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DannoXYZ · May 13th, 2023, 04:36 PM

Hi Scott, Greetings & Salutations!!

Anything that is shared between cylinders is fine: battery, airbox, air-filtre, petrol tank, fuel-pump, fuel-filtre, fuel-hoses, fuel-rail, FPR.

Problem is most likely in wiring between ECU to sensors, injectors and coils. If you've swapped injectors and coils and they all work in #2, problem is wiring somewhere.

1. Very first thing always, is measure valve-clearances. Are they within spec? Adjust all to large end of tolerance range.

2. It's possible fuel-rail has clog and not delivering to one injector. Remove rail and inspect end-to-end

3. measure fuel-pump flow-rate. Disconnect fuel-hose from rail, aim into measuring-cup. Crank engine for 10s. How much petrol did you collect? Photo of different bike, but same procedure:

4. measure pressure in fuel-rail. Crank engine for 10-sec. What is pressure in fuel-rail? Again, picture from different bike, same test and procedure

5. Inspect all terminals in all connectors on harness for looseness, bending and corrosion. Sometimes, terminals can get tweaked and pushed out of connectors when plugging in.

6. Measure all wires end-to-end for breaks

7. Disconnect all injectors and coils. key ON, measure voltage at each terminal of every injector and coil connector. Post your results here; 8 separate measurements

8: functionally verify coils and sparks. Pull coils and insert plug. Ground case of plugs, to engine or with jumper cable to battery -neg. Crank engine, is there strong bright blue spark on both plugs?

9. verify injector functionality. Pull fuel-rail with injectors attached, leave clips on. Put little cups under each injector. Crank engine for 10-sec. How much petrol did you collect in each cup?

10. measure ECU signal to each injector & coils with oscilloscope. Should look like following trace (4 separate measurements).

11. inspect each sub-throttle for proper operation. Although they really only make difference coming just off-idle, if one was stuck open or closed, it may cause issues. But really only at partial-throttle/low-RPM. I usually disable them completely when replacing EFI system anyway.

May 13th, 2023, 04:36 PM	#2
DannoXYZ ninjette.org certified postwhore Name: AKA JacRyann Location: Mesa, AZ Join Date: Dec 2011 Motorcycle(s): CB125T CBR250R-MC19 CBR250RR-MC22 NSR350R-MC21 VF500F CBR600RR SFV650 VFR750F R1M ST1300PA Valkyrie-F6C Posts: A lot. MOTY - 2018, MOTM - Nov '17	Hi Scott, Greetings & Salutations!! Anything that is shared between cylinders is fine: battery, airbox, air-filtre, petrol tank, fuel-pump, fuel-filtre, fuel-hoses, fuel-rail, FPR. Problem is most likely in wiring between ECU to sensors, injectors and coils. If you've swapped injectors and coils and they all work in #2, problem is wiring somewhere. 1. Very first thing always, is measure valve-clearances. Are they within spec? Adjust all to large end of tolerance range. 2. It's possible fuel-rail has clog and not delivering to one injector. Remove rail and inspect end-to-end 3. measure fuel-pump flow-rate. Disconnect fuel-hose from rail, aim into measuring-cup. Crank engine for 10s. How much petrol did you collect? Photo of different bike, but same procedure: 4. measure pressure in fuel-rail. Crank engine for 10-sec. What is pressure in fuel-rail? Again, picture from different bike, same test and procedure 5. Inspect all terminals in all connectors on harness for looseness, bending and corrosion. Sometimes, terminals can get tweaked and pushed out of connectors when plugging in. 6. Measure all wires end-to-end for breaks 7. Disconnect all injectors and coils. key ON, measure voltage at each terminal of every injector and coil connector. Post your results here; 8 separate measurements 8: functionally verify coils and sparks. Pull coils and insert plug. Ground case of plugs, to engine or with jumper cable to battery -neg. Crank engine, is there strong bright blue spark on both plugs? 9. verify injector functionality. Pull fuel-rail with injectors attached, leave clips on. Put little cups under each injector. Crank engine for 10-sec. How much petrol did you collect in each cup? 10. measure ECU signal to each injector & coils with oscilloscope. Should look like following trace (4 separate measurements). 11. inspect each sub-throttle for proper operation. Although they really only make difference coming just off-idle, if one was stuck open or closed, it may cause issues. But really only at partial-throttle/low-RPM. I usually disable them completely when replacing EFI system anyway. Last futzed with by DannoXYZ; May 14th, 2023 at 01:00 PM.