FIRING ORDERFIRING ORDER

Report by: Franz Jefferson B. MonjardinReport by: Franz Jefferson B. Monjardin

What is a firing order?What is a firing order?

It is the sequence It is the sequence of power delivery of power delivery of each cylinder an of each cylinder an a multi-cylinder a multi-cylinder reciprocating reciprocating engine.engine.

How is it done?How is it done?

it is achieved by it is achieved by sparking of the sparking of the spark plugs in a spark plugs in a gasoline engine in gasoline engine in the correct order, the correct order, or by the sequence or by the sequence of fuel injection in of fuel injection in a diesel engine.a diesel engine.

Why is it important to have a Why is it important to have a correct firing order?correct firing order?

It is critical to minimizing vibration.It is critical to minimizing vibration.

Achieve smooth run, for long fatigue Achieve smooth run, for long fatigue life and user comfort.life and user comfort.

A vehicle will run rough or may not A vehicle will run rough or may not run at all if the wrong firing order is run at all if the wrong firing order is utilized.utilized.

Firing order by numberFiring order by number In a straight engine In a straight engine

the spark plugs (and the spark plugs (and cylinders) are cylinders) are numbered, starting numbered, starting with #1, from the with #1, from the front of the engine to front of the engine to the rear.the rear.

Some manufacturers Some manufacturers place the engine place the engine “backwards”, with #1 “backwards”, with #1 towards the firewall.towards the firewall.

1-3-5-2-4 would be the firing order 1-3-5-2-4 would be the firing order

for this 5 cylinder radial engine.for this 5 cylinder radial engine.

““V” engineV” engine

In a “v” engine the right bank is In a “v” engine the right bank is numbered first, followed by the left numbered first, followed by the left bank.bank.

The numbers are usually cast on the The numbers are usually cast on the cylinder head or the intake manifold cylinder head or the intake manifold or the valve covers.or the valve covers.

V6 engineV6 engine

V4 firing orderV4 firing order

1-3-4-21-3-4-2

This means the first cylinder is fired This means the first cylinder is fired first, followed by the third, fourth and first, followed by the third, fourth and second.second.

Conventional engineConventional engine The correct firing order The correct firing order

is obtained by the is obtained by the correct placement of correct placement of the spark plug wires on the spark plug wires on the distributor.the distributor.

In a modern engine In a modern engine with an engine with an engine management system management system and direct ignition, the and direct ignition, the electronic control unit electronic control unit (ECU) takes care of the (ECU) takes care of the correct firing sequence.correct firing sequence.

THANK YOUTHANK YOU

The EndThe End