pressure is not always volume.
Bad Injector ?
Slow/ bad exhaust probe?
Proper heat range plugs?
Improper/False Air.
Sounds like it may be easier to look at running conditions while hooked up to the "wrench" And see conditions at WOT.
Plugs may be getting "washed" at WOT and providide a false reading
What type of FUEL? ethanol etc?
Hope you let us know..and this keeps close to the top.

 

[Gmiller]

Im running 91octane, fuel pressures at 60 psi, exhaust probe is new, using oem spec for spark plugs, I'd go get it hooked up the the digital wrench but my dealer is in Breckenridge Colorado, they charge way to much just to hook it up, im not interested in paying 500 at this point. Oil cable is new and pumping oil, No one ever had this happen to them??

Thanks
Grant

 

[ghostwhite]

I would actually wonder if your pump is good. Someone here had said that they had a problem with their pump. It was fine at idle but wouldn't be able to keep up with the pressure demands at WOT

 

[guidoxpress]

does your ECU have anything other then a stock reflash?

did the sled ever have an SLP pipe, or does it have one now and no reflash?

 

[Gmiller]

Not 100% on it, but it has no reflash, it has an SLP airbox, no pipe never had one.

Thanks
Grant

 

[jaymzaugust]

Does the sled bog or lose power when you're at full throttle?

 

[Gmiller]

Nope no bog, Runs Great!