Ignition System

Question 1

A - a faulty cam shaft position sensor can cause a no-start condition.
B - some vehicles will start without an operating camshaft position sensor.

Answer 1

both correct
The CMP is used with the CKP to detect which cylinder is firing and when to fire the fuel injector. Most vehicles will not start without a CMP signal, however some will.

Question 2

What term describes the condition when the air/fuel mixture is ignited before the spark plug is fired?
A - dieseling
B - preignition 
C - lean ramping
D - early timing

Answer 2

b - Preignition occurs when a hot spot in the combustion chamber ignites the mixture before the spark plug fires.

Dieseling is when the engine continues to run after the key is turned off, caused by the fuel being ignited by the heat of combustion.
Lean ramping is when a vehicle leans out on deceleration to the point of causing a surge.
Early timing (advanced timing) means the spark is delivered to the spark plug too soon.

Question 3

A cylinder misfire will cause all the following except:
A - high hydrocarbon emissions
B - high oxygen level in the exhaust
C - damage to the catalytic converter
D - high carbon dioxide readings

Answer 3

a - true
b - true
c - true
d - false. CO2 is a product of combustion.

Question 4

A - a single cylinder misfire DTC can be caused by a defective coil on some vehicles. B - says a low fuel pump pressure can cause a single cylinder misfire DTC.

Answer 4

A - correct. Coil on plug systems will have a single cylinder misfire.B - incorrect. Low pressure would cause multiple cylinder misfires.

Question 5

A vehicle with DTC code P0304 (cylinder 4 misfire) is being diagnosed.A - high fuel pump pressure could be the cause.B - an open spark plug wire could be the cause.

Answer 5

A - incorrect. High fuel pressure would affect all cylinders.B - correct.

Question 6

All of the following are components of the primary circuit except:A - ignition coilB - ignition switchC - spark plug wireD - battery

Answer 6

c - spark plug wire

Question 7

A - the normal secondary circuit resistance of an ignition coil is low (< 5 ohms).B - the spark plug wire is a secondary component that should have a resistance of 20,000 ohms per foot.

Answer 7

A - incorrect. The secondary circuit of the ignition coil will have high resistance (9,000 - 30,000 ohms). Primary circuit 1-3 ohms.B - incorrect. Spark plug wires should be < 10,000 ohms per foot.

Question 8

A - a shorted coil could affect two cylinders.B - the schematic shows a waste spark ignition system.

Answer 8

both correct. In a waste spark system, the secondary voltage jumps the gap of one spark plug, travels through the block, and then jumps the gap of the second spark plug.

Question 9

Which of the following is the most likely cause of ignition coil failure?A - prolonged open circuit in the secondary.B - open ignition module primary circuit.C - short to ground in the secondary.D - open in the trigger device circuit.

Answer 9

A - increased secondary resistance will cause the firing voltage to be high, damaging the ignition coil.

Question 10

All of the following are true of installing the distributor except:A - the rotor tip must point at the distributor cap terminal for the specified terminal.B - on a 4 cylinder engine, the distributor can be timed just after TDC on cylinder 4.C - a reference mark placed before removal of the distributor aids in reinstallation.D - the crankshaft timing mark must be aligned with the timing indicator numbers.

Answer 10

a - trueb - falsec - trued - true