Pcomp = Normal

Pmax = Low

Conclusion = Late injection

Reasons and remedy:

• Bad quality fuel (longer ignition delay): Check and adjust the temperature and fuel pump timing to get maximum pressure or change the fuel.
• Wrong adjustment of injection pressure: Check and adjust the injection pressure or overhaul the fuel valves
• Wrongly adjusted VIT: Check and adjust the VIT according to makers recommendations
• Wrong fuel pump timing: Check the fuel pump timing and adjust it as per maker's manual
• Leaky fuel pump: Rectify the leak or overhaul the fuel pump
• Chain is slack: Check and adjust the tightness of the chain
• Fuel oil booster pump pressure low: increase the pressure in the fuel oil system or overhaul the pumps.

(ii) The maximum pressure is higher

Pcomp = Normal

Pmax = High

Conclusion = Early injection

Reasons and remedy:

• Wrong injection timing: Check the fuel pump timing and adjust as per maker's manual
• Incorrect VIT setting: Check and adjust the VIT according to makers recommendations
• Leaking fuel injector: Overhaul the fuel valves or change the nozzle

(iii) The expansion curve is lower

Pcomp = Low

Pmax = Low

Conclusion = Low compression pressure

Reasons and remedy:

• Leaky exhaust valve: Overhaul or change the exhaust valve
• Leaky piston rings: Change the piston rings
• Scavenge pressure low: Check the turbocharger and air cooler for fouling, which might be restricting the airflow
• Worn-out liner: Change the liner
• Scavenge ports chocked: Clean the scavenge air manifold

(iv) The expansion curve is higher

Pcomp = High

Pmax = High

Conclusion = high expansion curve

Reasons and remedy:

• Exhaust valve opening late: Check the timing of the exhaust valve opening and adjust the timing
• Engine overload: Reduce the load on the engine