you can check the compression but usually anything over 90 psi should be enough.
06' 900 mid throttle cutting out
- Thread starter biggsy90
- Start date
B
Tried multiple different plugs and no change.
compression is equal on both cylinders and 1 gauge reads 105 the other reads 90. I tested it after idling and prob close to 100 degrees. but then sits for a couple of minutes before i can get the plugs out and tester hooked up. so cools down some. Still just doesnt seem like a ring problem.
compression is equal on both cylinders and 1 gauge reads 105 the other reads 90. I tested it after idling and prob close to 100 degrees. but then sits for a couple of minutes before i can get the plugs out and tester hooked up. so cools down some. Still just doesnt seem like a ring problem.
So u did end up trying a new stator?
Did u attempt a different Ecu as well?
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Did u attempt a different Ecu as well?
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B
yep and yep. even tried to reflash the original computer. same problem. 2nd computer didnt change anything either. Im not smart enough to figure this out
S
does anyone know if you unplug the sensors on this snowmobile if the computer will resort to a preprogrammed value. On most car computers they do, so then you can when acting up unplug one sensor at a time and see if helps or not. If this was a car I would say your symptoms are a lot like an oxygen sensor. A cars computer will ignore oxygen sensor at WOT. Another thing if u do think it is running on one cylinder is temp gun the exhaust y-pipe at the jug and see if big temp difference, or one starts to cool down.
D
Have you checked you ignition coils?
A coil going bad can give the symptoms youre describing.
If a winding is broken the coil might work just fine when its cold. When it heats up and the coil expands slightly, the broken winding lose contact with its other end and the problem occurs.
Often primarily on lower revs.
On higher revs the power output to the coils is higher and that can help bridge the gap in the broken winding.
Easiest way to check it is to try another set of coils, if you have access to a pair.
Another quick and dirty way is to cover them in snow to cool them down once the problem occurs. Not a conclusive test but woth a shot...
A coil going bad can give the symptoms youre describing.
If a winding is broken the coil might work just fine when its cold. When it heats up and the coil expands slightly, the broken winding lose contact with its other end and the problem occurs.
Often primarily on lower revs.
On higher revs the power output to the coils is higher and that can help bridge the gap in the broken winding.
Easiest way to check it is to try another set of coils, if you have access to a pair.
Another quick and dirty way is to cover them in snow to cool them down once the problem occurs. Not a conclusive test but woth a shot...
B
Yep. Replaced coils as well. Still thinking injector wiring issue, but not real sure.
B
Going to pull the tank again tonight and check the wiring. At least I'm getting pretty fast at this part.
The way the problem has progressed seems like something is wearing out. started out very mild and has gotten to the point that it is not really rideable. I keep going back to the top end, but I would think that if it were a top end issue, WOT would still have problems. Any thoughts?
Won't be able to run it tonight, but hopefully if i find anything will run it tomorrow.
Could exhaust valves cause issues like this? I did replace the bellows and cleaned them and plugged the control valve ports. not sure what else to do.
The way the problem has progressed seems like something is wearing out. started out very mild and has gotten to the point that it is not really rideable. I keep going back to the top end, but I would think that if it were a top end issue, WOT would still have problems. Any thoughts?
Won't be able to run it tonight, but hopefully if i find anything will run it tomorrow.
Could exhaust valves cause issues like this? I did replace the bellows and cleaned them and plugged the control valve ports. not sure what else to do.
B
Checked all wiring tonight and seems to look OK. Ohm'd the injectors and they were all right around 12. Wiring from injectors to computer looked OK and basically no resistance. Checked compression again with different gauge and got 125-130 on each cylinder. so basically came up with nothing. Put the 2nd computer with SLP Flash back in just to see if it makes a difference.
too late to run tonight, but will try tomorrow, not very hopeful though. once it starts missing at idle will try to pull coil wires to isolate.
Think its possible that there is still a bad injector even though they were sent off to witch hunter?
too late to run tonight, but will try tomorrow, not very hopeful though. once it starts missing at idle will try to pull coil wires to isolate.
Think its possible that there is still a bad injector even though they were sent off to witch hunter?
I doubt the injector would be bad if witch hunter tested. IMO.
