What Causes Difficulty in Starting a Hot Pajero?
2 Answers
Difficulty in starting a hot vehicle is related to many systems, such as the battery, throttle body, coolant temperature sensor, etc., and also to the mechanical parts of the engine, such as valve sealing. In a hot state, the thermal expansion of the engine can increase engine resistance, leading to difficulty in starting. Reasons for difficulty in starting a hot vehicle include: 1. Possible fuel injector leakage: The more severe the fuel injector leakage, the richer the air-fuel mixture becomes, resulting in difficulty in starting a hot vehicle. 2. Engine carbon buildup: Carbon buildup has a strong adsorption effect on gasoline. If there is significant carbon buildup on the intake valves, throttle, or pistons, it can easily adsorb some fuel, leading to an overly lean air-fuel mixture and affecting startup. This situation can also occur during cold starts. 3. Poor fuel quality: If the fuel itself is highly volatile, it can easily form high vapor pressure in the fuel rail. When this pressure exceeds the pressure of the fuel supply system, it can cause vapor lock, resulting in overly lean fuel vapor from the injector and difficulty in starting. 4. Issues with the intake air temperature sensor: A faulty intake air temperature sensor can lead to difficulty in starting a hot vehicle. 5. Damaged carbon canister purge valve: During a hot start, fuel atomization is normal, and no additional fuel vapor is needed. If the carbon canister continues to supply fuel vapor to the intake manifold, it can cause an overly rich air-fuel mixture, leading to difficulty in starting.
I previously encountered difficulty starting my Pajero when the engine was hot, which was mostly caused by fuel system issues. For example, the fuel pump is prone to overheating when the engine is hot, causing gasoline to vaporize and form vapor lock, preventing pressure from building up and making it hard to start. Additionally, when fuel injectors are clogged with carbon deposits, the air-fuel ratio becomes inaccurate during hot starts, and fuel flow is disrupted, affecting ignition. This requires checking the fuel pressure gauge and cleaning the fuel injector filter screen. Moreover, the Pajero's V6 engine is particularly sensitive to fuel quality—using low-quality gasoline makes it more prone to problems. It's recommended to regularly replace the fuel filter and use 95-octane gasoline for system maintenance. Ignoring this issue can lead to black smoke from the engine or sluggish acceleration, so it's safer to have it tested at a professional shop. Don’t let a minor issue turn into a major repair expense.
