Need the M7 Experts on this one!

kraftymike · Apr 6, 2008

Can’t figure this out. Stock ’06 M7 EFI with 3600 miles never missed a beat till now. It is not flashing any codes but seems to be in limp mode. Start it up and it will run normal for 20 seconds and then fall on its face and start blubbering at about 6700 rpm. Turn it off and let it sit for a few minutes and it goes back to normal for 20 seconds and then on its face. I have unplugged and replugged every conector I can find without any luck. Is my ECU fried?

RACINSTATION · Apr 6, 2008

Any mods from stock? Have you checked your spark plug caps and your power valve cables?

BackCountryBasics · Apr 6, 2008

Do you have a buddy w/ a M7? Try switching ECU's w/ someone. That will eliminate the fried question. They are easy to swap out. Possibly a sensor or a short will do this also.

w8ing4snow · Apr 6, 2008

Is your throttle block loose? Heard of that problem with the thottle safety switch.

kraftymike · Apr 6, 2008

I will try a swap with a friend next time I ride that is a good idea. Only mod is a can that has been on there since day one. Plugs, wires and caps are all good. How do you check the power valve cables and what should I be looking for?

BackCountryBasics · Apr 6, 2008

Also, one more thing, I don't know if you know this (being so many miles, probably would have happened sooner if it was going to do it, I would think, but ya never know), but the tail light wires have been known to chauff & cause similiar problems you describe. Under the plastic tailight housing they run on the tunnel (06' had more issues than 07'). When the make contact the motor goes into fail safe mode & runs bad. Good luck, electrical gremlens are the worst!

Gvrunyn · Apr 6, 2008

A few things to check would be power valves if you have a track stand rev the motor to 7000 rpm and the powe valves will open. Another check to do is look at your pistons through the exhaust manifold when you take the pipe off . Look for broken piston skirts. A common problem might be internal coil which when motor warms up the coil will fail. I have heard of this happening on an f7 Do not plug in another ecu because this might wipe the program!

kraftymike · Apr 6, 2008

It started last weekend in Cooke in about 3 feet of heavy wet pow. I thought it might have been a water or icing issue, but it sat in a heated garage all week and was still the same today. I will start checking things one by one and hope for the best.

BackCountryBasics · Apr 6, 2008

Gvrunyn said:
A few things to check would be power valves if you have a track stand rev the motor to 7000 rpm and the powe valves will open. Another check to do is look at your pistons through the exhaust manifold when you take the pipe off . Look for broken piston skirts. A common problem might be internal coil which when motor warms up the coil will fail. I have heard of this happening on an f7 Do not plug in another ecu because this might wipe the program!

Could he maybe switch out coils first to check that like on the older poo edges I know that is the way they would trouble shoot that? Yeh, Coils will do that also kraftymike, good point Gvrunyn. We never had issues with anything like that on any of our M-series, & we put about 3000 miles on each sled a year (5 M's total), so that didn't come to mind. Sorry for not thinking of that.
My only experience with that are friends w/ the older POO's do it quite often I know & switching coils out was how they discovered bad coils.

kraftymike · Apr 6, 2008

I think my first step before I get too deep into it will be to put my ECU on my buddies sled and hopefuly rule out that problem. If it does turn out that my ECU is fried I can't hurt his sled by running it on there can I?

YNOT55124 · Apr 6, 2008

Plugs ...

Also had a gritty throttle cable once where it caused the Throttle Position Sensor to cut out.

BackCountryBasics · Apr 6, 2008

kraftymike said:
I think my first step before I get too deep into it will be to put my ECU on my buddies sled and hopefuly rule out that problem. If it does turn out that my ECU is fried I can't hurt his sled by running it on there can I?

No. If you put what you think is 'the bad' ECU on a 'Good' sled...all that can happen is it will make the 'good sled' run bad (like yours) if it IS in fact a BAD ECU.

minet · Apr 7, 2008

i had an f7 that did something like that once.
turned out to be a fuel pump. had a dealer take care of it for me at that time, but my bud was talking with one of the guys at bdx about it and they said it was common in that engine and an easy fix. so i might of got took by the dealer and they just purged it or reset it or somethin. sorry so vauge but it was a handful of years ago

bigbull · Apr 7, 2008

A stator going out will throw out symptoms like this. And on a 05-06 this is a A/C sled, so a bare wire shorting out as Mini stated will give this appearance. Eventually a bare wire like the tailight will take out an already fragile stator. Also, lastly, an overloaded stator will also cause abnomalies like this as well as underloaded ( like unhooking lights )
BB

AKboondocker · Apr 7, 2008

I put in some gas from some old cans recently that had some gunk in it that blocked the fuel pickeups in the tank. It ran great half the day, then barely ran at all when the fuel got used up some. It would idle fine, but bog out and die immediately when I tried to give her more gas. Looked into the tank and noticed little piles of crap floating around in the bottom edges of the tank. I drained and cleaned the tank, wiped the inside out real well, refilled it with fresh gas at the pump and the sled ripped. No problems afterwards. Hope thats your problem as you have the same symptoms and it was an easy fix.

Stack · Apr 7, 2008

Check the smart valves in the fuel tank, this exact thing happened to me on my sled. I only had like 500 miles or so on mine

kraftymike · Apr 7, 2008

Checked the pick ups in the tank all looks good there. I am thinking it has to be a ECU or sensor problem or maybe a coil. Thank you all for the help it has given my good direction and helped start an elimination process. This problem started on an exceptionaly wet snow day and noticed above normal amounts of water build up in my air box which is what I credited the whole problem to in the begining. Are any of the sensors in the air delivery system sensitive to moisture like I am describing?

Vern · Apr 7, 2008

a quick thing to check is to pull the plastic cover off and make sure the power valve cables are still attached to the servo. my buddies m7 was running just like yours is and thats what it turned out to be.

thump426er · Apr 7, 2008

My buddies 06 M7 did the same thing. Tried my ecu and still did it. Ended up taking it in to the dealer and it was the ecu and that the connection was the initial culprit. Was lucky the bad connection didn't fry mine. I promptly put dielectric grease all over my connections.

BC Green · Apr 7, 2008

KraftyMike, My 06 M7 just did the same thing with same mileage. I did everything these guys are telling you...process of elimination is good. In the end it was a chipped out corner of the reed pedel on the PTO side. The amount that was chipped out was small but it was the problem.

My symptoms were a bit more involved. Ran good for 20-30sec when cold then would bog. If I was able to get it reving and hold it there it would go good until I let off the throtle then it would bog again. Another sign was one plug looked good and the other was wet.

New stock reeds....and my sled never ran so good. Since then the same remady fixed my buddies 05 M7. He fought with his for half the winter.

Need the M7 Experts on this one!

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