2000 busa light load surge

[Norvin]

99 and 2000 ecu's are the same......but, I've got a late 2000 plated busa thats actually a 2001 (has in tank pump different harness etc).
If your pump is outside then 2000 it is.

If you have no luck with ecus, I'd be willing to try your ecu in my 99, if that helps.

Leonard.

[Norvin]

Thanks Leonard,
are you in the Brisbane region?, last checks I will perform before trying the ecu will be to get the injectors re-tested somewhere other than suzuki and go through the coils, crank and cam sensors and connections between.
Thanks John.

[Legend]

I'm in Sydney, you could send it as a last resort.

Ecu's are pretty tough though, not like the early days of the z1100's.

I bet you relace all those and the problem still persists.

Some times they can be a real pain and you really need another bike to try your bits in one at a time.

Leonard.

[mechanx]

Have you done a pressure test and volume check norvin? I specialise in fuel injection and problems that other can't fix .give me a call 0732051994 . 0412672331. cheers mark ps the pump can still have correct pressure but not volume, so check it ?

[spamanglenn]

Had mine surging a little today.It was at 2%throttle at about 3850 and the wideband was showing approx 14.5/1.So perhaps its just a lean surge.If you have a pc make sure you raise the cells either side of where its playing up.

[Norvin]

Latest update on the surging busa,
hauled the tank and airbox off on the weekend and removed plugs and injectors. Tested crank sensor, cam sensor, coil packs for primary and secondary resistances, injectors for resistance, fitted new plugs and this morning took the injectors to an injector specialist and had him test them as they came off the bike ( complete with inbuilt filters). They tested as brand new and could not be faulted in any way.
On assembling everything back on the bike this morning I decided to re-check fuel flow and pressure again, the return line filled a litre container in 30 seconds which I believe is fine. The fuel pressure is around 38-40psi at idle (10in.mercury) I then connected a vacuum tester to the regulator and at zero vacuum I got 45psi and at 15" it read 36psi and at 20" it read 35psi.
Question is the manual only states that fuel pressure should be 43psi above manifold at all times, are they measuring manifold vac. in negative psi or inches hg. ? One is twice the value of the other .
Any of you guys have any info on the range of pressures the external regulator is supposed to cover ?
P.S I am still looking for someone in the Brisbane area who is willing to either try my ECM in their 99-00 or had a spare I could try for 45 minutes.
Thanks again
John White

[Maj]

Quick check, leave the vac line off and take it for a ride,if that changes the surge just richen it with the powercommander

[BUSGO]

I go back to my original suggestion of replacing the stock fuel lines with proper reinforced injector tube.
The lines may be new and look good but they will buckle and kink at the first sign of heat.
Especially the fuel return line - when the tank is down and you can't see it.
It kinks at the bottom of the tank spiggot unless it is directed exactly right.

[Norvin]

Latest test tried was to connect a fuel pressure and vac gauge to the bars and take for a ride,the bike ran 42-43psi pressure whenever you hit the gas and came down to 0 manifold vacuum, 38-39psi on cruise ( 10in.vac) and 34-35psi on overrun (20+in. vac).
Fuel pressure never waivered at any point and always jumped straight up or down with throttle movement making me feel that fuel supply is definatly not the issue here as the bike ran crap while I conducted this test so still looking for an ecu to try.
Regards John.

[Norvin]

I'm in Sydney, you could send it as a last resort.

Ecu's are pretty tough though, not like the early days of the z1100's.

I bet you relace all those and the problem still persists.

Some times they can be a real pain and you really need another bike to try your bits in one at a time.

Leonard.

Thanks again for the offer, I have got a s/h unit coming my way with the proviso that if it does not solve problem I can return it- I will post result after weekend
regards John