How do I do the 'A adjustment' for the stepping motor and fuel pump on a 2006 Kobelco SK135SRLC-1E? I just replaced the CPU and need the setup steps.

[James R.]

Hey everyone, I just replaced the CPU controller on my 2006 Kobelco SK135SRLC-1E.

I've finished the minor adjustments, but I'm stuck on the "A-adjustment" for the stepping motor and fuel pump. Does anyone have the step-by-step instructions or the button sequence on the monitor to get this calibrated?

I want to make sure the fuel settings are 100% correct before I get back to work. Any help or a quick guide would be much appreciated!

 

[NickBriston]

Hey @James R. from what I've seen, the A-adjustment is basically calibrating the stepping motor to match fuel delivery, so you'll need to enter service mode on the monitor and follow the calibration sequence. Definitely worth grabbing the Kobelco service manual or using diagnostic software to get the exact steps so you dno't risk overfueling

 

[IamBruce_Driver]

Yeah, that part confuses a lot of people-A-adjustment is not just button pushing, it's mechanical + electronic calibration together.

Entering A-adjustment mode

• Turn the key ON (engine OFF)
• Hold the mode switch until the display changes (clock shows)
• Set the throttle to low idle
• Press and hold the buzzer stop switch (~5-10 sec) until STEP 1 STEP 2 shows

Important part (where most get stuck)

• At STEP 2 (GAP STOP), the CPU will move the stepping motor to the low stop automatically
• Now you go to the engine side:
• Pull the fuel rack lever against the low stop bolt
• Reinstall and align the linkage between the stepping motor and fuel pump
• Adjust the linkage so everything lines up properly

Critical adjustments

• Set clearance between the lever and stop bolt to about 0.1 mm using a feeler gauge
• Make sure the stepping motor shaft protrusion and linkage alignment are correct
• Tighten everything evenly (don't twist the linkage)

Final calibration

• Go back to the cab, press the buzzer stop again
• You'll see STEP 3 (start engine)
• Then STEP 4 MEMORY, where the machine cycles RPM automatically (takes ~3 minutes)

 

[jagatlalon]

After replacing the CPU on a 2006 Kobelco SK135SRLC-1E, you need to do the A adjustment from the monitor panel to calibrate the stepping motor and fuel pump. Turn the key ON without starting the engine, enter the service mode using the monitor buttons, and find the A adjustment option. Run the stepping motor adjustment first, then do the fuel pump adjustment. Keep the throttle at low idle and make sure there are no error codes. If it doesn’t complete, recheck the wiring and connections, and it’s a good idea to follow the manual to avoid any setup issues.