[michaelh427]

I have a 2007 gsxr 1000 only running on 3 cylinders. Brand new plugs, did resistance check on all 4 coils and everything is in spec.

Weird thing is is when I swap coils from cylinder 2 (dead cylinder) to cylinder 3 the problem doesn't move. I have spark in the cylinder and when i pull the injectors from the throttle bodies and try to fire the injector on 2 cylinder is spraying fuel also.

Cant figure out what would be my next step from here, any help would be greatly appreciated.

 

[BROTHER-N-LAW]

If you're getting fuel and spark, then do a leakdown. You must not have any compression, due to valves or rings.

 

[crazybill]

no codes ?

 

[Mr.Grey]

Check all your vacuum lines that are on the back of the throttle bodies. One for each cylinder, I had one off one time and it felt like the bike was only running on 3. Did you check fuel and spark by grounding the spark plug while its in the cool pack? Also make sure your fuel line isn't kinking when letting the tank down.

Sometimes it feels like its running on 3 when there's a vacuum leak or fuel shortage

 

[michaelh427]

What's a good psi to shoot for on this compression test?

Yes I grounded out the plug when I tested for spark on all cylinders and all spark plugs are sparking. I also pulled the fuel rail off the yhrottl bodies to see if I had fuel on turn over which I do.

No vacuum lines unplugged, that was my first go to.

 

[BROTHER-N-LAW]

Leakdown test would be better, but if you only have a compression tester, then just make sure that all cylinders pump to the psi. Usually between 180-220.

 

[michaelh427]

210 psi at all 4 cylinders, now I'm officially stumped

 

[suzuski]

Powercomander?

 

[BROTHER-N-LAW]

If you have a power commander, that might be the problem. Disconnect it to see if that's the problem. If not, then pull the side fairings and start the bike for about 30 seconds, then touch each pipe to see if they are all hot. Be careful not to hold your fingers on there and get burned. If one is cold then you know which one, and then try to change that injector. It may not be getting enough fuel.

 

[michaelh427]

Already disconnected the power commander and I've verified that number two isn't firing by disconnecting the injector and seeing no change in idle where as number 1,3,4 kill the motorcycle.

 

[horsinaround]

Did you try swapping out #2 injector with one of the other good holes to confirm the injector is good ? I would assume the ecm controls ground to fire the injector. Did you check to make sure you are getting battery voltage to the injector ? I would probly check voltage next and if that's good swap the injector if it was me.

 

[michaelh427]

Yeah I've swapped the injectors to every other cylinder and it just stays on cylinder 2

 

[horsinaround]

I would check voltage next and resistance of control wire from ecm to injector and probably run thru my ecm powers and grounds also.

 

[horsinaround]

How did the problem start ? Just randomly start skipping one day ?

 

[michaelh427]

Yeah, just shortly after I changed the fuel pump.

 

[504boy]

its the black box mounted to the throttle boddy on the right side of your bike i forget the name of it was told best out is to replace throttle boddies with a new set instead of trying to replace the box it was something about it being a b**** 2 sync..

 

[GSXXXR750]

Did you have this problem before or after you changed out the spark plugs

 

[michaelh427]

Before the spark plus change

 

[Ironman050284]

Did you ever figure out the problem? Having the same issue

 

[dany1000]

I have seen this issue on some gsxr and the ones I fixed was the connector itself not being tight anymore,replace and check
Also do continuity test with you dmm to check for open lines.
One of the cases was a faulty ECU,replace and done

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