Electrical problem, ECM??

[skidoogirl]

Off and on sled has been bogging, but almost positive it's clutching. Mostly bogs when climbing and hit a bump, or jumping. So it needs some clutch work. It's an 07 600 SDI.

Yesterday was something different. It was bogging constantly, sometimes every few seconds. Feathering the throttle, pinning it, nothing really got rid of it. It progressively got worse and I stopped for a few minutes. Started it up and it wouldn't run. Soon as I gave it a little throttle it bogged hard and wouldn't recover till I let off, would barely get enough rpms to move the sled. Shut it off a couple times and started again. Whether feathering the throttle or trying to pin it, it would bog hard enough I thought it died completely. But would recover when throttle returned to idle, but a low idle. The idle has been lower than normal the last couple rides, like 1500. Yesterday it was idling at 1000.

Took a while to get out of the hills, jerking, bogging and not catching till throttle let off. It also backfired a few times while riding it out. Get on groomed trail and I held it steady at about 20 mph and no bogging. As long as it was slow and I didn't move the throttle at all it was mostly fine. I really didn't think I'd get it home, couldn't be towed as our other sled burned down at the exact same time.

Changed the fuel filter a few weeks ago. Battery is 12.5 volts. I bumped the tach on a tree last week and broke the lens. But it worked just fine for the rest of that day, no problems. Yesterday the needle would stick when I shut it off, it would be off by about 3000, and then it worked fine for a few hours. It did switch to km and then back a time or two. I think that may be a separate issue as some moisture was getting into it and it could just be broken.

Reeds are good, raves are good, no blown fuses, pistons look good, plugs look good, no warning lights or beeps. Did a cold compression test- 116 both sides. Forgot the hot test, will do it later. Seems like a fuel issue, maybe injectors? Do I need to take it somewhere to get them tested? I'm a little stumped on what to do next as I can't really test the injectors...


Clutches are clean and in decent shape, I clean them often. I remembered that I'm pretty sure the first time it "died" and then recovered when the throttle was let off, the tach went off as well. Maybe a coil or volt. regulator? All the electrical connections look good, but I didn't check the plug wires going to the coil. Lifted the track this morning and ran it in the shop. No problems. Idling at about 1100 when cold, 1600 or 1700 when warm. Revving it up, no bogging, no missing, no nothing. Would a faulty coil be on an off like this? Or is it more likely a connection somewhere that I've missed, like the wires to the coil?

Felt like a fuel problem, but if the pump and injectors aren't getting power no fuel will be running. I'm confused as it's running fine today in the shop. Can't really test ride as our snow is gone at the house.

 

[skidoogirl]

The local doo mechanic is thinking it could be the ECM. He says sometimes when they go bad it won't show up till it heats up and gets warm and will continually get worse, maybe why it's running fine in the shop this morning. Anyone know anything about that?

 

[highlimits]

You said in your first post that it would idle at 1100 rpm when cold then go up to 1700 or so when it warmed up. Has it always been this way as that is the opposite my 1000 works. When its cold it will run at 2500rpm then once it warms up it drops to around 2100rpm.

I also have a 1500ohm resistor in my water temp sensor going to the ecu on a switch. I have had to use it when my temp sensor failed and kept turning on my over heat light. My Koso gauge said the sled was not running hot at all. To the point, when I tried to start the sled after I changed the sensor it would start then die 3 or 4 times before it stayed running and it idled really low. I had forgot to flip the switch back to the sensor and the ecu thought the sled was nice and warm already.

I know there are only a few sensors on these SDI motors maybe try checking them with a ohm tester. I did mine in a pot on the stove. Would eliminate them if they tested out okay, I even went so far as to put in a few switches with resistors. That way if it happens again I just flip the switch and by pass that sensor.

In the mach section of dootalk there is all the resistances at there given temp so easy to check.

Good luck

 

[skidoogirl]

It normally idles at about 1900 or so. The day this happened it was taching very low, like 1000.
Today in the shop it was idling around 1100 when first started. Let it warm up and the idle gets closer to normal, like 1700. I'm going to take it out tomorrow and ride, see if I can get those symptoms again. It won't do anything wrong running it in the shop. On this sled the engine light always comes on when a sensor is bad. But I will try testing the sensors and see if any come up bad anyway.

 

[Summit X]

my bet, the sensor in your exhaust... i've have 2 go, same sled.

last time it went, it was running fine, slowed down to a stop and went again and i could only reach 6000 rpm @ 50km/hr. somehow it then fixed its self and it ran good for about another hr, but then crapped out on me again. it is an electrical thing and it can go anytime.

do you run the stock suitcase in it or maybe an mbrp?

the thermometer will probably run you about $300 (cdn).

 

[skidoogirl]

I have a can on it. The exhaust sensor broke a couple years ago and the engine light came on. But I kept riding the sled for a couple weeks, it ran just fine till I got a new sensor. I think this is something else.

 

[skidoogirl]

I will check the fuel pressure and then I'm gonna go riding and see if I can get it to do anything wrong. One more thought here. My raves haven't been working correctly recently, maybe for the last month. I clean them often, at least every month as they get dirty quickly. If I pin it or am on or off the throttle quickly they work. If I gradually accelerate or decelerate, they often won't open, or sometimes won't close. It's worse on the trail as I'm not WOT like I would be in powder off trail. On the trail I have to pin it hard to get them to open, and the trails we ride aren't usually good enough to go that fast as my sled's a bit squirelly. Off trail they normally work cause it's either WOT or not, and the hard acceleration normally makes them work correctly.

