Sled hits 7200, and acts like hitting Rev Limiter

[Ace Freely]

2015, with 1200 miles. Been running great, and then will top out at 7200, and pop like hittinf rev limiter. Put on new belt (First one on this sled) and douched out primary (2 arms were sticky, but still swinging out.)

Any thoughts?

Ace

 

[islanddoo]

I would change the plugs out! Have had a similar problem.

 

[Ace Freely]

DUH!!! WHY didn't think of that! Haven't had to change a plug since 2013! I was thinking reeds, but hope is just the plugs!

Thank you!


...any other thoughts?

Ace

 

[H20SKE]

Rider error.....

 

[Chadly]

Have you ever had the fuel regulator checked out?

 

[Ox]

...any other thoughts?

Ace

As above - fuel pump and any filters that may be inline, but I had an old Mx470 that would hit a wall too. It was certainly electrical, but it ran fine for what we needed, so I didn't chase it much. But that hit the same wall on the stand. I don't know if there is anything in a modern spark system that could "float" or not?

Easiest way to check - would be to put your machine on the stand (or a chum to pick the back end up - that you trust) and rev it up. Does it go past 72 or not? If it does, then it is fuel delivery most likely.


.

 

[jvb]

My sled did exact same thing. Rave position sensor

 

[Ace Freely]

While changing plugs, I saw that 3 y pipe bolts were gone. Plugs were black and oily. Hoping that replacing bolts and new plugs will fix it.

Ace

 

[jvb]

I saw my check engine light come on but didn't stay on. Was easy to diagnose that way as it was stored. But it did exactly the same thing.

 

[Goinboardin]

7200, I think, is the point that RAVE valves are supposed to go full open. So if you're still having trouble after fresh plugs and y-pipe bolts, I'd put the sled on a stand, with rave cover off, and rev it out. See if valves go full open or not. If no, check vacuum lines to valves. If those are ok, pull valves and clean then retest. If they do open all the way, and it goes to normal peak rpm, I'd suspect fuel pressure drops off when under load (as suggested above). Check fuel pressure regulator, in the tank (they pop out, just reseat, add 1/4" washers to the hold down screws). While on the subject of fuel system, change fuel filter (the external filter). I forget the part number but there are non Doo fuel filters for like $5 that work great, just need 2 fuel injection hose clamps to replace the factory crimp clamps.

Edit: for others' future reference, also check the aluminum RAVE nuts. They could have come lose, so valves don't open completely.

 

[Ace Freely]

If plugs and bolts don't work, it goes to the dealer!


Ace

 

[Goinboardin]

Oh, I suppose a 2015 is still under warranty. Good call then. Best of luck.

 

[TreeThrasher]

Rave position sensor failed. It has now lost track of rave position and has locked you in limp home mode and set a hard rev limit at somewhere just over 7k. Seems fairly common on the 15s, mine did it a couple weeks ago. And it will likely have set a p1477, 1478 or 1479 code but won't have an active engine code.

 

[800PowerFanatic]

Had this problem last week. No codes only happened in lots of snow under load. I burped the cooling system and problem went away....
heat soak maybe? Could have been a total coincidence that a rave problem disappeared at the same time, but whenever I've had rave problems the engine light would turn on. This is on my 13 etec turbo

 

[pyxle]

One of three things:

1 - As stated above, fuel pressure regulator popped out, causing low fuel pressure and poor running.
2 - Rave valves not reaching correct position (according to the ECM) which is usually NOT caused by the rave sensor, but the rave sensor just reporting the error. The RAVE check valve manifold (mounted between the reed cages of the two cylinders) is usually at fault. Not able to build correct pressure/vacuum to operate RAVE valves, THEN triggers the RAVE fault.
3 - Oil pump feedback wire. This usually triggers low operating RPM caused by going in to "Warm-Up Mode"

or it is just a spark plug....

 

[TreeThrasher]

With all due respect, the rave position sensor is creating this issue. If its a rev limiter at 7200ish it needs a position sensor. Period.

Plug it in to the budds and move the valves by hand. It's not going to measure a voltage change on rave function. No code will be thrown. It's the only scenario I have found so far that sets a hard rev limit with no engine light on

 

[Goinboardin]

^^ Good to know. Fuel pressure issues wouldn't be so cut & dry at 7200rpm I wouldn't think. ECU cutting timing to hold 7200rpm in response to a sensor fault makes sense.

Ace, please post up the solution when the time comes. Thanks.

 

[frog]

With all due respect, the rave position sensor is creating this issue. If its a rev limiter at 7200ish it needs a position sensor. Period.

Plug it in to the budds and move the valves by hand. It's not going to measure a voltage change on rave function. No code will be thrown. It's the only scenario I have found so far that sets a hard rev limit with no engine light on

Sometimes you can get a engine lite at low rpm's and budds will give fault coed for valves not closing which will be same thing. We have been able to reset percentage values for valve position with good luck but sometimes sensor just needs to be replaced. Make sure valve position is checked at closed, neutral and all the way open. Good luck.

 

[TreeThrasher]

Sometimes you can get a engine lite at low rpm's and budds will give fault coed for valves not closing which will be same thing. We have been able to reset percentage values for valve position with good luck but sometimes sensor just needs to be replaced. Make sure valve position is checked at closed, neutral and all the way open. Good luck.

Yessir but when it sets hard rev limit the sensor has failed. There will be no values to set on the Budds when it happens. I chased the issue for two days until we finally figured it out.
Did not throw a light so I assumed fuel pressure issue or some other glitch. Was rave sensor failure.