Board logo

BEC Fuel pressure drop?
DANMAN - 5/4/19 at 11:44 AM

I am having a problem with my 2005 CBR1000 engined Blade in that when I hit about 6800rpm it suddenly dies like it has a massive fuel cut. I fitted a temporary fuel pressure gauge to see what was happening pressure wise and it seems to drop from a constant 50PSI to 40PSI when this happens which makes me think fuel pump/regulator or a problem with the fuel tank breather (although I have checked the breather valve which seems fine). Although a sudden drop in fuel pressure is obviously an issue I wouldn't have thought it would be such a savage drop off in power?

Has anyone else experienced this issue before using the stock fuel pump?

AdamR20 - 5/4/19 at 05:22 PM

Is it going into limp mode possibly? If you've chopped the loom about, removed various bike-related gadgets such as exhaust flaps etc the ECU can throw a wobbly.

OliilO - 5/4/19 at 08:31 PM

Does it pick up again and then pull past 6800rpm?

I had a hesitation when quickly going to WOT in my blade engined car which turned out to be some crap in the bottom sump of the fuel tank that was partially blocking the line at higher flow rates.

DANMAN - 5/4/19 at 11:44 PM

quote:
Originally posted by AdamR20
Is it going into limp mode possibly? If you've chopped the loom about, removed various bike-related gadgets such as exhaust flaps etc the ECU can throw a wobbly.


That is what I thought originally but it hasn't shown any faults from the MIL indicator. I have bypassed the clutch switch, side stand switch and bank angle sensor which were no biggie. I have also re-used the solenoid from the HESD system and have the servo motor for the exhaust flap still connected so the ECU still thinks things are running as normal.

DANMAN - 5/4/19 at 11:53 PM

quote:
Originally posted by OliilO
Does it pick up again and then pull past 6800rpm?

I had a hesitation when quickly going to WOT in my blade engined car which turned out to be some crap in the bottom sump of the fuel tank that was partially blocking the line at higher flow rates.


I can't get it past 6800rpm unfortunately, although once it did manage to rev out to about 8000rpm but every other time it cuts out at about 6800rpm.

All the fuel lines, fuel filter and the fuel tank itself are all new and I was very thorough about cleanliness when putting everything together and I have only done about 50kms since, although I guess something could have got in there.
I have checked the breather pipe feeding into the tank which isn't blocked but perhaps it isn't big enough (the same 6mm ID as the fuel line). I might try running it without the fuel cap on and see if it makes any difference.

DANMAN - 6/4/19 at 04:42 AM

What size fuel line have others been using from the factory pump on EFI 1000cc engines?

[Edited on 6/4/19 by DANMAN]

AdamR20 - 6/4/19 at 12:44 PM

8mm on mine, using stock fuel rails, works fine.