Polaris RZR Forum - RZR Forums.net banner

1 - 20 of 36 Posts

·
Aspiring Perfectionist
Joined
·
4,685 Posts
Discussion Starter #1
Alright, guys... we've been chasing and fighting this code for over a month now on my buddies machine. There are a couple other threads on this issue that I've looked at extensively, and also buried myself in the service manual, but we've yet to solve the problem....

2018 XPT4
1400 miles
Stock tune, no engine, intake, or exhaust mods
Fuel pump replaced about a year ago at 800 miles with AEM pump

520344-17 code is Adaptive Fuel Correction - Too Lean

This code first showed up about 10 minutes into a ride about a month ago, we did some initial trouble shooting and found that whatever the hell came out of the gas pump he put into his RZR that day was horrid. We pumped it all out and it literally looked like red dye diesel. Symptoms that day were stumbling, limp mode, 520344-17 code, 65590/91/92 misfire codes, and blown fuel pump fuses (they would last about 10 minutes, the filter sock was so gunked up from the crap in the tank, that it was overworking the pump and blowing the fuse).

Fast forward to now, over the last month, we have completely pulled apart, cleaned, and ultimately replaced the entire fuel system piece by piece, everything was clogged up with gunk, rust, and just awful looking. Nothing has made any progress toward fixing the issue.

New AEM Fuel Pump
Pressure verified at 56 psi, also compared with my machine at 56 psi, both at prime, idle, and with increased RPM, Have not verified pressure under boost, but there is also no factory spec under boost, and the issue is present in a no boost situation, also, the machine hardly even runs enough to attempt to build boost

Fuel pump connections in the tank have been verified, internal hose replaced with submersible fuel injection line, and quality hose clamps, no signs of leaking fuel or loss of pressure form these connections.

Fuel tank has been completely drained and cleaned, twice.

Fuel tank vent, vent line, and fitting, have been removed, blown clean, and are flowing freely

No signs of leak from top of tank

Fuel pump nut and gasket have been replaced, pump hanger is aligned correctly and torqued to spec

Fuel lines show no signs of obstruction, fuel return line flows freely back into tank

Fuel rail and regulator have been replaced

Fuel injectors have been replaced, twice

Fuel Injector wiring is in good condition with no signs of fraying, loose, or broken connections

O2 sensor has been replaced

Spark plugs have been replaced, new plugs show a lean condition does exist, white haze after approx 10 miles of running

Battery has been disconnected for 24 hrs, cables touched together, charged, and verified in good condition

Spark arrestor has been removed and cleaned

No signs of exhaust or intake leaks

Belt has been replaced as well

Air filter is in good condition

Periodically during all of this, the machine will have brief periods where the code clears, and the machine will run fine for a short period, but the issue always returns after 10-15 minutes anytime after the code has been cleared, currently, the machine will run and drive ok at low rpm (below 4000) / throttle, but goes into limp mode at points, will fall flat on it's face if you try to increase the throttle, and this effect is also present if you free rev the machine in P or N. It will increase RPM with a slow, gradual increase in throttle, but just bog and drop RPM if you open the throttle past X point ( about 40-50% throttle )

We've pretty much eliminated any problem the bad gas could have caused, so at this point, I don't think we're chasing the effects of the bad gas anymore, or at least I don't know what else it could have caused, so I'm not sure if another issue has presented itself during the process, I don't know if said issue is an effect of the bad gas, I don't know that they are related, and I don't know if this is just an extremely freak occurrence of two unrelated problems developing at once.

I have read about the Throttle Body / TPS failing and being a rare, but possible cause of this code, to me, this would mean the throttle body isn't opening as the ECU thinks it should be, this is the next direction we are probably heading, but I wanted to post this up in case someone has any more insight or thoughts into what we haven't looked into, or what we should look into next. He's thinking of getting a programmer to be able to do some data logging and see if we can get some direction from the logs, and also re flash the ecu, but other than that, we're really at a loss as to where to head.

Anyone have any suggestions, thoughts, or ideas?
 

·
Premium Member
Joined
·
515 Posts
Wow, sounds like you covered the fuel system completely.
My only guesses, check compression and ecu. Can you flash it with your programmer?

It's a good mystery, I'll be interested in the outcome for sure.
 

·
Registered
Joined
·
556 Posts
Hmmm. If it’s lean, either too much air or not enough gas. Throttle position sensor?


Sent from my iPhone using Tapatalk
 

·
The Lone Rzr
Joined
·
2,282 Posts
With whatever that bad gas was it could have melted the cat?

"machine will run and drive ok at low rpm (below 4000) / throttle,
will fall flat on it's face if you try to increase the throttle,
and this effect is also present if you free rev the machine in P or N. It will increase RPM with a slow, gradual increase in throttle, but just bog and drop RPM if you open the throttle past X point ( about 40-50% throttle ) "
 

·
Registered
Joined
·
810 Posts
With whatever that bad gas was it could have melted the cat?

