DET 1/8th to 1/4 throttle

RoostinRyan · Jan 21, 2018

For starters my sled is a 2012 800 rmk. Straightline performance pipe, ggb can, vforce3r, PAR 13.6 head, wiseco axys pistons, modded airbox, 62g weights, 3 to 6k feet. I've been having cut out issues which after doing some reading could be because I'm under weight in my primary and maybe it's hitting the Rev limiter. It's running right about 8250-8400 and when I run 64s I run too low of rpm at 7950-8000. First question is, do they make 10-63's? Today I was riding down the trail with the throttle barely cracked and I got det code and limp mode. This happened 3 times all of which were with the throttle barely cracked. Can too light of weight in the primary cause det problems even when not wot? If not, what are some things I should be looking for? I thought I had sorted this out a couple weeks ago by cleaning the power valve ports but seems to have come back with vengeance. I'm gonna go through it tomorrow and check the valves again but I have a hard time believing they are plugged again after 2 rides.

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Sheetmetalfab · Jan 21, 2018

ryanlinger said:
For starters my sled is a 2012 800 rmk. Straightline performance pipe, ggb can, vforce3r, PAR 13.6 head, wiseco axys pistons, modded airbox, 62g weights, 3 to 6k feet. I've been having cut out issues which after doing some reading could be because I'm under weight in my primary and maybe it's hitting the Rev limiter. It's running right about 8250-8400 and when I run 64s I run too low of rpm at 7950-8000. First question is, do they make 10-63's? Today I was riding down the trail with the throttle barely cracked and I got det code and limp mode. This happened 3 times all of which were with the throttle barely cracked. Can too light of weight in the primary cause det problems even when not wot? If not, what are some things I should be looking for? I thought I had sorted this out a couple weeks ago by cleaning the power valve ports but seems to have come back with vengeance. I'm gonna go through it tomorrow and check the valves again but I have a hard time believing they are plugged again after 2 rides.

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You are experiencing detonation.
These things are lean in the midrange stock.

Try ethanol mode on the trail. This will tell you if more fuel in that range will help.

With a pipe, head, airbox mods and such you really need better fuel and or more fuel in the low mid cruise speeds.

RoostinRyan · Jan 21, 2018

Sheetmetalfab said:
You are experiencing detonation.
These things are lean in the midrange stock.

Try ethanol mode on the trail. This will tell you if more fuel in that range will help.

With a pipe, head, airbox mods and such you really need better fuel and or more fuel in the low mid cruise speeds.

I guess I forgot to mention that I have a pcfc with the Slp stage 3 map. I'm also running 30 percent avgas. Sorry about that. At the beginning of the season running the same set up I was running 14.5 afr pretty much everywhere in the mid range and 12.5 wot. Now my afr is showing 12 to 16 mid range and 10.9 wot. I don't really trust the sensor as it seems to run the same as always except now with the cut out and Det. I feel like I would notice it running that rich if it really was. The only thing I've really changed is the weights from 64s to 62s.

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SRXSRULE · Jan 22, 2018

Just an FYI.... a bone stock 12/800 will pull 10-64's no problem at 3-6,000 ft.
With everything done to your sled if it had the correct fuel map in it should be pulling 66's or 68's.

RoostinRyan · Jan 22, 2018

SRXSRULE said:
Just an FYI.... a bone stock 12/800 will pull 10-64's no problem at 3-6,000 ft.
With everything done to your sled if it had the correct fuel map in it should be pulling 66's or 68's.

That's kinda what I thought too. It came stock with 62s and pulled 8250 no problem. I figured after all the mods I should be able to pull at least 66s. But even with the 64s I wouldn't pull 8250. I have a hard time pulling fuel when my plugs are prefectly tan. I feel like there is legitimately something wrong with it.

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BILTIT · Jan 22, 2018

Must be an issue of some sort. My 11 with similar upgrades will pull 69's at 2200ft and needs a touch more weight yet. I run 62's at 8-8500.

what is your clutching setup?

RoostinRyan · Jan 22, 2018

BILTIT said:
Must be an issue of some sort. My 11 with similar upgrades will pull 69's at 2200ft and needs a touch more weight yet. I run 62's at 8-8500.

what is your clutching setup?

I'm running 62s with new stock primary spring, black/purple secondary spring and this helix

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RoostinRyan · Jan 22, 2018

I'm also running 18/43 gears. After reading all these replies I wonder if my sled is over revving so fast and I'm not seeing it on the gauge.

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gtwitch · Jan 23, 2018

I have the Stage 3 SLP on my 11 and runs fine with 63 g lightnings with blue/pink and the above helix and black/ purple secondaryI if you have put a new fuel filter and checked pressure then start looking for loose pipe or can supports /springs and check the obvious and retorque the DET sensor. Have heard of something loose attached to engine ratteling maybe even motor mounts/torque stops could be setting a DET.
gtwitch in wyoming

RoostinRyan · Jan 23, 2018

gtwitch said:
I have the Stage 3 SLP on my 11 and runs fine with 63 g lightnings with blue/pink and the above helix and black/ purple secondaryI if you have put a new fuel filter and checked pressure then start looking for loose pipe or can supports /springs and check the obvious and retorque the DET sensor. Have heard of something loose attached to engine ratteling maybe even motor mounts/torque stops could be setting a DET.
gtwitch in wyoming

I did notice today that my pipe is vibrating on the over structure. Maybe that could be an issue. Thanks for the tip!

