[08Bruteon30's]

i have a 08 750i that has lost all the low end power and is backfiring through the tb on the rear cylinder. it will not go over 32 mph and the 4x4 light is blinking from 2wd to 4wd but im sure the actuator is out on the front end because it still turns all 4 when it is in 2wd.


could the rear cylinder not be firing but every now and then and making it run like that. it will not idle either.

 

[phreebsd]

yep 1 cylinder runs like that.
wont idle and runs REAL rough

what all have you recently done to the bike? Try reseating the connections on the CDI and ECU? (2 biggest black boxes under the seat)
what rate is the 4x4 flashing. i would assume 1/2 second deom 2x4 to 4x4 of 1 second from 4x4 to 4x4..?

 

[08Bruteon30's]

looks to be 1/2 second apart. as far as the quad it has a hl 2" lift and 30" mudlites with a clutch kit, snorked and rad relocated. ill have to check the cdi connections and the plugs. would this also make it not run over 32mph? this all started after it was swamped. motor was gutted and cleaned thouroghly but hasnt run right since and has gotten progressivly worse.

 

[websy]

Im nowhere close to being an expert but my brute flashes like that when I have the other plug(not the belt switch) disconnected on the CV cover. And it runs like its in limp mode. Just a thought.

Check your fuses.

 

[08Bruteon30's]

well i was wondering if it was a "limp mode" deal but would that cut an entire cylinder off or just decrease a rev limit. basically all of my power and torque are cut in half right now and it backfires through the throttle body on the rearward side.

 

[websy]

I just read up in the manual. If your Engine brake Actuator fails your bike will flash 2wd/4wd and will not run at full capacity. Depending on how long the intervals between flashes are it could be 3 things. Make sure the actuator plug is tight and check the engine brake actuator fuse. It will be a 10 amp fuse.

Just a side note here..........there is a lot of information in the service manual which is available to download here once you become a subscribing member. Its worth the small amount of money even if you just download the manual. Trust me.

 

[08Bruteon30's]

thanks i will check all those things as well. hopefully i can get all this worked out. only going 32mph doesnt bother me but not having the torque to climb out of a neck deep mudhole is scary lol

 

[Kurly]

No expert here, but mine did almost the same thing when I fouled a spark plug. It spit and spat, no torque and would only go about 30MPH

 

[KMKjr]

When my engine brake failed, nothing happened. Bike worked fine but would not shift in/out of 4wd.

Had these symptoms twice.

First time : Belt frayed, tripped belt light, would only go 10MPH. Reset light and worked fine until belt tripped light again.

Second time : Small CDI plug was not fully connected. (came loose after servcing (can't remember what)) and would only go 30 mph with no acceleration, power, etc... Plugged it back in and never had problem again.

 

[08Bruteon30's]

ok thanks guys i havent had a chance to tinker with it but hopefully i will figure this thing out