'06 M7 cuts out @ 7000RPM below 6000'

m7ascent · Jan 29, 2012

Got an '06 M7 that cuts out @ 7000RPM below 6000'. Today the sled got unloaded at 5000 feet elevation and wouldn't pull more than 7000 RPM until it got up to about 6000 feet and then it opened up and ran great until it came back down below 6000 feet, where it started cutting out again. Seems to smoke a little bit when it's falling on it's face. Before today the problem was intermitent, would come and go, now seems constant at lower elevations. Has anyone ever had a computer flat out stop compensating for elevation? Is there another possible problem I'm not thinking of?

Baro tube is clean, Powervalves are clean, Powervalve cables are adjusted to spec., servo should be ruled out since it will in fact open up and run great.

mikew5945 · Jan 29, 2012

Lets start with the comment that pi$$es me off.
Sounds like clutching. What is your weights and pri/sec springs?
Are the springs broke? You sure?
It could be that you are not loading the engine with enough weight below 6,000'.

m7ascent · Jan 29, 2012

mikew5945 said:
Lets start with the comment that pi$$es me off.
Sounds like clutching. What is your weights and pri/sec springs?
Are the springs broke? You sure?
It could be that you are not loading the engine with enough weight below 6,000'.

Stock Primary, 68 gram weights, original yellow/white spring
Secondary has a new speedwerx black/yellow spring, had the same problem with the stock white spring.

I don't think it can be to light on weight, it ran proper RPM at these elevations before the problem started, if anything I think it is due for a new primary spring to get the RPM back up a tad because it has fallen to 7700/7800ish max when its running good (not cutting out). I don't believe the primary spring is broken, I checked it before the last ride, I will confirm nothing changed.

mikew5945 · Jan 29, 2012

m7ascent said:
Stock Primary, 68 gram weights, original yellow/white spring
Secondary has a new speedwerx black/yellow spring, had the same problem with the stock white spring.

I don't think it can be to light on weight, it ran proper RPM at these elevations before the problem started, if anything I think it is due for a new primary spring to get the RPM back up a tad because it has fallen to 7700/7800ish max when its running good (not cutting out). I don't believe the primary spring is broken, I checked it before the last ride, I will confirm nothing changed.

What elevation do you ride?
If you are running above 7,500' you should be maxing out at 7,800RPM with 68g weights. I was at 66g running 6-10,000'.
Have you ever gotten 8100 RPM out of it at your riding elevation?
I had the TT primary spring with the Cat green in the secondary.
Do you have any other MODs on it?

m7ascent · Jan 29, 2012

mikew5945 said:
What elevation do you ride?
If you are running above 7,500' you should be maxing out at 7,800RPM with 68g weights. I was at 66g running 6-10,000'.
Have you ever gotten 8100 RPM out of it at your riding elevation?
I had the TT primary spring with the Cat green in the secondary.
Do you have any other MODs on it?

We ride 5000'-8000'. RPMs run around 8000 maybe climb to 8100 on hard pack. I really don't feel like it's a clutching issue, like I said earlier, it craps out at 7000 RPM till we get it above 6000' and then it opens up and runs great. If it was heavy on weight it wouldn't crap out at lower elevation, it would be the opposite. Only mod is a SLP can and it has been on the sled since near new and has never caused a problem or bog at all. Next ride out we're taking the stock can to try just to rule that out, but I don't expect to find any change at all with it.

mikew5945 · Jan 29, 2012

m7ascent said:
We ride 5000'-8000'. RPMs run around 8000 maybe climb to 8100 on hard pack. I really don't feel like it's a clutching issue, like I said earlier, it craps out at 7000 RPM till we get it above 6000' and then it opens up and runs great. If it was heavy on weight it wouldn't crap out at lower elevation, it would be the opposite. Only mod is a SLP can and it has been on the sled since near new and has never caused a problem or bog at all. Next ride out we're taking the stock can to try just to rule that out, but I don't expect to find any change at all with it.

Lower elevation needs heavier weights.
When you are testing it reset your Max RPM's in the guage every time. You may be setting a limp mode by over reving at lower elevations. I don't know if the M7 had that feature.

dp2826 · Jan 30, 2012

Try a different belt?

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diggerdown · Jan 30, 2012

ecu could be failing and going full rich as soon as you get to a certain barimetric pressure.

Blk88GT · Jan 30, 2012

Power valves should be opening at ~6800rpm......

m7ascent · Jan 30, 2012

dp2826 said:
Try a different belt?

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Tried a new belt, no change, thanks though

m7ascent · Jan 30, 2012

diggerdown said:
ecu could be failing and going full rich as soon as you get to a certain barimetric pressure.

That sounds like it would cause this problem, how common of a problem is the ecu failing and going full rich at certain elevations? I've never heard of one doing that, not that that means anything. Next time out I'm going to try routing that tube up above the airbox where it will get fresh air just to make sure it's not sucking exhaust or something where it lays.

Anyone know if you can swap an '05 ecu onto this '06 sled if they are both square marked? I know the '05 was a fatter map, but I could eliminate that as the problem if it will work with the '06 injectors and such. I have an '05 for a back up sled.

m7ascent · Jan 30, 2012

Blk88GT said:
Power valves should be opening at ~6800rpm......

I realize that, and that was my first thought since it is close to that range when it cuts out, but it would have to mean that the servo is being elevation picky which I can't figure how it could be. I still need to confirm the servo is snapping open on the stand, and snapping open everytime. Problem is it's a riding friends sled so I am just trying to get as many ideas as possible on things to check that I may not have already for the next time we go riding.

mikew5945 · Jan 30, 2012

diggerdown said:
ecu could be failing and going full rich as soon as you get to a certain barimetric pressure.

It can't be pressure. If it is falling off at the same elevation every time air pressure will change with time during the day.
The Poo Pro has that problem. The ECU will learn the elevation pressure and other junk. It will bog when they all come together from an old problem.

m7ascent · Jan 31, 2012

mikew5945 said:
It can't be pressure. If it is falling off at the same elevation every time air pressure will change with time during the day.
The Poo Pro has that problem. The ECU will learn the elevation pressure and other junk. It will bog when they all come together from an old problem.

I can't speak for if it does it at this elevation everytime, just what was experienced last ride...unloaded at 5k, ran like chit till 6k, then ran mostly good above 6k (full throttle bog every now and again) till it came back down below 6k at the end of the day, then started running chitty again.

I did have a thought today about the Throttle Safety Switch, what are the symptoms of the TSS acting up...say the rider is putting side pressure to the throttle and the bushings are a bit wore?

Also, still wondering if it ok to swap the '05 Square ECU with the '06 to eliminate that.

yosh30 · Mar 24, 2012

ever get this figured out?

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