2009 Assault weird bog mid range

[Rockies rule]

I was out riding yesterday and my sled ran great all day. Then right at the end of the day I was cruising along and the sled started to bog when i hit the throttle. I shut her down right away and pulled the plugs and noticed that they looked great. I popped some new ones in and she fired right up and idled fine. I hopped on and it started to bog right away so i cracked her wide open and it cleared right up. After pulling the plugs again and having a really good look and letting it cool down I fired it back up and she ran great no bog at all until it warmed up. I noticed that the bog only starts to happen at exactly 104 degrees Fahrenheit. The hotter the sled gets the worse the bog. But no matter how hot it gets it still idles fine and clears up at full throttle. It almost sounds like it is only running on one cylinder when it happens.I am getting a blink code #7 which says it has something to do with the fuel injector circuits.

Also the sled has the fix kit, 2010 motor, a 155" track extension, a new clutch and an mbrp can.

What is stumping me is why is this heat related? does the fuel system change its injection cycles when the engine heats up? Any help would be great guys. Thanks a lot.

 

[diamonddave]

I was out riding yesterday and my sled ran great all day. Then right at the end of the day I was cruising along and the sled started to bog when i hit the throttle. I shut her down right away and pulled the plugs and noticed that they looked great. I popped some new ones in and she fired right up and idled fine. I hopped on and it started to bog right away so i cracked her wide open and it cleared right up. After pulling the plugs again and having a really good look and letting it cool down I fired it back up and she ran great no bog at all until it warmed up. I noticed that the bog only starts to happen at exactly 104 degrees Fahrenheit. The hotter the sled gets the worse the bog. But no matter how hot it gets it still idles fine and clears up at full throttle. It almost sounds like it is only running on one cylinder when it happens.I am getting a blink code #7 which says it has something to do with the fuel injector circuits.

Also the sled has the fix kit, 2010 motor, a 155" track extension, a new clutch and an mbrp can.

What is stumping me is why is this heat related? does the fuel system change its injection cycles when the engine heats up? Any help would be great guys. Thanks a lot.

Yes. The ECM changes the duty cycle of the fuel being injected based on input signals from the TPS, CTS, (coolant temp sensor) air temp sensor, barometer sensor. The helpful thing in your case is the Code 7 flash you are seeing. This is usually found to be a broken or chafed wire. If you have a digital ohm meter, you should be able to diagnois which injector circuit is compromised. Or you might be able to find it by digging into it.

 

[PaulAnd]

Check your fuel pump strainer/sump hoses while your at it. They will fill your tank with silicone slime and clogg filter and injectors. Not sure when second pair of injectors open but that could be why it runs ok full throttle, closed to half throttle would be upper injectors?

 

[volcano buster]

My CFI-4 600 was doing something similar to this yesterday. It was intermittent and hard to replicate. I was at St. Helens and could start up a good pull. I had about 1/2 tank of fuel but it would start to sound like it was cutting out and drop my rpm's down to about 7300-7500. Sometimes I could let off the throttle then get back on it to clear it up. Usually by then I would lose my momentum and would have to turn out. This happened several times during the afternoon, but on shorter blasts of the throttle there was no indication of an issue.

 

[Rockies rule]

Hey guys, sorry i havn't responded on this topic for some time but i have not even looked at my sled since april. I have been to busy camping and quadding. So today i figured i should have a look at the problem and see if i could figure it out. After a lot of checking and head scratching i finally found it! I have a bad fuel injector. It is the top one on the left. My fluke meter reads open when I test it. It is supposed to read 12 Ohms or something close to that. So I am super happy that I found the problem but when I phoned my dealer and they told me the price for one injector my jaw hit the floor! It was $250 Canadian for one. Now I am asking you guys if you know any good online places down in the usa to order OEM sled parts. I have bought a ton of stuff for my other toys down in the states for a lot cheaper then I can get them in Canada. so I a hoping that I can find an injector for a lot cheaper on the other side of the boarder. So thanks in advance for any info guys!!

Also the injector i need is again for a 2009 rmk assault and the injector is the yellow color code.

 

[slash]

Get a hold of freeagent she runs a parts dept in washington and can get you a better $$

 

[diamonddave]

Hey guys, sorry i havn't responded on this topic for some time but i have not even looked at my sled since april. I have been to busy camping and quadding. So today i figured i should have a look at the problem and see if i could figure it out. After a lot of checking and head scratching i finally found it! I have a bad fuel injector. It is the top one on the left. My fluke meter reads open when I test it. It is supposed to read 12 Ohms or something close to that. So I am super happy that I found the problem but when I phoned my dealer and they told me the price for one injector my jaw hit the floor! It was $250 Canadian for one. Now I am asking you guys if you know any good online places down in the usa to order OEM sled parts. I have bought a ton of stuff for my other toys down in the states for a lot cheaper then I can get them in Canada. so I a hoping that I can find an injector for a lot cheaper on the other side of the boarder. So thanks in advance for any info guys!!

Also the injector i need is again for a 2009 rmk assault and the injector is the yellow color code.

Nice work on the diagnosis. Before you order an injector, there is a little more testing you need to do. You are very close.

Were you backprobing the affected injector at the wire harness where it plugs into the ECM/ECU? Or have you removed the injector and tapped/backprobed directly into the wiring DIRECTLY AT the injector?

I would be very surprised if the injector failed electrically. I would bet that one of the 2 injector wires has chafed & rubbed through somewhere and is not making contact so it can't complete the circuit causing the check engine light to flash code 7 and making the injector not fire.

There have been a few reports (not many) of fuel injector wires chafing. I haven't seen, read, or heard of any injector electrical failures.


I would hate to see you purchase a new injector if a wire repair is all you need. If you determine that injector replacement is truly necessary, then try these guys for a replacement. I have used them for years in my automotive profession and sled repair and they have a perfect record for me.

http://www.docinjector.com/ I use the Federal Way, Washington store and the Renton, Washington store.

 

[AKSNOWRIDER]

You might also check your reeds, they will do the same thing when they shed a petal....

 

[Rockies rule]

Hey guys thanks a ton for the info and ideas! Yes I had started with the ECM connector and had the same thoughts of a broken wire. So I then looked for a bad wire and did not find one. so then i looked for the plug that will disconnect the injector from the harness. Low and behold some retard engineer at Polaris figured that the harness does not need plugs or connectors. I even read it in my service manual it says to replace injector cut the harness!! That blew me away that i should butcher my wiring harness! so to be sure that the injector was bad I probed the wires where they come out of the injector. It still read open. so i do what the manual says and remove the injector from the circuit and it still tested open. So I am pretty much positive that the injector is bad.

Thanks again diamonddave for the advice!!

 

[diamonddave]

Beautiful. Nice job on the diag. Surprised because injectors hardly ever fail electrically. Typically they will fail mechanically long before.
Give Dr Injector a call for an injector. Let us know what they say.

 

[Rockies rule]

Will do. I am out of town for a bit but i will call them when I get back.

 

[Rockies rule]

Hey guys sorry for taking so long with updating you on the situation. I installed the new injector today and also a new fuel filter while i was in the area. Put her all back together and primed the fuel system. Gave a couple pulls on the cord and away she went. I let it warm up and varied the throttle through all ranges. The sled runs great!! Now she is all ready to hit the slopes!

I am heading out for my first ride on sunday!!! cant wait! it will only be a road ride but it should scratch some of my sledding itch haha. There is about 2 to 3 feet in the mountains around my place!

 

[diamonddave]

Nice. did you get the injector from Polaris or somewhere else (aftermarket)??