Below are all the ways to check the glow plugs on a diesel engine. When choosing a suitable option, you should focus on a number of criteria - skills, availability of devices, free time and tools. Ideally, all methods can be used and additional inspection done.
Start by measuring the voltage at the inputs of the glow plugs. Often the malfunction is caused by a trivial reason - the oxidation of the contact group or the weakening of one or another terminal through which power is supplied. For such a check, you will need a multimeter (with the ability to measure voltage and resistance) or a 12 Volt light bulb (if the device was not nearby).
If you do not remove the glow plugs from the engine, then the check will be uninformative and inaccurate, because you will not be able to see the glow activity. Exceptions are some types of motors, in which you can unscrew the nozzles and assess the condition of the heating elements through the wells.
To get accurate data, it is recommended to unscrew the candles and check them on the battery, and measure the voltage and resistance parameters using a multimeter.
The simplest way to check the glow plugs after unscrewing the parts is to use a 12 volt warning light. Here the sequence of actions is as follows:
If the light is on, it means that the heating element is intact, and there is no breakage in it. If the lamp does not burn, or its light is too dim, then the glow plug is out of order and requires replacement. It should be noted that checking glow plugs using a light bulb is hardly a reliable method. Therefore, it is better to use a more advanced diagnostic method involving the use of a multimeter.
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VIDEO
This technique is similar to the previous method, with the difference that there is no need for a light bulb. The task of the car owner is to determine the fact of the appearance of a spark, with an active touch of the threaded part. Such a check is permissible only on old diesel engines where the electronic control unit is not installed.
How to check glow plugs for a spark - the algorithm is as follows:
Prepare a piece of wire, about 1 m long, and strip it on both sides.
Move the spark plugs away from the bus that is energized.
Connect the wire with one side to the positive of the battery and the other to the center electrode.
If the glow plug is in good working order, then, at the moment of touching, you can notice the appearance of a strong spark. If there is a defect in the heating element, there will be little or no sparking.
Because of the dangers of this technique, it is not used on modern machines. But knowledge of its features will allow you to avoid fatal errors in the process of checking the integrity of the glow plugs using a test lamp.
When all the glow plug checks have been completed and they have shown that the heating elements are working properly, you can reinstall the parts. But what if they don't work on the engine? The reason may be hidden in the electrical wiring. The first things to check are fuses, glow plug relays, and sensors.
It is better to entrust the monitoring of the health of sensors and time relays to the masters. At the same time, remember that heating in the combustion chamber is turned on only on a cold engine, the temperature of which is below 60 degrees Celsius.
The task of the glow plug relay is to activate the heating elements prior to starting the engine. Turning on the device can be determined by the presence of a click that occurs after turning the key in the ignition lock. The command about the need for activation is given by the ECU, and the relay simply executes the "order" and activates the system. The control unit, in turn, takes information from the crankshaft and coolant sensors. Thanks to the commands given from the unit, the circuit is closed or opened.
Checking the glow plug relay must be done, in the absence of the clicks mentioned above. If the light bulb with a spiral stops lighting up, pay attention to inspecting the fuses, and then check the temperature sensor.
Each relay has several groups of contacts. One-piece devices have four, while two-piece devices have eight. Two control contacts and two - windings. After the signal is given, the control contacts are triggered. It should be noted that there is no common name for the contacts of different machines. They can be different for each relay.
Generally speaking, on diesel cars, the winding contacts are signed with numbers 86 and 85, and the control contacts are 30 and 87. When voltage is applied to contacts 30 and 87, the winding contacts should close. To check, to terminals 86 and 87, connect a light bulb and energize the glow plug relay. If the lamp is on, we can talk about the serviceability of the relay. If this does not happen, most likely, the coil has burned out.
The health of the relay of the heating elements, like the candles themselves, can be checked with a multimeter by measuring the resistance.If the device is silent when connected, the coil can be changed.
Knowing how to check glow plugs, you can easily solve any problem that has arisen and diagnose a breakdown, without the involvement of specialists. To carry out the check, no complicated equipment is needed - a light bulb, a battery and a multimeter are enough.
