99 busa vry rich at idle and low speed

[DWNBusa]

Hi,
Have a stock 99 Busa that is running very rich at idle. was fine in the morning but when i started it 3 hrs later it wouldn't idle and was running extremely rich.

No F1 codes or light and correct voltage being supplied to the boost sensor. Only way to get it to run is unplug the boost sensor then it is at least ride-able. changed the very sooty black plugs to a new set and no change, swapped out the boost sensor with a known working one and still no change.

Any help would be much appreciated.

Thanks

 

[twotonevert]

Welcome to the org. Someone will be along shortly that can give advice.

 

[cyborgbusa]

could be fuel pressure regulator or senser on back side of air box that has a vacume line running to it. Or when my bike started running real rich found out my ECU was bad. goldenchild is the man to talk to around here.

 

[DWNBusa]

Hi Again,

Have tried new injectors and still no change. I have ordered a new fuel pump and will try that (i think after 13 years the fuel pump deserves a rest). It was mentioned above that the regulator might have problems. Are they servicable or do they just get replaced? there is a very strong fuel smell from the vacuum line to the IAP sensor. Am i looking at a perforated diaphragm?

Thanks

 

[DWNBusa]

Still having the same problem. Have replaced the fuel pump in the housing, cleaned out all the filters in the housing. Tested the fuel regulator and replaced all the vacuum lines. Still very rich.
Anyone?

Thanks

 

[Bobby914]

what about power commander if you have one on it, could be out of whack or maybe lost its map, if not im thinking the ecu is bad, has it been reflashed, have heard of them giving rich problems.

 

[yogster]

I've had very similar experiences with my 2000 Busa , My issue was the return fuel line ( smaller diameter) for the external pump was a bit kinked. check the routing of the line or change it. it worked for me