"machine will run and drive ok at low rpm (below 4000) / throttle,
will fall flat on it's face if you try to increase the throttle,
and this effect is also present if you free rev the machine in P or N. It will increase RPM with a slow, gradual increase in throttle, but just bog and drop RPM if you open the throttle past X point ( about 40-50% throttle ) "
My thoughts as well. Pull the muffler and looking at the honey comb condition would be a start
 

·
Registered
Joined
·
968 Posts
Check the harness/plug going into your electronic throttle body. The harness is held the to throttle body with a clip. Unclip that and wiggle the harness with the machine running and see if it causes the machine to rev and sputter randomly. Your symptoms sound similar to mine. Had to replace that pigtail a while back.
 

·
Premium Member
Joined
·
786 Posts
Have you swapped the ecu with another one ? I had a issue similar when I had my new desert car built and the only thing we could find was a ground lug that still had some powder coat on it, it would idle up to about 4K then fall off from there. Also Check voltage and make sure no issues there with a dead cell In the battery.
 

·
Registered
Joined
·
8 Posts
You could put a Wide band O2 sensor in the exhaust before the cat. You would have to weld in a bung. They do not cost that much 300.00 or so. They would tell you what the air/fuel ratio is.
 

·
Aspiring Perfectionist
Joined
·
4,685 Posts
Discussion Starter #12
@RWB713 any updates ?
Gutted cat, changed all 3 MAP sensors, verified MAP & TPS wiring, no progress

Going to swap my ECU in his machine & datalog at some point this weekend and do a more in depth check for intake / exhaust leaks
 

·
Premium Member
Joined
·
515 Posts
I was blessed with that code today in our '19 Xpt, along with the miss fire codes. Cruising along about 50 following cars. Kicked codes yesterday also so I blew out the clutches and scuffed the belt and sheaths. Actual code was 17 over 520344 over 3.
 

·
Premium Member
Joined
·
1,939 Posts
@White Lightning 19 So what did it do besides throw the code ...stumble , backfire ?
How many mile are on the RZR , What is your plan ...fuel pump?
The last number 3 , I believe means it has happened 3 times ...have you seen it before ?
 

·
Premium Member
Joined
·
515 Posts
@White Lightning 19 So what did it do besides throw the code ...stumble , backfire ?
How many mile are on the RZR , What is your plan ...fuel pump?
The last number 3 , I believe means it has happened 3 times ...have you seen it before ?
Not sure what the exact miles are, just under 2000. Has also thrown 65590,91,92.
My first thought is try the fuel pump o-ring.
Hoping someone on here would come with the cure. RWB had done a fuel pump on the one he's working on so although it didn't cure that one I figured it's good preventive maintenance at the least. Was about to do AA tunes but we decided to upgrade our pickup so the toy money is going to set it up for the 5th wheel so the tuner is on the back burner for now.

Something I've found as odd is it seems to kick the code when going along steady at about 40mph. I can pull over turn it off for couple seconds and and go with full response, and if I keep varying the speed it's just fine and check engine light goes off shortly. Hold a constant speed around 40 and seems to go to limp mode quick.
 

·
Registered
Joined
·
662 Posts
Screams of TPS to me. is it difficult/costly to replace? Is there a quality inline fuel filter In it anywhere?

It seems recurrent, even chronic, but not absolute. That should rule out the muffler, and you’d think valves too. almost has to be something electrical in the fuel/Ecu/sensor path

I was saw something like this twice In cars I’ve owned. Once was a TPS, and the other was a connector pin in the harness that had backed out and was making intermittent contact. That last one took a donor wiring harness to test with to find...
 

·
Premium Member
Joined
·
515 Posts
On reflection, that this has you stumped may be the most surprised I’ve been all month. guys in a world of shite....
Fact it has me baffled isn't surprising at all, fact that it's got RWB stumped is shocking. He's very knowledgeable on most models and common cures

Fortunately at this point it's more of an annoyance than a critical problem.
I have a new belt on the way and going to do the fuel pump o-ring and check the pre filter on the pump while it's out.
Fortunately this time of year we take our 800 as much as the xpt so I'm not shut down on getting to go play, and it does great on trails because there is no constant speed.
 

·
Premium Member
Joined
·
327 Posts
Based on everything you have replaced already and the code, to me it really sounds like a leak in the intake system. Probably intermittent when there is just enough vacuum to pull air through the seal or boot or whatever is leaking. Varying RPM may hide the problem because the computer is in constant recalculation when the throttle is opening and closing thus staying within tolerance for O2. You would obviously have to be at higher RPM to find it using the starting fluid/brake cleaner method. If you can pressurize the intake with compressed air and use the soapy water method, maybe that would find it.
This thread: Leaking intake boots on xpt
 
1 - 20 of 36 Posts
Top