When u plugged the ex valves ports. Did u leave the ex valve solenoid in placed AND with the wiring harness connected?
I'm assuming when u looked at the injectors u verified there is no pin pushed inside when it's connected? This happened to me once and was hard to see. Same with Ecu harness except I had a pin actually come off the Ecu and was stuck inside the wiring harness plug.
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When u plugged the ex valves ports. Did u leave the ex valve solenoid in placed AND with the wiring harness connected?
I'm assuming when u looked at the injectors u verified there is no pin pushed inside when it's connected? This happened to me once and was hard to see. Same with Ecu harness except I had a pin actually come off the Ecu and was stuck inside the wiring harness plug.
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B
Exhaust valve solenoid is hooked up and still in place, just not working.
checked the connectors pretty well last night and everything looked good.
checked the connectors pretty well last night and everything looked good.
B
Fired it up tonight and did the same thing. After idling for about 5 min started dying on me. So SLP flash computer definitely does not change things. Pulled the PTO plug wire and immediately died (and shocked the crap out of me!) Then pulled the mag side and didnt change a thing. So its a mag side problem.
checked the compression last night cold to checked it again tonight and both sides are 120 warm.
checked the mag side coil for spark and bright blue and jumped over a 1" gap so i think the coil is fine. Which leads me to think that it has to be a fuel problem. 2 different computers, 3 different fuel filters, 2 different fuel pumps which leads me to believe that it is prob a injector problem. Talked to witch hunter and he said never say never, but hasnt ever seen an injector test good, but still be bad.
So, What am I missing? I think the logical next step is to get another injector, but not really looking forward to yanking the engine again.
checked the compression last night cold to checked it again tonight and both sides are 120 warm.
checked the mag side coil for spark and bright blue and jumped over a 1" gap so i think the coil is fine. Which leads me to think that it has to be a fuel problem. 2 different computers, 3 different fuel filters, 2 different fuel pumps which leads me to believe that it is prob a injector problem. Talked to witch hunter and he said never say never, but hasnt ever seen an injector test good, but still be bad.
So, What am I missing? I think the logical next step is to get another injector, but not really looking forward to yanking the engine again.
T
Well you have definitely narrowed it down in my opinion to either a fuel injector or wiring harness problem on the Mag side.
You've got good compression and good spark, the only thing that is left is fuel.
If you could find someone with the same sled I would try swapping out the harness between the ecu and the injectors. With witchunter testing the injectors, I would assume they are good, but the wiring harness might have broken wires inside the plastic sheething. Plus this would be a fix that doesn't involve pulling the motor out of the sled. Ohming the wires checks for continuity and will pass if the wire is only partially broken inside, but under load a partially broken wire will fail.
I replaced the injector on my sled, and it fixed my problem, even though the old injecor ohmed ok. But like you, I narrowed it down to a fuel problem on one particular cylinder. I guess at this point if I were you, I'd either replace the partial load injector or the wiring harness or both.
You've got good compression and good spark, the only thing that is left is fuel.
If you could find someone with the same sled I would try swapping out the harness between the ecu and the injectors. With witchunter testing the injectors, I would assume they are good, but the wiring harness might have broken wires inside the plastic sheething. Plus this would be a fix that doesn't involve pulling the motor out of the sled. Ohming the wires checks for continuity and will pass if the wire is only partially broken inside, but under load a partially broken wire will fail.
I replaced the injector on my sled, and it fixed my problem, even though the old injecor ohmed ok. But like you, I narrowed it down to a fuel problem on one particular cylinder. I guess at this point if I were you, I'd either replace the partial load injector or the wiring harness or both.
B
I think it would be unlikely to be the harness as its only 4"long, but stranger things have happened. Planning on getting the injectors, but may see if dustin has the harness as well.
Witch hunter does good work and checked and tested the injectors, but my theory is that when it heats up, something changes and he wouldnt have been able to catch this.
Last question, been doing some searching and I know its been discussed, but which injector is which again?
Witch hunter does good work and checked and tested the injectors, but my theory is that when it heats up, something changes and he wouldnt have been able to catch this.
Last question, been doing some searching and I know its been discussed, but which injector is which again?
The Bog
I had a 900 with the same issue, went thru everything you have.
