I'm north of Cincy up by KI, what's the name of the shop? Always good to have the info if needed.

 

So your exhaust cam jumped timing due to the chain tensioner?
After you had fixed the timing, but the code was still present with CEL on, was it still in limp mode?

 

So your exhaust cam jumped timing due to the chain tensioner?
After you had fixed the timing, but the code was still present with CEL on, was it still in limp mode?

Am I 100% certain it was caused by the tensioner, no I'm not but I did replace it just to be safe. I'm not sure what else could cause it though, like I said I'm not a master mechanic. It was definitely out of time though and it was easy to tell by looking at dash marks on the cam gears. Also once I got it to top dead center, the slots in the ends of the cams (pto side) did not line up so cam holding tool couldn't be used.

After the timing was corrected, the check engine light was still on and the code was still showing on the dash. It was still in limp mode until the code was cleared. Once cleared it was back to normal.

The two things that I did was replace the O2 sensor because that seemed to be the common issue for the code, still didn't didn't clear. The second was corrected the time.

Also I did forget to mention in the original post, I did contact Rocky Mountain Utv about the code issue the also and they said that bad valve lash code cause an exhaust to run rich.

 

So this is my experience with engine code 520344-15 which is exhaust running rich, in other words to much fuel in the exhaust. I have a 2019 XP Turbo. Now I'm by no means am I an expert mechanic or RZR specialist. I'm just a man that was trying to fix this by learning, also save money and possibly help others. As we all know these RZR's are expensive to buy, upgrade, maintain and repair. Dealers are out of control in my opinion when it comes to figuring out problems. My dealer told me what they wanted to do to diagnose the problem and wasn't even in line with what the service manual from Polaris says to do to diagnose this code. So I didn't want to waste my money with them. *Sidenote having an actual service manual from Polaris came in very handy, found a new one on eBay for $90. Definitely worth it if you want to learn and having the correct specs with "how to info". So I read posts on this site, that site, watched videos and spoke to numerous people. So there are many things that can ultimately cause this code to "pop up". Causes that I found: -Bad O2 sensor -Bad Tmap sensor -Clogged muffler/cat including spark arrestor -Valve lash aka out of time -Valve not closing/seating properly -Clogged intake/filter Now Bad fuel pumps, injectors, injector plugs, clogged fuel supply, bad rings and spark plugs (there are probably others) that can cause code 520334-17 which is exhaust running lean. So to my code and experience. Code came on and RZR went into limp mode. The RZR ran ok up to 40mph(speed capped),9k rpm and no smoke at all. Plus I wasn't smelling that "gas smell" from the exhaust. It idled just fine, started right up, no misfires or backfired. It seem to run like normal but with no power along with sluggish take off. So I have read many times that a code will clear when it's fix. If not run in low at 4k rpm for over 60 secs. If that didn't work disconnect the battery and ECU. First thing I changed to O2 sensor, didn't work. So I started checking things that didn't cost money. Removed air filter, disconnected the exhaust from the muffler/cat system. I removed the air filter and it straight piped to let it breath. No smoke at all came out, no "gas smell" plenty of pressure coming out of the pipe. Still the check engine light was there. Also checked the following: -Checked spark plugs, looked normal -Checked to make sure it had spark, had it -Checked fuel pressure psi, all with in specs 52@idle and 60@9k rpm -Checked injector plugs, wires/plugs were tight and didn't look "burnt" -Checked injectors the best I could. I don't have a flow tester but they were definitely spraying out constantly. Used a large glass jar just to watch for a couple of seconds, not perfect or ideal... It worked This next part is interesting. -Checked cylinder compression. They both were fairly equal in pressure. Now I have an analog gauge and not a digital one. The needle was showing around 135psi. -Now no where in the service manual could I find the correct PSI specs for reference. So searching the internet in multiple sources could I ever find actual information that Polaris provides. Now individual sources on the internet is all over what the correct PSI should actually be. -Both cylinders were equal in pressure so I used that info to rule out that the pistons and rings were bad. The chances of both cylinders losing pressure equally is very slim. Yes the only 100% to check is to remove and inspect, remember trying to save money here. *Sidenote I later learned that when doing a compression check that the throttle pedal has to be fully depressed while cranking. Exactly why I don't know, remember I'm not an expert but from my understanding has something to do with the ECU software. So that could be what caused my cylinder compression check to be low. So now this is where the service came in handy. Service manual says valve lash and valve seating could be a reason for low cylinder compression and could cause the engine exhaust to run rich(520355-15). Ok so now I decided to dive into the engine and check timing. There are videos out there that walk you through this process. I found this one from Rocky Mountain Utv to be very helpful:

