Land Rover Repair: Diesel Engine Hard Starting Tips, fuel air mixture, freelander td4

Question
Hi,

I have no problems starting my Freelander TD4 first thing in the morning ... the problem is that after driving somewhere (up to 2 hours after arriving) I can SOMETIMES have a real problem starting it again. The engine turns over fine and sometimes tries to fire. It can take a long time trying before it will start, but after it has the engine runs fine.

The tank fuel pump and a pressure switch(?) have been replaced at considerable cost but I still have the problem.

I would be most gratefull for any advice.


Best Regards,


Dave.

Answer
Hi Dave,

here's what I know about hard starting diesel engines:

Diesel Engine Hard Starting Tips

You may have a problem with your glowplugs or controller, however, there are many things that can affect how your diesel engine starts.

Glow Plugs and Controller:
Many diesel engines utilize glow plugs and controllers to assist with starting. Burned out glow plugs or a malfunctioning controller are two very common problems with diesel engines that greatly affect startability. These are some of the first things to look at since they are relatively easy to check.

Cranking Speed:
If your diesel engine is turning too slow when you try to start it, you may have a problem with your connections, starter or battery(s). Diesel engines need to turn relatively quickly to build the heat and compression needed to ignite the fuel / air mixture. Many things can contribute to worn starters and batteries, from a malfunctioning alternator to poor connections.

Injection Pump and Injectors:
A worn or malfunctioning injection pump will not provide sufficient fuel that is needed fuel to start a diesel engine, and worn or malfunctioning injectors may not be atomizing the fuel properly to mix with the compressed air. These are two common items that may need some attention as well.

Compression:
A diesel engine needs good compression to start properly. Compression builds heat, and that heat is very important to get the engine started quickly. Low compression is normally found on engines with high miles / hours, or with something that has prematurely gone wrong with the engine. A compression check during a LR service visit should be performed.

Timing:
Fuel needs to be injected into the cylinders at the precise moment for optimum starting. Timing should always be checked by a LR mechanic with the proper equipment.

Air In Fuel Supply:
If your engine starts well when it is warm or hot, but not after it has been shut off for short or extended periods, you may have a simple problem of air getting into your fuel supply line when it sits for a certain amount of time. Diesel fuel injection pumps are designed to deliver small amounts of precisely metered fuel to the injectors. The presence of air will usually create an air lock that is very difficult to overcome by cranking on your engine. This simple problem can be difficult to track down to the exact location, and may exist anywhere from your fuel tank right up to your injection pump inlet.

(Thanks to Bosch for the above!)

Regards,

JohnMc