- The purpose of a glow plug is to heat the cylinder up so that it is hot enough for ignition.
- You can test with an Amp meter. You do this by placing one end of the amp meter to the top of the glow plug and the other end to the body of the glow plug (each glow plug should read 10 amps).
What's the difference between diesel and petrol engine?
- Both engines are constructed the same e.g. the design, however diesel engines do not have spark plugs to ignite the fuel. Instead they have glow plugs to heat up the cylinder before the car can be cranked over.
- Also, diesel engines are more heavy duty and last longer than petrol engines.
What are the 4 things to check on a non-start?
- Air: Oxygen surrounds us, so there will most likely be are present.
- Fuel: You can check if the injectors are injecting fuel into the cylinders.
- Heat: Check that the glow plugs are working and heat up quickly (between 5-10 seconds).
- Compression: Check the compression on all the cylinders. On a diesel engine the compression should be around 450-500 psi. To do this, take out the glow plug and put in a compression gauge. If it's not at 450-500 psi you should check to see if the head gasket or piston rings are broken.
How do you bleed a diesel engine?
- Crack each injector and crank the engine over until fuel comes out of the injector.
What is the Diesel Bug? How is it caused?
- The diesel bug is a build up of algae inside the fuel tank.
- It is caused by not having a full tank of fuel and then not running the engine for a long period of time e.g. 6 months. This happens because of condensation in side the fuel tank.
How does an injector work?
- It injects high pressure fuel into the cylinders. This happens because the fuel starts in the fuel tank, it then goes into the diesel pump and then into the fuel rail. As the fuel goes along, it has to fit into a smaller space every time. This builds up the pressure, by the time it gets to the injector it is at its highest pressure.
What is the purpose of an injector pump?
- The purpose of an injection pump is to make sure that the injector inject at the correct time. To make sure of this you have time the injection pump in time with the crank shaft.
How do you time a diesel engine? What do you need?
- Firstly, you line the crank shaft up to TDC.
- Next, you put the gauge in to the injection pump.
- After that, rotate the crank shaft backwards 30 degrees.
- Turn the gauge to 0.
- Rotate the crank shaft forward to 2 degrees.
- Check the reading on the gauge, if it's within the manufactures specs then it's fine. If not, you have to undo 2 bolts on the injection pump and move the unit forward or backward to get it to manufactures specs.
You need a socket set to undo the bolts and rotate the crank shaft.
What is the difference between a diesel and petrol piston?
- A diesel piston has a grove in the top to give maximum surface area for combustion. It also has slots on the sides that have rings in them to generate friction and in-turn extra heat.
This is a Diesel Piston
This is a Petrol Piston
How does a turbo work?
- On one side, the turbo takes the exhaust and spins it through its turbine to be released at a higher speed. On the other side, the turbo takes in cold air and pushes it into the inter-cooler to then be pushed into the intake side.
What is common rail?
- Common Rail injection is very similar to fuel injection on a petrol engine. It uses a very high pressure fuel rail that feeds individual injectors. The fuel rail has a pressure of about 15,000 psi.
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