CF. Mechanical Overview

CF. Mechanical overview




Leakage from air and vacuum hoses
In the event of leakage from the intake hoses, the engine usually receives too much air. This affects several electrical components such as the idle valve and lambdasond.
After driving for a while with leaking hoses, fault codes for the adaptive lambda regulation (2-3-1, 2-3-2), and adaptive idle control (2-3-3) may be seen.

Air filter / air intake.
A clogged air filter / air intake prevents the engine from receiving sufficient air. This is most noticeable upon acceleration and at high loads. After driving for a while with clogged air filter / air intake, a fault code for the adaptive idle control (2-3-3) may be seen.




Exhaust system
In the event of leakage from the exhaust pipe, air enters the exhaust system owing to pressure pulse effects. If the leakage is ahead of the lambdasond, this air comes from outside and fools the sond into thinking that the mixture is too lean, thus affecting the setting of the adaptive lambda regulation.
After driving for a while with a leaking exhaust system, any of the fault codes for the adaptive lambda control (2-3-1, 2-3-2) may be seen.




Injectors
If one or more of the injectors is clogged with dirt, the engine will not receive sufficient fuel. The engine will operate on a lean mixture which in turn affects control of the lambdasond.
After driving for a while with clogged injectors, any of the fault codes for adaptive lambda control (2-3-1, 2-3-2) may be seen.




Fuel pressure
To ensure that the correct amount of fuel is delivered, it is important that fuel pressure is in accordance with specification. Fuel pressure which is too low means that the engine runs lean while high fuel pressure causes the engine to run rich and results in driveability problems.
After driving for a while with too low/too high fuel pressure, fault codes for adaptive lambda control (2-3-1, 2-3-2) may be seen.

Residual pressure
If the residual pressure is too low, this is an indication of a leak in the pressure regulator or an injector or cold start injector.
Hot-starting problems.
After driving for a while with a leaking injector, fault codes for adaptive lambda control (2-3-1, 2-3-2) may be seen.




Fuel filter
A clogged fuel filter reduces fuel pressure. See fuel pressure, residual pressure.
After driving for a while with too low fuel pressure, fault codes for adaptive lambda control (2-3-1, 2-3-2) may be seen.




Fuel pump
A poor fuel pump does not produce sufficient fuel pressure. See fuel pressure residual pressure.
After driving for a while with low fuel pressure, fault codes for adaptive lambda control (2-3-1, 2-3-2) may be seen.

EVAP system
A defective EVAP system will cause uncontrolled induction of fuel vapour into the engine.
After driving for a while with a faulty EVAP system, the fault code for adaptive lambda control (2-3-1) may be seen.




Throttle housing and control pulley
If the throttle is set too low the engine gets too little air and may die. If it is set too high petrol vapour can be inducted in via the EVAP system and result in too rich a fuel/air ratio.

Fuel quality
Fuel should not be contaminated with dirt or water. Poor fuel quality may result in starting and driveability problems.




Throttle switch
If the throttle switch is incorrectly adjusted so that the control unit does not receive information that the throttle valve is in the idle position, then engine idle speed is not controlled via the idle valve. If there is no idle switch information, the engine only receives air via the throttle valve. If the valve is correctly adjusted, idle speed will be set at approx. 500 rpm. If the valve is set too low the engine will get too little air and cut out.
Low idle speed and difficulty in starting the engine, especially when cold.




Valves
Faulty valve clearance, worn or burnt valves can result in poor acceleration and lack of engine power, which is most noticeable at idle speed.

Compression
Uneven compression may result in poor acceleration and lack of engine power or uneven running, which is most noticeable at idle speed.




Camshaft adjustment
If the camshaft is incorrectly adjusted relative to the crankshaft, the valves open too soon or too late. As a result the engine lacks power and does not accelerate.




Crankshaft ventilation
Crankshaft ventilation is connected to the intake manifold to draw vapor from the crankcase. If the oil is contaminated with fuel, the fuel/air mixture will be too rich, thus affecting the adaptive lambda control.
After driving for a while with contaminated engine oil, either of the fault codes for adaptive lambda control (2-3-1, 2-3-2) may be seen.




Carrier plate / flywheel
If the carrier plate / flywheel is uneven or otherwise damaged, the impulse sensor will send the wrong signal to the control unit. Carrier plate is easily damaged. Never use it to turn engine or as counterhold.
If the carrrier plate I flywheel is damaged, the engine will not start, may be difficult to start, runs unevenly or cuts out.




Spark plugs
Worn spark plugs result in poor combustion in the cylinders which is most noticeable in the form of an uneven idling speed and significantly raised HC values.

Ignition cables / distributor / rotor
Cracks in the distributor I rotor or damaged ignition cables result in poor combustion in the engine, the results of which are most noticeable in the form of weak engine performance, uneven idling speed and significantly raised HC values.

Rotor
Cracks or excessive resistance in the rotor prevent the engine from firing on all cylinders, resulting in poor combustion in the engine. This is most noticeable in the form of weak engine performance, uneven idling speed and significantly raised HC values.