Is your vehicle hard to start when cold or hot and even cutting out under load?

Our technicians are highly trained and well experienced to resolve your diesel injector issues. Rest assured that all our work is guaranteed and we’ll always have a solution to your faulty diesel injector

Almost any diesel engine can have problems starting at some point and they can be very often on common rail engines as seen on vehicles including:
Audi, BMW, Mercedes, Peugeot, Citroen, Fiat, Vauxhall, Mazda, Ford

There can be various reasons for this issue, but a very common one is injector failure.

The diesel engine is an internal combustion engine within which ignition of the fuel takes place when fuel is injected at high pressure into the combustion chamber. Diesel engines work by compressing only the air,in contrast to petrol engines where fuel is mixed with compressed air and then ignited by a spark.

Here we have a diesel injector x-ray, where we can see all internal components.

Diesel fuel injectors require a set pressure of a minimum of 150 bars in order to start injecting fuel to the the combustion chamber.A high pressure fuel pump builds pressure into the common rail which feeds the injectors. Each injector has its own regulating valve to control fuel pressure. When the injectors valves fail pressure built by the pump is lost quickly so the pump has to work harder in order to reach the minimum pressure required to start the engine.

rail_injectorThis means that the engine has to turn more before it starts. If a diesel injector has failed it will make the engine hard to start, possibly cutting out under load due to excess fuel leak on return.

In order to establish if an injector is faulty due to loose of pressure, an injector leak test has to be carried out. By doing this the quantity of fuel returned within space of time is measured at a set supply pressure and compared against specification. An injector returning more than the other is suspected to be weak or can be faulty. In the case above injector cylinder 3 is returning double than injector cylinder1.

If your engine is hard to start at hot rather than cold, this could be an indication of loss of pressure in high pressure common rail.

We diagnose hard to start engine issues and carry out repairs including injector replacement for most vehicle makes and model. Contact us with your vehicle details and we’ll be more than happy to advise or resolve your hard to start issue.