Backfiring on 850r turbo

[Gearhead#01]

Having backfiring issue on a 2023 Lynx Shredder RE. It will backfire on hard pulls at 7800 to 8000 rpm. It will not do it on holeshots out of the hole or when on and off the throttle hard. Just long pulls or 200 or 300 feet wide open into the start of a pull. This is what I have tried up to this point is
- change spark plugs ( yes indexed)
- checked fuel pressure, holds 43 to 44 psi at wide open across the field.
- installed new reeds.
- hooked to buds no faults at anytime recorded
- reflashed fuel injectors to ecu
- checked boost tube on the pipe, no breaks and no restrictions.
- new belt
- new rave valve servo motor

none of these have fix the problem. Some days it will barely do it maybe once in a ride. Other days does it just about ever time on long wide open runs. Sometimes once at 200 to 300 feet backfire and then backfire again at a 1/4 mile or so at still wide open.
I’m starting to think it is a fuel injector but not sure it it’s a main injector or a boost injector.
Anyone else have these problems?
And yes sled is stock. Except for a Sled Head Racing clutch kit that it ran perfectly fine with the whole last season with no backfiring.

 

[Gearhead#01]

Not sure if I said but it is a 850r turbo. Need some new ideas on this problem.

 

[dooman77]

click down on your clutch your hitting rev limitture

 

[turboless terry]

You are over revving. Drop you r's before you wreck your reeds.

 

[caper11]

You are over revving. Drop you r's before you wreck your reeds.

I kinda wonder if they are done already reading his post saying it was fine last season.

All it takes is a good backfire from cycling the throttle when overreving.

 

[Gearhead#01]

Yes I was testing it again today and noticed the turbo noises very loud at times when on and off the throttle at slow speeds. I’m at 1700 feet elevation and it’s making turbo noise like as if it was at 6000 or 8000 feet. Making to much boost I believe. Then sometimes sounds the same as it did last year. Much quieter. I also noticed that when it back fired today on long wide open runs the rpm would drop to 7600 ever 7500 then shortly after it backfired. So I have changed the waste gate actuator and hope to try again tomorrow. Fingers crossed.

 

[farmboy84]

I agree with others it sounds like over revving. Try clicking down or adding pivot bolt weight and see if it makes a difference.

 

[F_ast]

I'd guess your over revving... Maybe fuel issue? What fuel are you running? Usually polaris is more picky on fuel type, but we seen some funny things happen on old fuel.

 

[F_ast]

I did actually have a bad rave valve actuator last year on my 24. Come to think of it, it had no check engine light but did register failure to open/ failure to close codes on buds, and it would backfire sporadically.

 

[turbo800]

Like everyone has stated, its over-revving. Click down to load the motor more.
Also, the ECU may not like the rate of acceleration before you even hit Wide Open / Full RPM.
I would tear into it and see if the backfires have already broke the reed petals!

 

[Gearhead#01]

FIXED!! Problem was the waste gate actuator motor. Install new one and test with 2 rides now and backfiring is gone. Not an over reving issue. Waste gate will momentarily fail and close for a moment and cause excessive pressure and backfire would happen. Something to look for if anyone else is experiencing backfiring issues at 7400 to 7800 rpm. And it will not show any fault codes on buds as well.

 

[Driver]

FIXED!! Problem was the waste gate actuator motor. Install new one and test with 2 rides now and backfiring is gone. Not an over reving issue. Waste gate will momentarily fail and close for a moment and cause excessive pressure and backfire would happen. Something to look for if anyone else is experiencing backfiring issues at 7400 to 7800 rpm. And it will not show any fault codes on buds as well.

Lots of rave and waste gate actuators have failed on turbos and non turbos, its a common issue (same part for both). Thank you sharing the solution too.

 

[caper11]

If you are overboosting at a lower elevation you are overreving