Turbo Pro DET

[jhillam]

Riding a tried and true Boondocker water2air cooled Pro 800 and hit DET for first time ever in 2 years/1200 miles. Conditions:
7000' elevation
0 degrees F (Christmas Break cold front in Idaho)
80 degree F coolant temp w/o thermostat, new ski scratchers down
Flat field with occasional powder
12 psi on controller
50/50 Sunoco 112 race gas and non ethanol pump gas
8400-8500 rpm on gauge
-3 degree timing key
Ethanol mode on MFD Guage
Fuel trim raised to 41 on Boondocker controller as precaution in cold heavy air

New ski scratchers gave me lowest coolant temps I've ever been able to obtain on this sled. Skid scratchers only without thermostat are 120+. Rode the trail from 6000' and sled was ripping like you'd expect with cold air, perfect fueling and 12 psi. When I got to the field I turned off trail and punched it when I hit some pow. DET immediately flashed for first time ever on this sled and sled went to limp mode. I shut it off and lowered boost and drove home.

What caused it? Is my coolant:engine temp too cold to ensure fuel vaporizes fully before spark, was cylinder pressure too high with good boost and cold dense air, or does hitting rev limiter cause a DET light and limp mode on these pro 800 motors?

 

[Boston Racing]

Your overrevving it. Add a couple grams and you be back to normal. If you see 8500 on the gauge you are most likely bouncing off the limiter tripping the det code.

 

[ak]

Yes hitting rev limiter causes det on the screen then limp mode.

All it takes is a little snow dust on the belt at those temps to make it over rev.

 

[kgra]

Agree with other guys 8500rpm is to much. Can also make sure the spark plugs havent loosened off.

 

[Spaarky]

When you say 120+. What are your temps typically? I believe it's 123, you start retarding timing. So if you were above that most of the time. Your sled was not running near its potential. Temps are down now. Your slamming the rev limiter.

You almost need to retune now that you are staying under the thresh hold.

 

[jhillam]

What is rev limit on stock ecu?

 

[RDS88]

You have to ask yourself, your sled ran flawless before you installed ski scratches. Seems like the ski scratches have created the problem.

 

[RobertTrivanovic]

Sounds like a rev limiter problem or maybe a bad batch of gas or maybe somethings is banging around under the hood thats causing it to trip the sensor? Im chasing a similar issue right now, think mine is a over revving issue but havnt had a chance to test the sled since adding weight