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mpi eabc boost bacwards

madsledder

Extreme
Joined
Apr 30, 2006
Messages
122
Location
Creston B.C.
Country
Canada
Snowmobile
Yamaha
Bought sled new last year at the end of the season. 2015 viper mtx 190 Yamaha acc turbo kit installed by dealer. Not a lot of snow to play with last year so now that I'm riding this is what ive noticed. Boost seems to be high at 2000' 7psi was more I dropped it. And lowers as I go up in altitude 5psi at 6000'. Also it seems to run crappy after it is warmed up and sits for a bit. After I run it for a bit it clears up maybe 1/2 km down the raod. Temps outside were cold probably -10. I have looked and all plumbing seems to be ok.
 

I have removed the eabc and solenoid and will go out maybe tomorrow. Could a faulty map senser cause this? Solenoid seems fine. So question is eabc or map senser?
 
All my stuff is on its way back to me. But every thing tested good. Hopefully it was just a poor conection. He did mention that some have a flash in the ecu that keeps the #1 injector on. Any body know about this? Going to find out if they flashed the sled before I picked it up.
 
Well still having the issue. All the electronics were tested and ok. I found a boost leak and it is fixed. Still can not figure out why it is boosting too much at low altitude and not boosting enough at high altitude. Will run 8 psi at 2000' and 5 psi at 5700'. MPI has no idea why they are trying to figure out as well. But any other suggestions would be great.
 
Just in case any one is wandering or for future reference. It was the map sensor. A little annoyed because did this from new and mpi said no warranty on map sensor.
 
Well after riding in sicamous it is still building more boost at lower elevations than high. 1500' on the trail up to eagles and it would pull 7-8 psi and stay there but at the cabin 6000' 5-6psi. So back to try and figure out why it is doing this. At least its not running 11psi down low any more. Going to run it without the eabc hooked up and see how it runs.
 
Just to post what I've found. It is not a problem with the eabc. The problem is from the turbo not being able to build boost at altitude not sure why yet. Not boost leak, and not leak in the header. Turbo is sent to mpi but not sure if they are going to warranty anything yet. He said it looks like the impeller has rubbed the housing. I hope so, it's been like this since new.
 
Not sure what happened but seems to be working. They checked and pulled it apart(not sure how far) inspected. All was fine, ran on another sled worked perfectly. Got it back installed and it all seems to be working fine now. Lots of turbo chatter up high now like its supposed to. Now I have to redo clutching over revs a bit on take off up high and down low. Try it again at a bit higher altitude with longer pulls know for sure.
 


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