2020 Supercharger wot bog/misfire

[bdcat162]

Have a 2020 supercharged 165 that runs great on low to mid but hesitates or misfires most of the time when sled is at wot for more than a few seconds. Checked spark plugs, checked that the power valves are within spec, exhaust springs are tight, y pipe is tight, no leaks there. However, there appears to be oil residue on top of air box where it connects to the throttle bodies. The springs that hold the airbox tight to the throttle body assembly are all in tact and they are tight but can see oil/fuel residue sitting on top of the air box where it connects. Residue is evenly coated on each side of the air box. It seems that there is a little blow by occurring at the air boxlike it is separating from the throttle bodies when wot. Would appreciate any help if someone has had a similar issue thanks!

 

[boondocker97]

Is this something that has gradually gotten worse or started happening all of a sudden? How many miles on the sled and how many miles on the kit?

I didn't do the install on mine, so I didn't get to see how all the parts go together, but if I was checking with those symptoms I'd try to figure out if it's a too much or too little fuel condition. Did you happen to shut it down and check the plugs right after it was acting up? If so were the plugs overly wet or dry looking?

Did you lift the rear end of the sled and watch to see if the powervalve servo is actually opening the valves when the engine revs up?

Any reason to suspect low compression in the engine?

I know you said plugs are good, but when I picked mine up I was told BR9EYA plugs gapped to 0.020" and change them every 500 miles.

 

[bdcat162]

Is this something that has gradually gotten worse or started happening all of a sudden? How many miles on the sled and how many miles on the kit?

I didn't do the install on mine, so I didn't get to see how all the parts go together, but if I was checking with those symptoms I'd try to figure out if it's a too much or too little fuel condition. Did you happen to shut it down and check the plugs right after it was acting up? If so were the plugs overly wet or dry looking?

Did you lift the rear end of the sled and watch to see if the powervalve servo is actually opening the valves when the engine revs up?

Any reason to suspect low compression in the engine?

I know you said plugs are good, but when I picked mine up I was told BR9EYA plugs gapped to 0.020" and change them every 500 miles.

I did check the plugs on the mountain this last week. They looked normal and double checked the gap specs which is like you said .018-.020. Made sure they were good. That being said I actually put a new set of correctly gapped BR9EYA's in before the last trip just to be sure. The original set of plugs that I put in at 50 miles (when sc kit was installed) seemed normal maybe a little rich if anything. Sled only has 175 miles. I have not lifted the sled up and checked if the servo was opening or not. I will do that next chance I get, thanks for mentioning that. I will also do a compression test. I have never had to test a ctec 800 what is optimal range to be looking for? And max difference between each cylinder? Thanks.

 

[bdcat162]

Is this something that has gradually gotten worse or started happening all of a sudden? How many miles on the sled and how many miles on the kit?

I didn't do the install on mine, so I didn't get to see how all the parts go together, but if I was checking with those symptoms I'd try to figure out if it's a too much or too little fuel condition. Did you happen to shut it down and check the plugs right after it was acting up? If so were the plugs overly wet or dry looking?

Did you lift the rear end of the sled and watch to see if the powervalve servo is actually opening the valves when the engine revs up?

Any reason to suspect low compression in the engine?

I know you said plugs are good, but when I picked mine up I was told BR9EYA plugs gapped to 0.020" and change them every 500 mi

Is this something that has gradually gotten worse or started happening all of a sudden? How many miles on the sled and how many miles on the kit?

I didn't do the install on mine, so I didn't get to see how all the parts go together, but if I was checking with those symptoms I'd try to figure out if it's a too much or too little fuel condition. Did you happen to shut it down and check the plugs right after it was acting up? If so were the plugs overly wet or dry looking?

Did you lift the rear end of the sled and watch to see if the powervalve servo is actually opening the valves when the engine revs up?

Any reason to suspect low compression in the engine?

I know you said plugs are good, but when I picked mine up I was told BR9EYA plugs gapped to 0.020" and change them every 500 miles.

Also forgot to mention that it hasn't gotten worse, I have only had it out on two trips totaling 125 miles on the kit and it has done it since the first trip out. The first trip out was in 3' of light powder and I told myself it was probably the sled bogging because of snow suffocating the intakes and never really thought anything more of it. After the last trip in marginal snow, it was still doing it and it caught my attention more so I decided to look into it more at this point.

 

[turboless terry]

Put new plugs in. Had turbos do the same thing. Looked fine but were bad

 

[bdcat162]

Put new plugs in. Had turbos do the same thing. Looked fine but were bad

I put new plugs in when I installed the kit and then again after the first 75 miles just in case. Put the new ones in before I went out riding last weekend just to be sure. When I pulled the new plugs out this last trip on the snow they looked good. I just noticed all the residue on the air box and around the throttle bodies after looking into it when I got it back to the shop. I thought maybe it was the exhaust springs if they broke or something. All the exhaust springs are doubled up and evenly set on the y pipe donut with no residue under the y pipe so that seems like it isnt pushing apart.

 

[spoon]

Sounds like fuel rich or maybe bad reeds? ECU flash not right? TPS switch?

 

[bdcat162]

Sounds like fuel rich or maybe bad reeds? ECU flash not right? TPS switch?

Thanks for checklist ideas, definitely worth looking into. The sled has a piggyback fuel controller, I am not sure how to check this besides sending it back and having them test it. I have never had to adjust the TPS so I will have to do some checking on that as well. Could bad reeds cause the sputter at just wot, or would it be noticeable when starting and idle too? I should have specified that it happens about 75% of the time when at wot, so I'm stumped. The sled runs really good otherwise, no bogs or lack of power on low to mid-range. There are a few springs holding the airbox/throttle bodies to the reed cages. It almost seems like they are separating just enough when at wot? Possibly causing some residue to spray around as well as losing some boost at full throttle when it sputters its pushing apart? Wish I was better at diagnosing that's for sure. Thanks again.

 

[boondocker97]

I've seen some guys report reed boots delaminating from the cages on late model ascender sleds. If that was going on and they are separating under higher boost it wouldn't be sending all the charge air through the engine.

 

[bdcat162]

I've seen some guys report reed boots delaminating from the cages on late model ascender sleds. If that was going on and they are separating under higher boost it wouldn't be sending all the charge air through the engine.

Thanks. I will probably get that taken apart and see if there's an issue. If there is, would you recommend v force reeds or replace with oem?

 

[boondocker97]

I can't say that I have a recommendation one way or the other. I'd ask speedwerx or Jason Nethercott what they recommend that's not going to need the fueling adjusted for them.