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MG Ignition Problems

MG Ignition Problems

We have in stock a full range of distributors brand new and fully reconditioned for all MG cars these units are sold as exchange units, they are covered by our 12 month unlimited mileage warranty. We can also supply used units these are fully tested and come with 6 months warranty.

MG FREE TESTING SERVICE

Or you can take advantage of our free testing and repair service, we only charge you the postage if not faulty, and only charge for parts if faulty and you will get 1 years warranty on any work carried out by our self’s, for the more confident, we can supply full repair kits which come complete with new coil, ignition module with sensors, seals, distributor cap and rotor arm and a bag of new screws everything you need to fully recondition your unit. All parts with 1 years warranty, if you know the part that has malfunctioned we can supply just that part thus saving you time and money.

MG DISTRIBUTOR PROBLEMS:

MG distributor units are fitted with a hall affect sensor as the distributor rotates, a signal is sent to the E C U, which in turn sends a pulse to the ignition module which then amplifies the current to send to the coil when this sensor malfunctions no signal is made hence no spark at the plug.
MG CAR PARTS
Remedy:

Fitting new hall senor is the only solution we can supply these sensors for any MG distributor. They are easy to fit, taking only 15 minutes. Or you can send to us and we will fit free of charge.
MG Lambda sensor problems. These are also called Oxygen Sensors and O2 sensors

These are common faults we can supply the original Lambda sensor made in Italy by the OE manufacture. Please click here.

Symptoms of a faulty Lambda sensor

Erratic Idle.
Can be caused by the faulty sensor giving the wrong out put signal to the ECU, if the heater element fails the car will run to rich as the ECU thinks the car is running at a cold temperature causing the ECU to constantly try to cut the mixture strength back to correct the situation. Beyond which the flame front will not burn cleanly, leading to misfire and increased emissions. Often black smoke from the exhaust is emitted

MG Airflow meters

Air Flow Meters are a common problem on most European cars at the moment and MG are no exception. Air Flow Meters measure the amount of air passing into the engine from which the computer can work out how much fuel to add to get the perfect mixture for that specific throttle opening, the computer does this by referring to a map in its memory.
The Air Flow Meter works by seeing how much current it takes to keep a wire at a specific temperature. The fault will often not be shown on diagnostic system as the meter will still be operating within the limits the computer believes are OK, but putting the correct amount of fuel in for idle when the throttle is fully open will result in a very weak mixture and thus a lack of power.
The air flow meters will occasionally fail completely which will bring up a light on the dash and the symptoms described here are only the usual ones, as we have known the fault to become apparent in other ways.
The easiest way to check if the Air flow meter is faulty is to unplug the wiring loom start the car if the car runs ok then the fault is with the airflow meter.
Luckily Airflow meters are very easy to fit and normally only take 5 minutes to fit you do not need any special tools to fit them and with a very small purchase price they are no major problem when there go wrong.

Beware however as Lambda (or Oxygen) sensors in the exhaust can also give very similar symptoms to Air Flow Meters.

MG Ignition coil Problems

The working principle of Ignition coils have not changed much since the internal combustion engine first started life more that 100 years ago. The function of any ignition coil is to convert a low voltage, usually 12 volts, into a voltage high enough, 35,000 volts and up, to jump the spark plug gap and ignite the fuel-air mixture in the combustion chamber. It performs this function by making use of the principle of induction. The inside of a coil consist of primary and secondary windings of wire coiled around a vertically mounted soft-iron core. Because of the ratio of primary to secondary windings, a small input voltage is transformed into a very large output voltage.
Many of today’s vehicles MG are equipped with D.I.S. or distributor less ignition systems. These vehicles do not use a distributor. In place of the distributor they use sensors to fire an ignition coil pack. There are two styles of ignition coil packs. The first type of coil pack has all the coils mounted on one mounting pad then bolted on top of the spark plugs these are known as cassette coil. If any of the coils are found to be defective, the entire coil pack must be replaced.
The second type of ignition coil has all the coils mounted individually on to the spark plugs these are commonly called Pencil type coil. On this system, if one coil is found to be defective, it may be replaced as a separate unit. Testing procedures on these coils are the same as the procedures described below. As always you should refer to a specific automotive service manual for details and specifications on your vehicle.

MG Crankshaft Sensors

A Crankshaft Sensor is a component used in an engine to monitor the position or rotational speed of the crankshaft. This information is used by engine management systems to control ignition system timing and other engine parameters. Before electronic crank sensors were available, the distributor would have to be manually adjusted to a timing mark on the engine.
The crankshaft sensor can be used in combination with a similar camshaft position sensor to monitor the relationship between the pistons and valves in the engine, which is particularly important in engines with variable valve timing. It is also commonly the primary source for the measurement of engine speed in its RPM.
Crankshaft sensors in engines usually consist of magnets and an inductive coil, or they may be based on magnetically triggered Hall Effect semiconductor devices. Common mounting locations include the main crank pulley, the flywheel, and occasionally on the crankshaft itself.

MG Camshaft Sensors

The Camshaft Sensor is used to help the PCM (power-train control module) determine the correct firing order. The engine will not run without this sensor’s input.
The camshaft sensor is a Hall Effect sensor. The Hall Effect type of cam sensor uses notches or shutter blades on the cam gear or balancer to disrupt a magnetic field in the hall effect sensor window. This causes the sensor to switch on and off, producing a digital signal or Hall-effect signal to the PCM that it uses to determine when the number 1 cylinder comes up on top-dead centre (TDC). This sensor information is used to phase the sequential firing of the fuel injectors during normal SFI operation.

MG MAP Sensors

A MAP sensor (manifold absolute pressure) is one of the sensors used in an internal combustion engine’s electronic control system. The manifold absolute pressure measurement is critical to an engine’s electronic control unit (ECU) in order to calculate fuel and spark requirements. Not all engines use the speed-density airflow determination method, so not all engines need a MAP sensor. A MAP sensor is almost exclusively used in conjunction with fuel injection.
Manifold absolute pressure is an accurate indicator of the mass of fuel an engine requires, vacuum is only a differential to some other pressure. Carburettors relied significantly on vacuum, and although they were precise, they were not accurate fuel metering systems, and therefore unable to satisfy modern automobile emissions control legislation. Accurate and precise air mass measurement is required to meter fuel mass in a stoichio-metric manner to achieve acceptable emission control under all operating conditions. A MAP sensor is a component used in the speed-density method of accurately determining the engine’s air mass flow rate.

MG Throttle Position Sensors

A Throttle Position Sensor (TPS) is a sensor used to monitor the position of the throttle in an internal combustion engine. The sensor is usually located on the butterfly spindle so that it can directly monitor the position of the butterfly throttle valve.
The sensor is usually a potentiometer and therefore provides a variable resistance dependent upon the position of the butterfly valve (and hence throttle position).
The sensor signal is used by the Engine Control Unit (ECU) as an input to its control system. The ignition timing and fuel injection timing (and potentially other parameters) are altered depending upon the position of the throttle, and also depending on the rate of change of that position. For example, in fuel injected engines, in order to avoid stalling, extra fuel may be injected if the throttle is opened rapidly (mimicking the accelerator pump of carburetor systems).