Engine miss/ bog '05 900 rmk

[kevinstetar]

I am fairly new to the forum and it blows my mind how great all you guys are! If my local dealer had this as a resource, maybe my sled would have been sent back fixed instead of the same troubles with a $800 price tag.
Here's the issue, fires up fine, then goes solely on the PTO cylinder. you can pull the boot off the plug on the mag side, no change. Has good spark, swapped coils from my bros '06 900, no change. Dealer changed fuel filter, throttle/oil cable. Claims he checked stator, fly wheel, reeds, fuel pump, compression, and TPS, and no codes came up. After it is warmed up, it will run like a top for five mins, then miss, bog and back fire. If I park it in the heated garage for a half hour, it will fire up fine and go like a raped date for another five mins. The Big thing I find, when I pull plugs, mag side is clean, and dry. PTO side is damp and dark. Where do I start?

Thanks in advance

 

[05900]

AAAhhh..Check fuel pressure and compression? Ya got spark... Wiggle the harness at the stator/tps look for chafing and cracks.
Did he test exhaust temp sensor?? Rec. basics first progress from there is usually quick.

 

[cpx1000]

check 2 things. #1 check and make sure your injector on that cylinder isn't sticking 2 ways to test are number one with a mechanics stethoscope put the prod on each injector they should sound nearly the same and there should be an audible clicking inside the injectors themselves,


#2 run it until it starts to have issues then quickly pop out the injector and see if it has any "leakage" ie dripping, etc.

if you have good spark on both cylinders and the timing is correct which it is because it does run good for awhile, the stator will generally be an all or nothing problem and will effect both cylinders, so if that is all in place and the compression is good it must be a fuel problem. if that cylinder is fuel fouling that means it either has too much fuel like a leaking injector would cause, or the fuel isn't being properly burned.

also check the porcelain on your spark plugs for cracks these will cause issues usually only when warm and/or under load conditions. ensure your plugs are the proper type and gap, and finally make sure your plug wire aren't leaking spark. worn plugs can easily cause a wire to fail. keep us posted

 

[kevinstetar]

Stator is good. Is there a way to pull injector without pulling engine?
Think i narrowed it to either injector or cpu. Plugs are new, swapped from side to side and same issue results.

 

[cpx1000]

im unsure of if you can without. ill look into that. what you can do though is swap injectors and see if the problem stays or changes cylinders based on that you can make a fairly informed guess that its the injector if it moves or the cpu if it stays

 

[kevinstetar]

When I apply 12V to the injector I hear it click, resistance is good @ 12 ohms. What I don't get is why is it not throwing a code...

 

[cpx1000]

all the click means is that the injectors are switching. they can still leak out even if they switch properly. that is very perplexing though why even with those issues there is no codes, have you checked the specific values for each coil? I wonder if it has spark but not sufficient spark. I apologize for the suppositions but its hard to do a lot more with this one without being there. have you checked for vacuum leaks at the throttle body mount boots, also have you checked for compression when its hot. check the reeds for cracks, wear, bent, broken etc. and finally do the exhaust valves operate correctly. I know its a lot but on a ghost of an issue like this the best thing to do is start and the beginning and being entirely thorough check everything

 

[kevinstetar]

Checked the reeds, intake boots, swapped coils with another sled that is running like a top, checked exhaust valves. My next step is going to be swap injectors from side to side, wgen its warm ill check compression again. Its a wild goose chase! Thanks for all the input! Keep it coming, sounds like u have a wealth of knowledge, would be a dream to have someone in my area with a head like yours. Thanks again. I'll keep ya posted.

 

[cpx1000]

thanks I really appreciate that! let me know the result of the warm compression test as well as the injector swap. if none of those things fix the issue I would next check for good continuity between the injector connectors and the correlating pins at the Computer. if there isn't continuity you have a connection/ wiring issue if you do then it may very well be the injector driver in the computer. a stock reflash may help but then again it may not in which case a new computer would be in place. you can find many good used ones on here under the swap meet forums.

