The turbo diesel engine is a favorite of enthusiastic motorists from Europe and Asia. This is due to the fact that diesel engines are more economical to run compared to a comparable gasoline engine and produce significantly more torque which is responsible for the massive pulling power that TDI (turbocharged direct injection) and other diesel engines are known for. Diesel engines have significantly lower NOx (Nitrous Oxide) emissions than a petrol powered car, and the availability of low sulfur diesel fuel in the market further reduces the occurrence of black smoke and soot.
If a sudden loss of power is felt or excess smoke is evident on the tailpipe, then adjusting the timing could bring improvements and sort out the power issue. Please note that different makes and models of diesel engines will cause the procedure to vary, but the basic fundamentals are almost the same.
How to Adjust the Timing
Brand new cars and trucks equipped with a turbo diesel engine will generally be tuned towards a modest power input with little or no smoke but should be adjusted as the engine piles up on mileage. This is accomplished by adjusting the pump to increase the flow of fuel in the combustion chamber to produce power. However, engine timing should also be measured and adjusted to produce the desired effect.
Step 1 - Warm-up
Start the engine and let it warm to a normal operating temperature. Shut the engine off when it is fully warm. Never attempt the following procedures with your engine running, as this could lead to serious engine trouble and costly damage on the injection pump gear train.
Step 2 - Install the Luminosity Probe
Diesel engines rely on a timing meter that employs luminosity and magnetic probes to properly detect ignition patterns. A proper diesel timing meter is an essential tool to accurately read ignition timing. With a timing meter at hand, carefully remove the appropriate glow plug and install the luminosity probe.
Step 3 - Connect the Meter to Vehicle Battery
Power the meter via the engine battery and install the magnetic probe in the front cover holder. Ensure no cables are dangling and are in the way of the engine fan to prevent accidents when the engine is started.
Step 4 - Check Existing Timing
Start the engine and check the timing on various intervals to establish an accurate baseline for analysis.
Step 5 - Adjust Engine Timing
Rotate the injection pump to increase or decrease engine timing as needed. This is usually accomplished by loosening the bolts and rotating the injection pump in small increments either clockwise or counterclockwise. Re-tighten the bolts after adjustment.
Step 6 - Observe and Assess
Observe idle clatter and smoke before going for a test drive. A lean burn is usually preferred for the perfect balance of less smoke and ideal power delivery. Refer to your vehicle owner's manual for proper timing figure.
Adjusting the timing on a turbo diesel engine is easy, but it does require some technical knowledge and proper diagnostic equipment to properly accomplish. Remember that proper tuning can only be achieved through numerous adjustments and test drives to properly determine the right increment that strikes the balance between power, fuel economy, and emissions.