I really believe if you have a Dealer with a digital wrench they should be able to tell you what it is.
I will tell you how I fixed mine.
The motor was a really nice one, the sled was a beater.
I bought a nice sled swapped the motors.
Sold the Beater sled with a stock motor in it.
Don't really know how it ran.
However when I put the good motor in the nice sled the problem went away.
I used -
Full Motor, fuel injector harness ECU Pipe Can.
Nice Sled -
The full wiring harness
VR, controls, TPS pigtail
Fuel Pump, regulator.
I removed the outlet fuel filter in the Tank
it was plugged.
What mine acted like it was too rich, and when it was cold that was fine.
Ran great at 6000+.
My motor swap sled still runs great.
I have a friend with basically a stock 05 900 having the same issue now.
He runs crap ethanol in it and loads it up with Stabil. I told him not too.
I need to figure his out too.
I had a 900 with the same issue, went thru everything you have.
I really believe if you have a Dealer with a digital wrench they should be able to tell you what it is.
I will tell you how I fixed mine.
The motor was a really nice one, the sled was a beater.
I bought a nice sled swapped the motors.
Sold the Beater sled with a stock motor in it.
Don't really know how it ran.
However when I put the good motor in the nice sled the problem went away.
I used -
Full Motor, fuel injector harness ECU Pipe Can.
Nice Sled -
The full wiring harness
VR, controls, TPS pigtail
Fuel Pump, regulator.
I removed the outlet fuel filter in the Tank
it was plugged.
What mine acted like it was too rich, and when it was cold that was fine.
Ran great at 6000+.
My motor swap sled still runs great.
I have a friend with basically a stock 05 900 having the same issue now.
He runs crap ethanol in it and loads it up with Stabil. I told him not too.
I need to figure his out too.
B
SOLVED, maybe
Well got the motor back in and changed the Mag side injectors and harness. Idles fine now! let it warm up to 130 and no problems. now just need to take it out, but just blew my knee out and having surgery next week. So wont be able to ride for a while.
TriumphoverU, I'm hoping you were right. Thanks to all of you for the help. Learned a lot about this thing.
Bill
Well got the motor back in and changed the Mag side injectors and harness. Idles fine now! let it warm up to 130 and no problems. now just need to take it out, but just blew my knee out and having surgery next week. So wont be able to ride for a while.
TriumphoverU, I'm hoping you were right. Thanks to all of you for the help. Learned a lot about this thing.
Bill
Don't Leave Us Hanging
Get someone else to ride it while u heal up.
I believe that is what fixed mine.
When I did the engine swap I installed a different injector wiring harness.
Smooth midrange ever since.
Get someone else to ride it while u heal up.
I believe that is what fixed mine.
When I did the engine swap I installed a different injector wiring harness.
Smooth midrange ever since.
B
Well, I was wrong. idles fine now, but cutting out is still exactly the sam. Not sure what else to do. I replaced the mag side injectors and not the PTO side. Guess I could try that, but they were sent to witchhunter as well, so dont think thats it.
for a recap, heres what I have done
reed valves
exhaust bellows
cleaned exhaust valves
New TPS and set it multiple times
new exhaust temp probe
used coils, condenser, regulator, stator, computer, air intake sensor
new fuel filter and used fuel pump
injectors cleaned by witch hunter
then replaced the Mag side injectors with used ones
indy dan TM1 bottom end
compression is 125 and equal
seems to run fine when cold then after about 10min the problem starts so makes it really hard to test it.
I must be missing something, just not sure what
for a recap, heres what I have done
reed valves
exhaust bellows
cleaned exhaust valves
New TPS and set it multiple times
new exhaust temp probe
used coils, condenser, regulator, stator, computer, air intake sensor
new fuel filter and used fuel pump
injectors cleaned by witch hunter
then replaced the Mag side injectors with used ones
indy dan TM1 bottom end
compression is 125 and equal
seems to run fine when cold then after about 10min the problem starts so makes it really hard to test it.
I must be missing something, just not sure what
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Exhaust "temp" sensor perhaps..they stick at a certain temp range and stay there!
Only way I found it was on " the wrench"
Only way I found it was on " the wrench"
