In appearance, glow plugs are similar to the spark plugs of a gasoline engine, but they do not produce a spark. Used to start a diesel engine. They consist of a body, a tip and a heating element (metal or ceramic) - a spiral. The maximum tip temperature is 1350 degrees Celsius. The tip of a glow plug in a diesel engine consists of a pair of spirals - heating and regulating. The latter provides the spark plug with protection from overheating by increasing electrical resistance as the temperature rises. The heating coil provides heating of the combustible mixture and air.
There are two main types of glow plugs:
- pin - with a metal heating element, which is an alloy of iron, chromium and nickel. The inside of the case is filled with magnesium oxide;
- ceramic - the heating element is made of ceramic, which has increased resistance to temperature changes. The material for the manufacture of the protective shell is silicone nitrite.
Ceramic spark plugs heat up the fuel in just 2 seconds. Their use allows you to start a diesel engine without preheating.
Distinctive features include the resistance of the candle. It ranges from 0.5 to 1.8 ohms. Moreover, metal always has greater resistance than ceramics. Thus, while ceramics lose in resistance, they gain in the ability to use more powerful currents for heating.
Where is the glow plug relay located?
A relay is an electrical device. That is why testing its operation in practice will not be very difficult. A multimeter will help simplify the test.
Initially, the relay will need to be detected. It is usually made as a block or box of a separate design. The fasteners are made directly to the car body. The place for such fasteners is usually called “mass”.
Power from the negative terminal is provided directly through this connection. Each of the remaining ends comes with a plus sign.
- The block provided in the design, which provides control of the engine system, provides additional data to the relay device.
- The block part processes information received from temperature sensors.
- At the same time, it generates the necessary pulse signal supplied to the input of the relay device.
- Thus, both the process of closing the circuit and its opening are ensured.
- This indicates that in addition to the relay device a package with wires is connected.
So, by looking at the wires that come out of the glow plugs, you can quite easily detect such a device.
Glow plug in a diesel engine of a modern car
The glow plug in a diesel engine is capable of heating the injection zone to 1000°C in a matter of seconds. When the diesel engine is turned on, these devices operate until the coolant temperature reaches plus 75°C. These structures can be made of either closed ceramics or open metal. The heating element is made in the form of a spiral.
Metal pin structures have spirals: heating and adjustment. Thanks to the first, rapid heating occurs, the second serves to protect the structure from overheating.
The composition of ceramic parts is more complex: Metal body.
Skoda Octavia FL › Logbook › Causes and Symptoms of faulty spark plugs and ignition coils
The topic is already as old as the hills and has been discussed a hundred times, and yet I decided to look into it in more detail (I warn you in advance there will be a lot of letters))) Sign: when accelerating from 2000 rpm into 4-5-6 gears, the car began to jerk (later it began to blink check engine), well, everything is clear, either the spark plugs or the coil, but still, why is this happening? I had NGK spark plugs, original number 06H905601A, look at ETKA for replacement Bosch F5KPP332SBN 06H 905 611 0.7+0.1 mm Bosch F5KPP332SBB 101 905 631 H 0.8-0.1 mm NGK PFR7S8EG 06H 905 601 A 0.8- 0.1 mm Bosch F6KPP332S 101 905 631 B 0.8-0.1 mm Bosch - I won’t consider it because
There is no information on candles on the official website at all! What the manufacturer NGK Spark Plug Europe writes to us about PFR7S8EG spark plugs!
How does the glow plug relay work?
The closure, as well as the opening of sections of the electrical circuit, occurs thanks to a separate relay device. Moreover, this happens depending on how the value changes, which must be constantly monitored.
In this particular case, for a certain period of time, the relay device supplies current to the glow plugs. Then allow the candles to cool slightly, ensuring that the current supply is cut off.
- Based on this, we can draw a logical conclusion that the occurrence of a malfunction in a particular relay leads to a stop in the operation of the glow plugs.
- Fuel that has failed to reach the temperature required for combustion will have little effect.
- This in turn leads to significant power losses, along with greater fuel consumption than expected.
Therefore, the performance of such a device decides a lot, and if a question arises about its serviceability or malfunction, then a check must be carried out immediately.
Diagnostics and replacement of glow plug relays
To check the relay device, you need to switch the multimeter to read the voltage value. Now you have to turn on the ignition and take appropriate measurements at the output of the device.
- In this case, one probe is applied close to those terminals that are intended for spark plugs. At the same time as the first one, the second one is also tightly applied to the car body. In this case, the output voltage value should be equal to twelve volts or higher.
- Another way could be to conduct the voltage value at the battery terminals. If twelve or more volts are received here, whereas on the relay it is, for example, only eleven volts, the relay device is defined as faulty.
Another verification method, which is often used in practice, is called the indirect verification method. To do this, you will need to unscrew the spark plugs. Then the wires that come from the relay device are connected to their ends, after which the ignition system must be turned on.
The device is operational when heat begins to flow from the candles. In the opposite case, the fault will lie either in the spark plugs or in the relay device itself.
The relay is replaced as follows:
- First of all, the wires that connect the electronic control unit with the glow plugs are removed from it;
- After which you have to unscrew the fastening;
- The place where the “mass” of the new device connects to the car body is thoroughly cleaned;
- A new relay is installed.