The circuit was made temporarily, from what was at hand, but the operating time showed that nothing else was needed, I had long forgotten about replacing the glow plugs. Only the block itself was altered, and the terminals that are not used were also removed from it. The block is interchangeable with the factory one. (no changes were made to the car's electrical circuit)
At first I thought about doing it without a relay (that's why there is a powerful KT837F transistor on the diagram), but then I insured myself - I decided to put a relay to switch the load to make it more reliable.
When the key is turned in the ignition switch to the “on” position, + 12V is supplied to terminal 86 of the block. Capacitor C1 is discharged, the voltage at the anode of the Zener diode is lower than the stabilization voltage (6.8V), the Zener diode is closed and the transistor VT1 is closed. A negative potential is supplied to the base of the transistor VT2 through R6 and the transistor VT2 opens. The relay is triggered and the relay contacts switch the relay coil of the glow plugs and the preheating warning lamp with minus (ground) of the car. The glow plug relay (not shown) turns on the engine glow plugs.
The engine temperature sensor when the engine is cold (20 ° C) has a resistance of about 1.2kΩ. at 60 degrees. C resistance is about 280 Ohms. The higher the engine temperature, the lower the resistance of the temperature sensor, and vice versa, the colder the engine, the greater the resistance of the sensor. A temperature sensor (not shown in the diagram) is connected in parallel with resistor R3. The charge time of the capacitor C1 depends on the resistance of the sensor. The capacitor is charged through the + 12V circuit, R4, in parallel with R3 / temperature sensor, -12V. Gradually, the capacitor is charged when the voltage on the negative plate reaches the breakdown voltage of the Zener diode VD2, the transistor VT1 opens and VT2 closes. The relay will release the contacts, the glow plugs and warning light will turn off.
The ignition key can now be turned to the position that engages the engine starter. When the starter is switched on via the ignition switch, the plus is connected to terminal 50. Capacitor C1 begins to discharge through the ignition switch, diode VD1, R1. The voltage across the capacitor drops, the Zener diode VD2 and the transistor VT1 close and the transistor VT2 opens. The relay energizes, the glow plugs and warning light come on. When the engine starts and the ignition key is moved back to the previous position, terminal 50 is de-energized, the capacitor is gradually charged and after a short time delay, the transistor VT1 will open and VT2 will close, the relay will release the contacts - the glow plugs will turn off and the preheating warning lamp will go out.
Resistor R2 serves to discharge capacitor C1 on power off when the motor is not running. Resistor R3 maintains the capacitor in a charged state when the temperature sensor circuit is open and protects the glow plugs from false switching.
The circuit is suitable for many cars, the only condition is, based on the resistance of the temperature sensor and the required heating time of the glow plugs, you need to recalculate the resistors of the charge / discharge circuit of the capacitor C1 and the capacitance C1
Glow plugs on diesel engines are often the “weak link” in freezing weather. The owners of such cars often have to give up planned trips because their engine stubbornly does not want to start. In this article, we will describe three easy ways to test diesel glow plugs.
Glow plugs play an important role when starting a diesel engine during the cold season. Thanks to their heating of the combustion chambers, it is possible to facilitate the ignition of the fuel in the engine cylinders.
The fastest way to check diesel glow plugs is shown in detail in the video at the end of the article.
Depending on the model and age of the car, there are different principles of operation of the diesel engine heating system:
In older cars, the glow plugs usually turn on almost every time the engine is started.
Modern cars can successfully start without turning on the glow plugs at freezing temperatures.
Therefore, before proceeding with the diagnosis of the diesel preheating system, you need to find out at what temperature the combustion chamber is heated. The glow plugs on the instrument panel are signaled by the corresponding light in the form of a spiral.
Failure of one or two glow plugs can be unnoticeable in relatively warm weather. And with the onset of frost, difficulties immediately arise with starting a diesel engine.
We will describe three different ways to test the functionality of a glow plug. The choice of each of them depends on whether the motorist has certain devices, tools, skills and free time.
The most accurate and visual picture of the health of heating elements for a diesel engine is given by checking on a storage battery. Each candle is checked separately, while the car enthusiast sees the degree of its glow.
The disadvantage of this diagnostic method will be the need to unscrew all the glow plugs. In some vehicles, this will require a significant investment of time, as well as the dismantling of some parts that impede access to the heating elements.
For testing, you will need an insulated wire about 0.5 m long.