It shows how to check valve lash/timing, check tappet clearances, replace tappers and adjust lash/timing. This video and having a service manual was a key for me. Many people out there say if your engine is out of lash/timng that your engine will run rough, hard to start, smoke and etc... I'm here to tell you that ISN'T 100% TRUE because mine was out of lash/time. It was not more than probably 1-3 teeth off. Remember I wasn't experiencing rough idle, wasn't hard to start or smoking. The dash marks on the cam gears did not line up. The exhaust cam was out(verified with info from service manual specifically cam lobe direction while having top dead center) and it was opening before it should have. Since it was opening just fractions before that precise moment that it's was supposed to was causing unburnt fuel to escape. Fuel leaving a cylinder is excess fuel in the exhaust that will be detected by an O2 sensor. Guess what? That's the exhaust being rich and code 520344-15 is exhaust running rich. So I my opinion with my experience, I'm pretty sure that's what caused it. Before I went into the engine, I researched what could cause the cam lash/timing to be off and it seems that timing chain tensioners are 99% the reason. So at this point I wanted one hand to replace if that was the case. Seems that Polaris has has issues with multiple designs over time, wasn't ordering one from them and started researching after market. I came across this video:

I called TPR Industry and spoke with Greg. I think he may be the owner but if he's not, he's definitely the man though! He was so helpful before and afterwards. I told him what I had going on with the code. He told me that it's possible it could be just out enough to cause my issue. He explained to me about how oem tensioners work and fail. So I decided to purchase the manual tensioner from TPR. Now I'm not getting anything by saying this, just giving credit when credit is due. That tensioner was so easy to install and to adjust. Back to the story. I got it back in lash/time, when the process step by step to correctly to ensure that I didn't do anything wrong to cause an engine failure. Turned the key on, code still there, shut it off and then back on. Still there so I ran it in low at 4k rpm over 60 seconds. Didn't go away, disconnected battery and unplugged the ECU. Waited 30mins also wanted a break from it. Reconnected battery and ECU. Time to fire it up and it's still there. Now the frustration is at an all time high. Went back to the internet. For some reason I happen to search for "Polaris parts dealer near me", well all the local Polaris dealers popped up but there was one that wasn't. It was a motorcycle/atv shop. It was after 7pm all the dealers where closed expect for them so I called. Just to see if they had any idea. I started off by asking what parts they carried for Polaris. Mike(owner) said I don't carry a lot for Polaris, he then asked me why I called him for parts. I said google says your a Polaris dealer. He explains to me that he is a Polaris certified warranty center, wait what? He explains to me that Polaris has warranty repair places to where dealerships maybe small in the area, lack of dealships and perform work that the dealships can't handle. So I told him what I had going on with the code 520344-15 and the timing being out and then corrected. He replied with out missing a beat, "that's an emissions code, 90% they won't self clear". I asked how much to clear and diagnose? $100 and I'll make sure we know what's going on before you leave. So off I went at 8pm at night, he was willing to stay open for me because heard my frustration in my voice. Got there laptop in hand he walking towards me. He cleared it, ran his program and we were done. It's running like a champ, he said whatever you did fixed the problem. Test drove it there and the power back. If you're close to Cincinnati let me know and I'll provide his information. He definitely knows what he's talking, you can tell by looking at him that he is a motorcross dude, graduated from motorcycle institute of technology. Was the original O2 sensor bad, I don't know but the timing was off a some without a doubt. New O2 sensor (cheap one of Amazon, again trying to save money), new timing chain tensioner from TPR Industry and adjusting valve lash/timing. Then it just needed cleared. So if you took the time to read and are having the code 520344-15, I do hope my experience helps you. Again I'm not expert or super mechanic, I'm just sharing my experience with that damn code that others of dealt with. Thanks

Could you please send me the info of the place in Cincinnati l. We have been to many shops and have not been able to solve issue. Sounds identical to your situation. Thanks again

 

It was posted just above.

Thunder Roads Powersports
8749 Jordan Rd. Cleves Ohio 45002
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thank you for sharing this, I am having the same issue on my 18 turbo. I also have the same chain tensioner.