'05 King Cat. Okay, it's not the servo motor, or the ECU...

John · Feb 8, 2008

Got the guy at the shop scratching his head too. At first I thought it was just a cooling system issue, didn't realize it was flashing 6 times repeatedly. On my last ride I figured that out, took it to the shop so they could confirm servo motor and it checked out good. No signal from ECU to motor so I cringe and tell them to get the ECU ($1300) on the way ($165 for next day service) only to get a call informing me that wasn't the problem. The tech tells me that he has checked all electrical components and they check out good. No grounded wires, good ECU, good servo, good sensors. Still not cycling the servo...

Any ideas on what to check next?

00buck · Feb 8, 2008

Save yourself the head ache and go to the exhaust powered valves.

Mainer · Feb 8, 2008

these are what 00buck is talking about if u decide to go that route.

http://www.supremetoolinc.com/index.php?page=products

BEPM7 · Feb 8, 2008

Do you know if those gas powered valves work on an M7 with a 800 big bore (can you just put spacers in like I have now?)

diggerdown · Feb 8, 2008

Have they checked the implus signal to the ecu? If it does'nt know the engine is turnig R's it won't send volts to the servo.

The pressure run valves are a better way to go.

Rixster · Feb 8, 2008

The red blue wire under the oil tank. Mine was rubbed through on 2 spots. I looked at those wires 3 times before I saw the rubbed spots. take your time and look VERY carefully. That is the power wire from the voltage regulator to the cpu for the servo motor.

blackt · Feb 9, 2008

I'm having this problem with my M7 as well. Same thing checked out servo motro, good, just had ecu reflashed so it can't be that. Dealer siad that where I hooked my egt's into is the circuit that runs the tailight, tach and servo motor. Any draw of more than 4 amps over normal and the ecu recognizes it as a ground or short and it flashes and goes into limp mode. I just fixed mine last night, tapped into my handwarmers for power for my egts, that circuit runs right off the stator and ecu doesn't recognize spikes or drops on that circuit. Haven't tried it out yet too cold but cross my fingers thatts all that was wrong.Let me know if you come up with something else.

crashnbash · Feb 9, 2008

I'm sure this was already checked, but if the power valve cables are not adjusted properly, or the valves are sticky, the servo motor will sense it and will not operate.

Spud · Feb 9, 2008

AC has an 900 issue...

replace the wiring harness, 900's have an issue with these. In time you will be burning out ECU's and servo motors, believe me.

John · Feb 11, 2008

$580 later and...

Picked it up from the shop on Friday. They found that the thumb warmer switch was shorting. Okay, great, lets unplug that sucker and try it. Servo cycles and I load it up. Get up to unload Saturday and the tach and headlight are not working. Open the hood and start looking, everything looks good. Screw it, I'm going anyhow. A mile up the road and I get the tach and light back, cool. Ride for a few hours with no problems, get stuck about 200 yards from my buddy who is also stuck. Got my sled out of the 4' trench (damn, that thing is heavy) and put on the snowshoes. I pack down a launch-pad and give er' the wood. Get another 25' and into limp mode she goes. Chit, stuck again. Radio my buddy and tell him he is on his own, get that sucker out and come help me get mine turned down hill. We get the last little climb heading back to the truck done (just kept it pinned or it would start limping again) and stop for a beverage. While we are sitting there I pull the plug on the servo to see what happens, fire it up and get the limp mode. I shut it down and plug it back in. We finish our beverages and fire up to head down. Thing runs like a champ, no limp mode, all the way back. I hate intermitant electrical problems.

The only thing that I have messed with, electrical wise, is the hand warmers and that was way before this started. No EGT, no rubbed wires, impulse to ECU is good, cables are in spec & valves are squeeky clean.

I'm going to hit all the connectors with some dielectric grease tonight. If that doesn't do it I guess I'll be spending the $100 on a new harness.

And yes, the Doo valves will go on as soon as I get this issue resolved.

kingcatmatt · Feb 11, 2008

Sorry I am kind of lost on this thread. So what is the issue with the servo. Is the sled running like crap... on 1 cylinder or what. I am having some issues with my king and it sounds kind of like what has been described in this thread. My is an 05 carbed.

John · Feb 11, 2008

Started out as a servo motor code/limp mode. Dealer diagnosed it as ECU. Got that and still have the problem. Not all the time though, just at the worst times...you know like after you drive 100 miles, the snow is great and it's still early.

