08 M8 help.

[Colten KM8]

hey, im new to the sport. i just bought a used 08 M8 off a buddy of mine. it has just over 1000km. i went for a ride today for about 4 hours. then this came on the speedo " ECU 21" with a little wrench beside it. whats that mean? thanks for the help!

 

[HiLlClImB911]

Knock sensor i do believe.

 

[belch22]

I think it is a knock sensor failure...could it possibly have had bad gas in it? or stale gas? Has the ECU been replaced? I think the ECU's were updated to take care of that code.

 

[Colten KM8]

there was farm fuel in it, low octane 83 or 85 if i remeber correctly. what should i do. is it ok to still ride it?

 

[Colten KM8]

also sometimes when i go for a ride, i kill the engine to take a break, about 3 or 5 seconds after the engine is off it backfires. only sometimes, is this normal?

 

[dezmitchell]

Thats what you get for buyin a sled off of shell......:d:d

The code your getting is indeed for the knock sensor....I would suspect your fuel, drain it then try new fuel the pre 10 m8's wernt to picky when it came to fuel but its the cheepest easiest place to start. As far as the backfire ....ive never encountered a m8 that does that so i dont know if it its normal ....that being said try to fix the knock sensor problem and hopefully the sled wont get a weird back fire thing goin on????

Is the sled at idle when your shutting it off???

One question for ya......On those CDI's there was a wire you could unplug and this would let you run prem fuel......All it does is advance your timing but this would screw with ya if its set to prem and your running reg fuel is this wire pluged in????

Wire pluged in = Reg fuel
Wire unpluged=Prem fuel

Personaly i run reg i tried to run prem with the wire unpluged but mine still seemed to run better on reg.

 

[mountianguy]

also sometimes when i go for a ride, i kill the engine to take a break, about 3 or 5 seconds after the engine is off it backfires. only sometimes, is this normal?

Just let it idle for a few seconds after a full throttle or hard pull and that should cure the backfire. This is a common thing.

 

[belch22]

Just let it idle for a few seconds after a full throttle or hard pull and that should cure the backfire. This is a common thing.

Mine would backfire too after I would run full throttle or a hard pull without idling for a bit....let 'er calm down for a little bit before hitting the kill switch.

 

[Colten KM8]

haha thanks Dez, ill try new fuel and see if that solves it. if not ill head over to Jeff lol. but thanks everyone for the help!

 

[slomo]

Thats what you get for buyin a sled off of shell......:d:d

The code your getting is indeed for the knock sensor....I would suspect your fuel, drain it then try new fuel the pre 10 m8's wernt to picky when it came to fuel but its the cheepest easiest place to start. As far as the backfire ....ive never encountered a m8 that does that so i dont know if it its normal ....that being said try to fix the knock sensor problem and hopefully the sled wont get a weird back fire thing goin on????

Is the sled at idle when your shutting it off???

One question for ya......On those CDI's there was a wire you could unplug and this would let you run prem fuel......All it does is advance your timing but this would screw with ya if its set to prem and your running reg fuel is this wire pluged in????

Wire pluged in = Reg fuel
Wire unpluged=Prem fuel

Personaly i run reg i tried to run prem with the wire unpluged but mine still seemed to run better on reg.

the wire you can unplug is for ethenol fuel enrichens the map by 3%