Fired up, ready to go

This month Trevor has mostly been dealing with unwilling Td5s

THE Land Rover Td5 engine is a very fine piece of mechanical and electrical engineering and has proved to be very reliable and tuneable over the years. The fivecylinder diesel is normally very easy to start, as long as everything is in tip top condition. If your Td5 engine becomes more and more difficult to start, it is a sure sign that something is not quite right.

I recently encountered two Td5 vehicles at my workshop that were difficult to start or refused to start at all. The first one was a Discovery 2 that was in for a new chassis. It had been driven to me but the owner reported starting difficulties. In fact, having been sat outside the workshop for a week, awaiting its turn, we had to push it in to begin work on it. Following the re-chassis and the fitment of a new fuel pressure regulator, injector harness and fuel filter housing, the engine wouldn’t run. The problem was eventually traced to a faulty connection within the plug to the crankshaft sensor. With this rectified, the engine fired up easily on each turn of the key.

Coincidentally, a Defender 90 Td5 that was brought to me around the same time – because the owner couldn’t get it to start, after he had changed the clutch – was also down to the crankshaft sensor. This time it simply had not been plugged in!

My own Defender 90 Td5 had recently become reluctant to start. The engine had to be turned over for a long time before it would bark to life. I could also hear a fair bit of gurgling from the fuel system, indicating that air was getting in some way or other. I changed the fuel pressure regulator for a new OEM unit because a slight diesel leak had developed from it. However, this was not the solution – the engine remained difficult to start.

The fuel filter housing was in good condition, with no leaks – which can occur when the alloy housing material becomes porous – so this was unlikely to be the culprit. I could have dropped the fuel tank to check the fuel pump and the fuel lines local to the tank, as these have been known to develop leaks if they are allowed to rub on the chassis.

But there is another common way in which air can get into the fuel system – tired and worn injector (copper) washers and injector seals. As the washers and seals had never been replaced, I decided that this would be my next course of action.

I removed the engine’s acoustic cover and rocker cover to allow access to the injectors. The injector wiring harness was next to come off, followed by the rocker shaft. This allowed me to remove each of the injectors in turn and replace the copper washer and injector seal on each. The old copper washers did look quite thin and pitted around the inner circumference, although I had not detected the smell of diesel in the engine oil. Were my efforts going to provide the solution?

The injectors were all fitted back in place, rocker shaft refitted and adjusted correctly, and the rocker cover bolted down with a new gasket. I was ready to start the engine. A fuel priming cycle was performed (ignition on and five pumps of the throttle), then the engine was turned over.

The first attempt proved to be a slow start, perhaps due incomplete priming, but afterwards the Td5 began to improve in its starting performance. Now, after having driven the Defender a few miles, when I turn the key, it starts straight away.

This is great news because the Defender has to go back to work – the first job being to trailer a non-running 110 station wagon to the workshop.