Won't start even with new plugs!

D

DaySleeper

Registered
I had a lean condition on my '07 with 1300 miles that actually leaned fouled one of my plugs. The plugs are always super white when I check them. I have a tuner box that plugs into the injector harness that was supposed to solve that problem but to no avail. The bike totally died and stranded me today so I changed the plugs again but it didn't work this time.

The plugs seem to be firing because I pulled one and it sparked. The fuel injectors seem to be working because I can smell fuel when I crank it. I already removed the tuner box so that can't be it. I have actually checked the fuel pressure before and it was approximately 45psi. It won't start at all now so I'm stuck in the garage at this point. I pushed the bike almost two miles home today so I'm a little fed up with it.

Any chance the computer is just fried? A busa experienced friend said it is very rare for the computer to grenade but I can't believe all the injectors would just die all at once. Any suggestions would be appreciated.

Seth
 
There is a whole section about troubleshooting this.
In my manual it is 4-32 (check the online one)
Go through it and you should be able to fix it.
Check the battery volltage first.
The injectors need 12.7 volts to fire.

Batt Voltage.jpg
 
I'll check the manual like you said. I do have sufficient voltage and the battery is actually on a trickle charger now to prevent it from discharging.
 
I'd remove the "tuner box" and try it again. Any other mods to the engine?
 
A lean fuel condition will not foul plugs. If the electrodes are white or burnt off you have a lean fuel to air ratio.
 
The plugs are brand new. The bike had this problem before but it was only #1 cylinder. When I changed the plugs, the problem went away for awhile. The old plugs were super white and looked like they had just been put in. It is a mystery. Maybe the computer is crap? I heard that was uncommon though.

I did smell fuel one time I cranked it, but I think that was a fluke. The thing just doesn't seem to know when to add fuel. The computer is blind or something.
 
Do you have 13.0 to 13.2 volts at the battery?
Sorry to ask but you have to measure it.
Cranking alone is not a measure, nor is having it on a charger, nor are the plugs sparking.
Some brand new batteries fail this test.
I'm just wondering because it sounds like you have used a lot of that battery testing this.
 
Last edited:
You know, the battery is original and although it cranks, I'm showing only 12.1 volts even though it had charged all night! I'm changing the battery tonight and we'll go from there.

Thanks
 
Hmmmm, some thoughts:

1) If you wanna check the ECU, just swap yours with another Busa (built between 02 and 07)
2) You can remove the injectors, have them all 4 in the common rail, then run the starter. You can see the fuel pushed through the injectors. BUT!!! keep in mind to hold the cable assembly together, otherwise the 42 PSI will blow the line and the injectors apart.

But I think it's just a little something that makes your prob...... hmmmmm

Ciao
D1
 
Well I changed the battery but to no avail.

I think it isn't getting enough fuel to start. I've had the pump out before and inspected everything previously and the pump runs fine. I really think the computer is a dud as hard as it is to believe.
 
The new battery is fine at 12.8. I put a light bulb on the #1 injector plug and it blinked when I cranked it but it was sporadic as it stumbled to try to start. Looked suspicious to me so I poured about a teaspoon of fuel into each throttle body and it fired up for about 5 seconds! So I think it is fair to say I have a fuel problem but I still don't know whats causing it.
 
Yep. It runs normally to prime the injectors then shuts off. I'm going to check the fuel pressure tomorrow again at the fuel rail.
 
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