What to consider before changing your spark plugs

The recommended replacement interval for standard spark plugs has typically been every 40,000 to 55,000 kilometres. But most of extended life plugs have special wear-resistant electrodes made of platinum, iridium, nickel yttrium or other exotic alloys that minimise electrode erosion. Such plugs can usually go 140,000 kilometres plus with little or no electrode wear. Even so, they may still be vulnerable to fouling if an engine has an oil consumption problem or spends excessive amounts of time idling.

Extended life spark plugs are a good upgrade for many engines, but may not be the best choice for an older engine that uses oil or even some performance engines.

According to one plug manufacturer, platinum-tipped electrodes run hotter than standard electrodes. This may increase the risk of pre-ignition and detonation in some turbocharged and high-performance engines. For such applications, a standard plug with a colder heat range might be a safer choice.

There are also a wide variety of electrode configurations from which to choose today. Each manufacturer claims certain performance benefits for their particular design. It may be reduced electrode wear or improved ignition reliability, or both. Such plugs are often marketed as “premium” or “performance” plugs, and may command a price which is quite different from the usual price. Some of these plugs (as well as standard plugs) also have multiple electrodes (two, three or four ground electrodes).

A spark plug with more than one ground electrode will still only produce one spark per ignition cycle. But with four paths from which to choose, the likelihood of getting a good spark to, at least, one of the ground electrodes is multiplied for improved ignition reliability. Having more than one ground electrode also distributes the wear to minimise electrode erosion and growth of the spark gap over time. Such plugs also experience a self-cleaning effect because the sideways path of the spark helps burn deposits off of the insulator.

Are premium plugs worth the extra money?

They are if they can provide extended plug life; reduce the need for maintenance or improve overall ignition performance. The plugs in many front-wheel drive cars and minivans with V6 engines are very difficult to replace. Installing extended life plugs can almost eliminate the plug change hassle for good. Likewise, performance plugs that reduce misfires can enhance performance for a smoother running, cleaner, more fuel efficient engine. No spark plug can create power out of thin air, but improved ignition reliability can minimise any horsepower loss due to misfire.

What to do before changing spark plugs

When changing spark plugs, wait until the engine has cooled to remove the plugs. The engine should be at or near room temperature, and not hot to the touch. This is very important with aluminum cylinder heads because they reduce the risk of damaging the threads in the cylinder heads when the plugs come out (aluminum is a much softer metal than cast iron).

Most threads on spark plugs for engines with aluminum heads are either pre-coated to reduce the risk of thread damage, or the plug shell is made of a nickel alloy. If the plug shell is black or plain steel, however, you should put some anti-seize to the threads, and reduce the applied torque by about 30 to 40 per cent.

Do not use anti-seize if the plug shell is nickel or has been pre-coated. Anti-seize acts like a lubricant and may allow too much torque to be applied to the plugs, damaging the treads in the cylinder head.

NB: Parts of this piece were culled from the Internet.

Feedback

I bought a 2007 BMW X5 from the United States in 2016 myself and confirmed from Carfax that it was in very good shape. I used it in Nigeria only in December 2016. In January 2017, I travelled back to my base in Abidjan, Côte d’Ivoire. I visited Nigeria only four times in 2017. In April, the car fuel pump was changed following a diagnosis run by my mechanic. I travelled to Ado Ekiti in May and on the way back, I noticed the same issue that warranted changing the fuel pump. I parked the car, travelled back to base and came back in November. Before my arrival, I instructed the mechanic to pick the car and service it and fix whatever issue. He changed plugs and ignition coil and everything seemed cool.

Coming home in December, I realised one of the water line connectors leading to the engine was damaged. I didn’t know how this happened; that was fixed again. I then planned a trip to Ibadan and before getting to Mowe, I realised the car wasn’t moving well. At some point, the car would refuse to move at all. I managed to turn back and cut short the trip.

Another computerised diagnosis by my mechanic showed that the water pump should be changed. We changed the water pump and the next day, the issue started again. We changed the thermostat, still same status. I have parked the car and am looking for advice. Please, let me know if there is anything you can advise me to do. Thank you.

—Abiodun Aina

I think whoever is doing the diagnosis is going about it the wrong way. Yes, the water pump will trigger a code on the powertrain system, but it could also be an electrical fault that is causing the code to be triggered. I will want you to please forward all the codes from the scan results to me for proper analysis.

Diagnostic codes

P0367: Camshaft Position Sensor ‘B’ Circuit Low Bank 1

The Camshaft Position Sensor is an electronic device used in an engine to record the rate at which the camshaft is spinning. This information is used by the Engine Control Module (ECM) to control ignition and fuel injection. The camshaft position sensor senses the retraction of camshaft (intake) to identify a particular cylinder. The camshaft position sensor senses the piston position. The sensor system consists of a rotating part, typically a disc, as well as a static part, the actual sensor.

When the engine is running, the high and low parts of the teeth cause the gap with the sensor to change. The changing gap causes the magnetic field near the sensor to change. The change in the magnetic field causes the voltage from the sensor to change. When the crankshaft position sensor (POS) system becomes inoperative, the camshaft position sensor provides various controls of engine parts instead, utilising timing of cylinder identification signals.

The code is detected when the camshaft position sensor signal sent to the ECM is too low.

Possible symptoms: Engine light on (or Service Engine Soon Warning Light), lack/loss of power engine stall.

Possible causes: Faulty Camshaft Position Sensor, Camshaft Position Sensor harness is open or shorted, Camshaft Position Sensor circuit poor electrical connection, faulty starter motor, starting system circuit, dead (weak) battery.

P0368: Camshaft Position Sensor ‘B’ Circuit High Bank1

The Camshaft Position Sensor is an electronic device used in an engine to record the rate at which the camshaft is spinning. This information is used by the ECM to control ignition and fuel injection. The camshaft position sensor senses the retraction of camshaft (intake) to identify a particular cylinder. The camshaft position sensor senses the piston position. The sensor system consists of a rotating part, typically a disc, as well as a static part, the actual sensor.

When the engine is running, the high and low parts of the teeth cause the gap with the sensor to change. The changing gap causes the magnetic field near the sensor to change. The change in the magnetic field causes the voltage from the sensor to change. When the crankshaft POS system becomes inoperative, the camshaft position sensor provides various controls of engine parts instead, utilising timing of cylinder identification signals.

The code is detected when the camshaft position sensor signal sent to the ECM is too high.

Possible symptoms: Engine light on (or Service Engine Soon Warning Light), lack/loss of power engine stall.

P0369: Camshaft Position Sensor ‘B’ Circuit Intermittent Bank 1

When the engine is running, the high and low parts of the teeth cause the gap with the sensor to change. The changing gap causes the magnetic field near the sensor to change. The change in the magnetic field causes the voltage from the sensor to change. When the crankshaft POS system becomes inoperative, the camshaft position sensor provides various controls of engine parts instead, utilising timing of cylinder identification signals.

The code is detected when the camshaft position sensor signal sent to the ECM is intermittent.

Possible symptoms: Engine light on (or Service Engine Soon Warning Light), lack/loss of power engine stall.

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