76FOMOCO · Feb 11, 2008

just had the same with the head light and tail light, the problem was the wire to one of the hand warmer at the base of the handle bars was rubbing on 1 of the 4 clamp bolts that hold the bars in place so was a p i t azz to find due to the intermittent thing.:beer;

CatndHat · Feb 11, 2008

Plug cap, sometimes they get gooey inside, I have to clean mine twice a year!
Have to admit, it would be a cheap fix:beer;

Spud · Feb 11, 2008

we also had another 900 1M-efi that had a problem with a Handlebar heater wire and a King Cat also with a bad chassis harness that gave the same limp-6 flash code.
Good Luck John!

John · Feb 11, 2008

Good call

Rixster said:
The red blue wire under the oil tank. Mine was rubbed through on 2 spots. I looked at those wires 3 times before I saw the rubbed spots. take your time and look VERY carefully. That is the power wire from the voltage regulator to the cpu for the servo motor.

Well Rixster, I think you nailed it. Pulled off the oil tank and was sealing the connectors up and there it was, the yellow wire off of the regulator rubbed through. We'll see when I take it for a test towards the end of the week but I'm thinking you have a beverage or three coming if you ever get up this way.

Rixster · Feb 11, 2008

Good! Hope that fixes it for you!! I ended up burning 2 voltage regulators a stator and maybe a servo motor before I found the rubbed wire. Now I hope that the new servo motor I just installed fixes the rest of it. If not i am affraid it is me ECU, really hope not cause I cant go drop that kind o coin right now, could end my season.

This is out of the service manual, though it was interesting.

The APV system used on EFI models is very similar to
that found on carbureted models. The self-cleaning
and self-testing modes are much alike. The main difference
between the two is the higher total electrical
power required by the EFI and APV systems combined.
Because of these more demanding power
requirements, the EFI APV system gets power from
the stator lighting coil. The ECU constantly monitors
the power output of the lighting coil, and if the lighting
coil output gets too high or too low, the ECU will activate
the “limp-home” mode. The “limp-home” mode
is an ECU operated engine RPM limiter. When activated,
the “limp-home” mode will be seen as an immediate
loss of engine horsepower.
For example, if the headlight and taillight are disabled,
the ECU will sense a high voltage condition and activate
the “limp-home” mode. Adding more than 4 amps
of accessories will create a low voltage condition and
activate the “limp-home” mode.

John · Feb 12, 2008

"Limp home mode" eh? What they should call it is "Go home 1/4 mile at a time mode".
Good luck with yours. If you need the ECU I know my dealer has one for the EFI.
Thanks again, don't know that I'd have found it without your help and I know the service department wouldn't have before breaking me @ $60/hr.

John · Feb 22, 2008

Well the battle continues....

I think I have eliminated the voltage regulator and the servo motor. Woodys in Caldwell had both and was kind enough to let me try them both. I'm not sure what the specs say I should have at the regulator but I'm getting 11 ACV at idle and it drops as the Rs go up down to about 9. The new regulator did the same thing. Not sure what that means....
The problem is still there but I have discovered that if I start it up from cold and don't shut it off it works great. I unloaded it today and shut it off while everyone got ready, quarter mile from the truck and into limp it goes, servo code. Shut it down and wait 25 minutes...not long enough. Shut it down, pack the thing full of snow and wait 45-60 minutes and no problem. Every break I'd let it cool for a few and pack the engine in snow and wait at least 25 minutes and had no problems.

I have been through the harness 15 times and repaired two rubbed wires, pulled apart, cleaned and put fresh grease on every switch & connector. At this point I am ready to buy the ECU and try that. Big hit but I really don't think it is in the harness.

For example, if the headlight and taillight are disabled,
the ECU will sense a high voltage condition and activate
the “limp-home” mode. Adding more than 4 amps
of accessories will create a low voltage condition and
activate the “limp-home” mode.

This is interesting. I wonder if that means if I have my thumb warmer unhooked if it would cause it. Also makes me wonder if my Moose warmers are pulling too much juice. I have unpluged everything (one at a time) to eliminate them...This thing is sure turning into a love-hate relationship.

Rixster · Feb 22, 2008

My new servo motor fixed mine. So you have 11 volts at idle and it drops when the r's go up? mine is just the opposite, at idle I have around 7 volts when i bring the r's up even a little bit It jumps to 12 or 13 volts. I would say stator but, if the stator was bad it wouldnt work when cool like you are explaining. Where are you testing voltage?

'05 King Cat. Okay, it's not the servo motor, or the ECU...

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