What the **** is wrong with this 2007 M8

[BennyX]

https://youtu.be/FmecRxZzAg0

 

[0neoldfart]

How is it to start? Seems like you have a throttle body issue...

 

[BennyX]

Doesn’t start well when cold. What throttle body issue are you suggesting?

 

[killerrf]

Could build a throttle position sensor tester and check it to see how voltage is working thru the ranges but seems like it’s sucking air in from crank seals or somewhere and running lean possibly? Maybe injector leaky.

 

[BennyX]

Engine holds 15psi for 5 mins
Injectors have been sonic cleaned and flow tested
compression is good

 

[killerrf]

Try making a throttle position sensor tester with 9v battery and u can see what voltages are at all throttle positions. U will have to get a resistor and step down to 5v.
Butterflies returning all
the way back to closed position?

 

[JMCX]

What is the thing with LEDs above the handlbar? Is that EGT reading in °C or F?

 

[BennyX]

Hi JMCX
Thats a dobeck fuel controller. It’s been removed from the circuit without change.
Digitron is *F

 

[0neoldfart]

I’m thinking either the throttle body shaft bushings are toast (causing an air leak), intake boots are cracked maybe. Maybe reeds are shot. To check for an air leak, spray carb cleaner around crank seals, intake boots, and throttle body linkage. Change in speed will tell you where to look closer...

 

[BennyX]

Reeds were replaced. Intake and throttle bodies have been doused in ether with no change in rpm.

 

[Mike270412]

Try making a throttle position sensor tester with 9v battery and u can see what voltages are at all throttle positions. U will have to get a resistor and step down to 5v.
Butterflies returning all
the way back to closed position?

Butterflies?

 

[Mike270412]

Had similar symptoms with a 600 and there was a kink or something binding in throttle cable. Butterflies were barely open enough to notice but sure made it run funny.

 

[mountianguy]

Reeds were replaced. Intake and throttle bodies have been doused in ether with no change in rpm.

Have you checked your fuel pressure? If you can find a different ECM to try could be it. If you have a good multi meter check the throttle position sensor just use ohms open and close slowly and watch the meter it should be going up and down nice and smooth. Its not the ideal way but its will get you an indication if things aren't right. I would inspect the wiring harness closely for any damage also.

 

[talon932]

What is your fuel pressure

 

[BennyX]

Delete

 

[BennyX]

Had similar symptoms with a 600 and there was a kink or something binding in throttle cable. Butterflies were barely open enough to notice but sure made it run funny.

And it ran all strange? This thing is possessed. Been through 3 mechanics and an arctic cat dealer

 

[BennyX]

What is your fuel pressure

Tried adjusting from 35 psi to 45 psi. Currently at 42psi

 

[BennyX]

Have you checked your fuel pressure? If you can find a different ECM to try could be it. If you have a good multi meter check the throttle position sensor just use ohms open and close slowly and watch the meter it should be going up and down nice and smooth. Its not the ideal way but its will get you an indication if things aren't right. I would inspect the wiring harness closely for any damage also.

Fuel pressure 42psi
changed ecu already

 

[JMCX]

Are the throttle blades tight on the shafts? Are the throttle blades synchronized? Is there something wrong in the coupling between the throttle shafts letting one or both of them float around at idle? If you're brave enough to put it on the snow is it actually rideable once underway?

 

[orange1]

My vote says throttle plates are open for some reason!...more than desired for idle, return spring broken at the tip? and ecm is seeing a request for fueling above idle, and the throttle safety switch is trying to do it’s job by dropping spark to one cylinder, could possibly test by unplugging the TSS( the switch in the throttle block pivot pin) if the motor takes off and doesn’t stutter but revs out more I would say that throttle plates are in fact staying open, or you have a combination of an air leak and a leaking injector?doubtful! Very similar to having a short cable, can you see if the lower throttle linkage is returning to the stop?