Sooo, now I'm wondering if that's electrical as well. After cleaning them they would still do it, I couldn't figure out why. The bellows look good, no holes or cracks. I didn't pull them clear off cause then I'd have to re seal them, but they look good. No pinched hoses, cracked hoses or anything else wrong I can see. 12.5 volt battery doesn't seem low enough to do all of this, but maybe I'll try a new battery. I'll test it again after sitting all night.

 

[Summit X]

you are right, when mine has gone before my engine light did come on... but still sounds kinda like the same problem.

question about your can (not about your problem)... do you any fibreglass wrap around the pipe where the sensor is?? i chatted witha guy about it and he suggested it to me as the original location was inside the can where it had more insulation. and where it is now is in the pipe and so it doesn't hold the heat the same, and therefore won't react quite the same.

 

[highlimits]

I am not sure how the 600 exhaust works but I assume that it opens when the ecu decides you may be on to something with and ecu problem.

I do have another thought for you though, what if your TPS is not working correctly that would cause a bog and if you held the throttle in one spot long enough maybe off the dead spot it would run properly. Maybe because of a dead spot in the TPS when you punch it the machine is not getting enough fuel added. May also explain why it would run as long as you never moved the throttle much. I think the only thing that tells the exhaust valve to open is a little check valve, based on TPS and rpm from the ECU. I know I had my TPS reset on buds and now my exhaust valves open just a bit sooner, I also don't get big black streaks in the snow any more under WOT. On my sled if you just roll on the throttle the exhaust will not open till around 6200 rpm, but mash it to the bar and it opens sooner. Could also explain your rpm dropping at idle, maybe there is just moisture in the TPS, when it dries out in the shop it works. You can check the TPS with a ohm tester to I believe It might show a flat spot in it as the resistance should be nice and steady up or down.

I bet the ECU is not cheep to replace TPS might give you another option hope you figure it out before the snow is all gone. To bad you didn't have some doo-ner parts like say off hubbies sled?

 

[MoFoREVxp154]

Was the fuel filter ever changed before..?..

 

[skidoogirl]

Replaced fuel filter twice in the last few weeks.
Went riding alone today and messed with some stuff. Put a new battery on, no difference. Swapped relays around, no difference. Everything still works, but the tach is done. It works, shows correct mileage. But sometimes it shows correct rpm, sometimes it's a 1000 or more low. Sometimes when I shut it off it will stick at 3000 and use that as 0 when started. So it will idle at 4500 and bounce clear off the tach.
I'm pretty sure now it's hitting the rev limiter, but at different rpms. When the tach was correct it would hit it at between 7500 and 8000. When the tach was off either way, it would hit it anywhere from 6500 to 8000. If the tach was working right on, and I was gradual on the throttle till about 7800- 8000 it wouldn't hit it or bog or anything. Soon as I pushed it to the bars it would hit the limiter, though the rpms still showed low. If I pushed it to the bars quicker it hit the limiter much sooner, and would just bounce back and forth as long as I held it there.

Last weekend I could barely get 5000 and was barely enough to move the sled and ride it out. Maybe it was hitting the rev limiter very very low?? The tach was working at that time, at least close. Does the sled rely on the tach alone to engage the rev limiter? Seems like I have a faulty TPS as well. If it only relied on the tach, it wouldn't be hitting the limiter as low as 6500. It seems to make sense that the tach is bad (at least off and on), and the TPS either needs reset or is bad because it is engaging the rev limiter too soon, and at completely different rpms. Even during the same run without shutting the sled off. If the needle sticks when I shut the sled off, I can push it down and it will be correct the next time started up, and vice versa.

The dealers aren't that close, and are morons from every time I've dealt with them. Which is why I won't just haul it down unless completely necessary. Anyone have any experience with a faulty TPS? Does it always need replaced or maybe just reset? I'll be getting a new tach and then deal with the TPS, if that's actually the problem. Other than this and the clutch work I still need to do, the sled ran fine. Just no top end because it was constantly hitting the limiter.

 

[highlimits]

Rev limiter that low is kinda strange I wonder if you are actually getting a code and it is putting the sled in limp mode. It is possible that the tach is so messed up that the check engine light is not working but it is still going to limp mode. Once it starts to hit the rev limiter at 6500rpm if you unplug the DESS it should reset the current codes and might run good for a few minutes. I know with my 1000 I put resistors in all the plugs just to eliminate the sensors one at a time of course. The temp sensor, intake air sensor, if you have exhaust you could jump that one out as well. It was the only way I could find which sensor it was unless I took it to the dealer and payed them to do it on BUDDS. I finally tested the TPS by opening it real slow and watching the ohms it was nice and steady till about 1/3 throttle. At that point the ohms jumped way up then after a bit more throttle came way back down and were normal again. 1 dead spot in it so I had it changed, when they checked the codes was just a Erave code.

It is really easy for the dealer to plug in BUDDS and charge you big $$ for it I just wonder if they would find it if it never showed up on the scan. Resistor out what you can it will narrow it down that is for sure. Wish I could help more but I have not had a lot of electrical problems other then that with mine.

 

[skidoogirl]

Thanks. I did not test the TPS yet since it's kind of a pain to get to the way it's facing. If the new tach doesn't fix the problem tomorrow, I will have to go ahead and test it. I can't say positively that it's the rev limiter, but that's what it feels like. It's just so erratic that it's tough to really know what it's doing. I'll try a new tach tomorrow, fingers crossed that takes care of it. I'll see.