[AllBlackWhip]

Just an update in here. The problem is that the secondary injectors do not give enough gasoline when used by the bike. The tests were fine however so the problem could lay in the ECU. Service stated this and they're going to try and remap it.

 

[TheGeek]

Still haven't seen a fuel volume measurement. This is classic fuel starvation.

 

[AllBlackWhip]

Still haven't seen a fuel volume measurement. This is classic fuel starvation.

Fuel flow was normal but volume was tested on dyno and it wasn't normal. The secondary injectors had all normal values in the injector test done by injector firm but the bike can't for some reason spray enough fuel from the secondary injectors. They said that if the remap doesn't work, they have to replace the secondary throttle body and its fuel lines/injectors all in one.

 

[BillV]

Anything is possible but unless someone who didn't know what they were doing was previously fiddling with the maps, this doesn't make a lot of sense.

Per 6-3 in the service manual, the EXCV moves to full open and full closed during powerup and you should be able to see that. Moving a little bit is not nearly enough. You could unplug the EXCVA and remove its pulley (careful, follow the service manual procedure). You'll then be able to turn the valve to full open and, to be sure, use some wire to keep it in that position. You'll get an C92 error but it should rev - if that's the problem. Reinstalling and adjusting the EXCV system is lengthy. See 6-6 to 6-14 in the service manual.

There's only one throttle body, not a primary and secondary. There's one fuel rail for all eight injectors. You seem to be getting a lot of faulty information.

 

[TheGeek]

Yeah, who told you the fuel flow was normal? If the injectors are working then only two things are possible. 1) not enough fuel being supplied. 2) the tune

1) it's super common and most shops make assumptions. replacing a throttle body, with good injectors because the injectors aren't spraying enough. That's the dumbest thing I've ever heard.

2) This is broken down further: A) there's an aftermarket controller on it like a powercommander. B) someone has tried to flash it.
a) is it even installed correctly? And has it been taken out to eliminate it as the source of the issue.
b) ECM flashes can go very bad. Do you know any history on this bike?


At this point, my best advice to you is to get the bike back from the shop and take it to a different shop. Since they're telling you it could be this or that, they don't know what the problem is. This is a sign of a bad shop. A good shop will do diagnostics and tell you what the problem is, not what it could be.

 

[AllBlackWhip]

@BillV was right. The EXCV was the problem and the bike has now full power. After 4 months of hair pulling it finally works. The bike was running with 2 cylinders before and took it to the service who changed its injectors which were broken. They also noted that the EXCV wires were disconnected (this was because I took off the exhaust and didn't yet assemble them back in) and plugged them back on. They misplaced them and the valve just moved a tiny bit, but not fully open. I even called to other Suzuki service guy about this and he noted that it does work even if it moves a little bit. Yes it moved a little bit, but got stuck after that.

It actually never gave any error lights for the EXCV and then the service removed it and reflashed the ECU and disabled the EXCV so it doesn't show up any error codes. It had to be adjusted because after that the idling RPM's rose to 4k but this guy knew what he is doing and now it runs 100% smooth and the gas cutting while riding on steady gas will no longer happen.
Thanks guys for help, it was really frustrating problem but this help made me understand things a little bit more. Also that you should not trust some services 100% 😅