Checking compression - MB/1B/MC-2 engine

Checking compression pressures

• First test with spark plugs tight in all other cylinders
• Minimum oil temperature 30°C
• Throttle valve fixed open
• Disconnect 3-pin connector [1}
• Use non-return (ratcheting) compression gauge
• Double-check vehicle out of gear
• Operate starter with remote control until gauge stops rising
• Tolerance 9 bar to 13 bar, wear limit 8 bar, maximum delta 2.5 bar
• Repeat test with other plugs out - investigate discrepancies