 

[cpx1000]

also call your local dealer and give them the VIN number. have them check to make sure all the recalls have been performed on your sled. they can be elusive but if you push hard they will do them if they haven't been done. and because they are recalls they are free. they two im thinking of specifically are the fuel pump and tank harness. make certain those have been performed by an authorized Polaris dealer

 

[guidoxpress]

if an injector is sticking, go to the hardware store and get a pint of "Toluene" and add to a tank of fuel...also mix 1oz of oil PER gallon of fuel in the tank...this will act as a fuel cleaner and if your injector is clogged, it will fix it. promise..next would be getting your injectors cleaned/rebuilt but try this first.

next i would confirm the stator is good by ohming it out....you could have a bad gap on the sensor attached to the stator but reads the keys on the flywheel...there is 1 sensor for the injectors and one for the crankshaft positioning...the wire may be damaged, the gap from the sensor to flywheel maybe off or the sensor may be bad.

all other inputs above will help as well...keep up the work and i know we will nail it

 

[kevinstetar]

Hey! Thanks for the input! How do I go about ohming out the stator? Sounds easy enough but I would hate to miss a small step. Thanks guys, your help may keep the hair on my head! Going to dig deep on 'er in the middle of the week, fingers crossed it'll be ticking by the weekend.

 

[guidoxpress]

you would have to get an 05 service manual to test the stator..or someone can email you the pages...check the links in the stickies for lots of threads on testing..

just note...even when you OHM a stator, it may come back ok and infact its not...you actually need a very specialized tool to read them..but most times when they read bad, its bad...its when it reads good it screws with you, lol.

but in this case, your really focusing on the CPS and Injector sensors, but i would test the whole thing while your there.

put it this way about most dealers...before i was sent to korea last feb..(airforce), my local dealership sent ALL 05-06 polaris 700/900s that came into the shop to my house for me to fix...not saying im a know it all..but it shows you how much some dealers really dont "know" much more then the average guy..

just take the time to learn your sled, everything you can...we have built this forum to an amazing asset for all sledders...but mainly for the die hard do-it-yourself mechanic...eff paying some stranger to pretend to work on your baby

do work!! post back good luck!

 

[cpx1000]

good advice Guido. definitely get a manual. if you don't want to pay full retail for a hardcover manual. you can download one to your computer for $5-$10 from tradebit.com don't worry its perfectly legal lol. I get all my manuals for my machine and my customers machines from there. but if you don't have a manual it will make your life much more difficult not only do they contain system/operation descriptions which are useful, but they also contain wiring diagrams, flow charts, and all the specifications you will need to test just about any part on your sled

 

[Cerialsledder]

Save your money.... I have the pdf version of the service manual Here is the stator page for ya.

 

[kevinstetar]

A minor set back, broke a small nipple off the coolant bottle while taking the injector out, . Got the injectors swapped, just need the new bottle to fire it up to see what happens. Would like to double check the fuel pressure when the sled is running too, see what's going on there... Hope it's the inexpensive part, and easy/ quick fix. Cross my fingers I get to it soon! Thanks for the posts guys!

 

[sloan188]

While you are waiting you can drill it out, insert a small copper tube and 2-part expoy it all back together...will be stronger than the original...at least that way you can continue the troubleshooting.

I've fixed a couple that way and they've been running for 2 - 3 years with no issues.

 

[cpx1000]

good idea sloan... kevin just be sure that if you do this there aren't any leaks and your coolant levels stay up. if you have to "burp" the cooling system its a pain but park uphill or lift the front end and it makes it much easier. good luck. sometimes these things are a can of worms. you fix one thing and create 10 other issues haha

 

[kevinstetar]

Great idea guys, thanks for all of the tips! Even though the sled isn't hassle free, you guys are the best!

 

[kevinstetar]

So I got it back together today. Swapped injectors, checked all connections, Checked resistance in all wires, (they were good), fresh fuel and plugs, new belt. Fixed the coolant bottle with brass fitting and two part epoxy, ($10, awesome!). Ran it down the street so far, the real test will be tomorrow.