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RoostinRyan · Jan 25, 2018

Rode the sled today after putting 64g weights in. The cut out issue is resolved but still getting det limp mode while on the trail. Seems to go lean at 6500ish rpms and det. The only difference between now and when it ran good is the vforce reeds I installed at the beginning of the season. I'm thinking of adding fuel to the map in that range and seeing if it helps. I'm tempted to yank the reeds out, though, as it seems they have been a lot of problems.

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peaceofwork · Jan 26, 2018

More than a couple guys have removed their Vfarce reeds and been pretty happy about it, I wanted to like the ones I had but after time I bought boyesen replacements for the stock cages - for me it was a good move. I got a good steady predictable idle and a strong running machine again.

gtwitch · Jan 26, 2018

Likewise on the V-force I had no problems with V-force in my stage 3 setup on my 11 800 163 but I had a guy want the V force so I put in Boysen reeds on the stock cages and really noticed very little if any difference. All of my riding is above 9500 ft to 12000 ft.
gtwitch in wyoming

RoostinRyan · Jan 26, 2018

I added fuel to the 6k-7500 rpm range below 60 percent throttle. Gonna see if that solves it. Bringing my computer with me this weekend too. I'm pretty new to the tuning thing so I'm hoping I can figure it out. I tired of riding a sled that runs crappy. Im making progress though.

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RoostinRyan · Jan 26, 2018

peaceofwork said:
More than a couple guys have removed their Vfarce reeds and been pretty happy about it, I wanted to like the ones I had but after time I bought boyesen replacements for the stock cages - for me it was a good move. I got a good steady predictable idle and a strong running machine again.

This is basically the last chance I give them before pulling them. I want to like them too and have hard feelings about the whole thing as I wanted stock replacement reeds and was talked into buying vforce3r because I was told they fixed them.

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AKFULLTHROTTLE · Jan 26, 2018

I agree it needs more weight, how many miles on the sled and have you replaced motor mount rubbers? Could be why you cant pull the correct weight.

I have seen bad injectors also do this, and or fuel pump as well.

RoostinRyan · Jan 27, 2018

AKFULLTHROTTLE said:
I agree it needs more weight, how many miles on the sled and have you replaced motor mount rubbers? Could be why you cant pull the correct weight.

I have seen bad injectors also do this, and or fuel pump as well.

I have 3300 miles (2 seasons) on the sled. I bought it used with 300 miles. I haven't replaced the rubber mounts as they looked good and I haven't ever had an issue with belts. I might just change them out though. Wouldn't hurt. I'm pulling 64s now and could probably pull more. I don't know how long the ves ports have been plugged up but I'm attributing that to be the cause of not being able to pull 64s before

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diamonddave · Jan 27, 2018

ryanlinger said:
I'm also running 18/43 gears. After reading all these replies I wonder if my sled is over revving so fast and I'm not seeing it on the gauge.

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I would throw the 19 tooth in it. I run my wife's '12 with some of the stuff you have and 10-66 Bellybusters. You may need to load the motor even more than you are currently loading it.

13.6:1 at 3-6K feet is pushing it though.

The ECU's and Det sensor in these can get real sensitive with a fast rate of RPM climb. And there were a few of the early Pro's and Dragon's that were just too sensitive with aftermarket heads.

I wouldn't remove you VFR3's just yet.

RoostinRyan · Jan 27, 2018

diamonddave said:
I would throw the 19 tooth in it. I run my wife's '12 with some of the stuff you have and 10-66 Bellybusters. You may need to load the motor even more than you are currently loading it.

13.6:1 at 3-6K feet is pushing it though.

The ECU's and Det sensor in these can get real sensitive with a fast rate of RPM climb. And there were a few of the early Pro's and Dragon's that were just too sensitive with aftermarket heads.

I wouldn't remove you VFR3's just yet.

That could be very true. I found out that I've been using bunk gas too. I found out that the station I've been using has 21 percent ethanol in it. My tuner for my truck tells me. We just got a place to get good ethanol free so I'm gonna run that tomorrow mixed with my normal amount of avgas. It was making my truck run bad enough to make me check so I'm sure it was affecting the sled

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Scott · Jan 28, 2018

ryanlinger said:
I did notice today that my pipe is vibrating on the over structure. Maybe that could be an issue. Thanks for the tip!

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I can promise you that if your pipe is touching anything else it will hit the DET sensor.

As you stated in your first post, you bump the throttle going down the trail, you will have a vibration harmonic right at that spot where your pipe will bounce off of the bulkhead underneath. That sensor is very sensitive. It's a microphone basically. When your pipe bounces off the bulkhead it will send a vibration back in through the engine and I guarantee the sensor will pick it up.

Pull the pipe and see where it's vibrating and rubbing.

Make sure that the padded pedestal underneath the pipe is not worn out.

MAKE SURE YOUR MOTOR MOUNTS ARE FRESH.

DET 1/8th to 1/4 throttle

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