Big Bore 331 FAIL
#1
Big Bore 331 FAIL
Hi guys!
I've got 2014 EFI KLX and last year i decided to swap to 331cc
I purchased bill blue kit, Power commander V and autotune module. On 250cc everything was fine, PCV and autoune worked adequately.
After swapping the cylinder the bike start but work lean
AFR 15-16 on idle, while using heavily trimmed map.
i repalced inlet manifold gasket, inlet clamps, checked several times if there are any intake/exhaust leaks - no result. i checked fuel sprayer on special stand - ok. FI lamp do not flash. Compression is 10.5 (149 psi), timing is good
Here u can see map which autotune is trying to build after several test rides:
Target AFR 13.5 (14 on idle)
as u can see values much too high
I have no idea what to do now and i'm very close to bringing everything back to stock but I really hope somebody here can give me advice
I've got 2014 EFI KLX and last year i decided to swap to 331cc
I purchased bill blue kit, Power commander V and autotune module. On 250cc everything was fine, PCV and autoune worked adequately.
After swapping the cylinder the bike start but work lean
AFR 15-16 on idle, while using heavily trimmed map.
i repalced inlet manifold gasket, inlet clamps, checked several times if there are any intake/exhaust leaks - no result. i checked fuel sprayer on special stand - ok. FI lamp do not flash. Compression is 10.5 (149 psi), timing is good
Here u can see map which autotune is trying to build after several test rides:
Target AFR 13.5 (14 on idle)
as u can see values much too high
I have no idea what to do now and i'm very close to bringing everything back to stock but I really hope somebody here can give me advice
#2
If there are no vacuum leaks in the intake then you need to make sure that the map sensor(air pressure) is sending valid info to the ecm. I don't know if Kawasaki gives output voltages for pressure in the repair manual. The other variable is fuel pressure-it has to be at spec under load or the fuel map will never be accurate.
The ecm calculates pulse width for the injector based on rpm, throttle opening and map. The computer has a calculated airflow map loaded into it from the factory based on the oe throttle body diameter. It knows how much air will flow through the throttle at a given opening angle and pressure difference(map) across the opening. That airflow map should remain constant regardless of displacement- you know the diameter of the hole and the pressure across it. So, I would make sure that fuel pressure is correct and that the map voltage is accurate to oe specs.
Makes fuel injection really attractive compared to carbs, doesn't it...
The ecm calculates pulse width for the injector based on rpm, throttle opening and map. The computer has a calculated airflow map loaded into it from the factory based on the oe throttle body diameter. It knows how much air will flow through the throttle at a given opening angle and pressure difference(map) across the opening. That airflow map should remain constant regardless of displacement- you know the diameter of the hole and the pressure across it. So, I would make sure that fuel pressure is correct and that the map voltage is accurate to oe specs.
Makes fuel injection really attractive compared to carbs, doesn't it...
#4
I bet you could find someone willing to trade their carb gear for your EFI gear...
#6
You mean something like a rheostat, a variable resistor?
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