Misfire In One Cylinder
Misfire in one cylinder
998 5496 ENGINE COOLANT SYSTEM - PRESSURE TESTER 998 5496 Engine Coolant System - Pressure Tester
Checking spark plugs
- Remove all the spark plugs.
Is the spark plug for the relevant cylinder lighter in color than the other plugs?
Yes - Replacing component
No - Checking compression
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Replacing component
This indicates that its cylinder is receiving too little fuel.
- Try a new injector.
Continue - Fault-tracing information
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Checking compression
- Carry out a compression test according to Compression test Compression Test.
Is compression correct?
Yes - Checking cooling system
No - Replacing component
Remedy as necessary, then replace all spark plugs. It is vital that the correct spark plugs are used, see parts catalogue for P/N. Check the spark gap of new plugs before they are fitted. Spark gap should be 0.7 - 0.8 mm. Then continue with Fault-tracing information.
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Replacing component
- Remedy as necessary, then replace all spark plugs.
Note! It is vital that the correct spark plugs are used, see parts catalogue for P/N. Check the spark gap of new plugs before they are fitted. Spark gap should be 0.7 - 0.8 mm.
Continue - Fault-tracing information
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Checking cooling system
- Connect pressure tester 998 5496 ENGINE COOLANT SYSTEM - PRESSURE TESTER 998 5496 Engine Coolant System - Pressure Tester to the expansion tank.
Pump up a pressure of approximately 100 kPa.
Shine a flashlight into the relevant cylinder and check that there is no leakage between the cooling system and the cylinder.
OK - Checking ignition cables
Not OK - Replacing component
Remedy as necessary, then replace all spark plugs. It is vital that the correct spark plugs are used, see parts catalogue for P/N. Check the spark gap of new plugs before they are fitted. Spark gap should be 0.7 - 0.8 mm. Then continue with Fault-tracing information.
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Checking ignition cables
- Remove all ignition cables.
Check the ignition cables for damage, cracks or arcing.
- Then measure the resistance in each ignition cable. Resistance should be 1.5 - 4.5 kohms depending on their length, at +20°C.
- Replace ignition cables that are damaged or have an incorrect resistance.
- Check between ignition cables and the distributor cap and spark plugs for loose connections.
- Remedy if necessary.
Continue - Checking distributor cap and rotor
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Checking distributor cap and rotor
- Remove distributor cap.
- Check distributor cap/rotor for damage, cracks and flashover.
- If a fault is suspected: Clean. Replace suspect components if necessary.
Continue - Checking flywheel/pulse wheel
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Checking flywheel/pulse wheel
- Install new spark plugs.
Note! It is vital that the correct spark plugs are used, see parts catalogue for P/N. Check the spark gap of new plugs before they are fitted. Spark gap should be 0.7 - 0.8 mm.
- Install distributor cap and connect all ignition cables.
- Start the engine and idle it.
- Select Volvo Scan Tool (ST) to read off the values for flywheel adaption B, C, D and E.
Values should be between -0.391 and +0.387.
OK - Checking injector cables and terminals
Not OK - Check engine speed (RPM) sensor probe and the hole to the flywheel/carrier plate for damage, scratches and swarf. If the engine speed (RPM) sensor and hole are OK: Try a new flywheel, reset adaption. Then continue with Fault-tracing information.
Checking for damage
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Checking for damage
- Check engine speed (RPM) sensor probe and the hole to the flywheel/carrier plate for damage, scratches and swarf.
- If the engine speed (RPM) sensor and hole are OK: Try a new flywheel, reset adaption.
Continue - Fault-tracing information
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Checking injector cables and terminals
- Check the cable between the affected injector and engine control module (ECM) for an intermittent open-circuit according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults , an intermittent short-circuit to ground according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults , and an intermittent short-circuit to supply voltage according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults.
- Check affected injector and engine control module (ECM) connectors for loose connections according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults and contact resistance and oxidation according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults.
Continue - Checking for air leakage
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Checking for air leakage
Check for air leakage according to Check for air leaks in the intake system Air Leaks In the Intake System, Checking.
If air leakage occurs remedy as necessary.
Continue - Checking fuel and residual pressures
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Checking fuel and residual pressures
- Check fuel and residual pressure according to Check for air leaks in the intake system Air Leaks In the Intake System, Checking Checking for air leakage in the exhaust system Checking for Air Leakage In the Exhaust System.
Continue - Fault-tracing information
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Fault-tracing information
Information
Fault-tracing information
In case of this defect, troubleshooting is not followed by verification.
The information can be displayed again or the fault-tracing for this fault can be interrupted.
Do you want to view the information again?
Yes - Attempt New Test
No - FAULT FOUND
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Attempt New Test - Checking spark plugs
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