The glow plug is turned upside down by the heating element and placed with the central electrode on the positive terminal of the battery.
Using an electric wire, you need to connect the negative terminal of the battery and the candle body (on the side).
If the heating element quickly becomes more than half-heated, then the spark plug is in good condition.
If there is no glow or only the tip of the element heats up, the plug needs to be replaced.
Below are simpler ways to test glow plugs.
Sometimes there is no time or tools to remove the glow plugs from the diesel head. In this case, a test with a multimeter may be helpful. The instrument is placed in the resistance test position (ohmmeter).
But first, it is necessary to disconnect from the glow plugs the wire that supplies current to the central electrode. A separate wire can be supplied to each heating element, or all candles can be connected with a copper or brass bus. Now it remains to connect the plus probe of the multimeter to the central electrode of the candle, and touch the negative probe to the side surface of the case. If the arrow does not deviate or there is no reading on the digital display, then there is a breakdown in the heating element. The glow plug must be replaced.
The disadvantage of this method is the difficulty in identifying heating elements with a weak glow. The tester will show that there is no breakdown, and the candle will not warm up the combustion chamber enough.
An old tried and tested method of checking glow plugs is sparking. To do this, you need an insulated wire 0.5-1 m long, at both ends of which 1-2 cm of insulation is removed.
Now you need to free the glow plugs from the bus and the supply wire. One end of the test wire is attached to the positive terminal of the battery, and the other end performs a tangential movement along the central electrode of the glow plug (look at the video below ). Thus, we can observe something like the following:
A strong spark is generated on a working heating element.
If the spark plug is weakly glowing, sparking will be negligible.
A completely faulty glow plug will have no spark at all.
This check can be safely done on old cars that do not have "brains" and a computer.In the video below, the glow plugs on a diesel Nissan Primera are checked in this way.
The above methods for checking the glow plugs allow you to independently detect the cause of a poor diesel start. If a faulty part is identified, the car owner will only have to replace the failed heating element. After that, starting the engine in cold weather, as a rule, is not difficult.
Also, for owners of cars with diesel engines in the winter season, it will not be superfluous to have an engine preheater.
VIDEO
The 260 and 60 patrols with RD28 and RD28T engines used a very sophisticated preheating system. This system consists of a timer, two relays, two candle bars (long and short) and six candles of two different types, three candles in a group.
In reality, I had to face the fact that, with the formal performance of each component of the system, everything refused to work together. As soon as the air temperature dropped below 15 degrees, starting the engine turned into sheer torment: tripping, smoke and the inability to work stably without gas filling until the engine warmed up. It was immediately clear that with an even greater decrease in temperature, the engine would simply stop starting.
Due to the high prices for original components, the excessive complexity of the factory system and the topic that caught my eye on the alteration of the heating system on the basis of one! relay from golf 2, somehow by itself came the desire to get rid of this hemorrhoids once and for all.
Briefly, the content of the rework looks like this:
Required spare parts:UPD. 2.1 The second option - candles with Hyundai oldrex NGK No. Y-722JS with two spirals and automatic adjustment of the operating temperature. The best option.
Dismantling:
Illustration of the location of the engine compartment components:
1. The first step is to remove the wire from the negative terminal of the battery. Safety comes first.
2. Then the short and long tires of the candles are unscrewed and six candles are unscrewed. The short bus bar and plugs can be stowed away, no longer required.
3. New candles are placed. They are a little higher than the original ones - that's okay. The candles are carefully twisted by hand until they stop and tightened with a force of 7-20N.
4. A long tire is lowered and screwed onto the candles.
5. Dismantle both spark plug relays. Each relay has a separate harness. We carefully insulate a bundle of 4 wires: it is no longer needed. From the second harness, you will need a thick black wire - mass, a thick white-red wire - + 12V from the battery and a thick green-red wire - to the candle bus. We insulate the rest of the wires.
Installation:
1. Turn off the glow control unit. To do this, remove the decorative panel under the steering wheel. The control unit is located directly above the steering column. Marked with an arrow in the figure.
2. We take out the block from the block. It is required to pull out two wires from it. From terminal 14 (yellow-green) to the control lamp and terminal 3 (brown) to turn on the ignition.
3. These wires must be brought out to the engine compartment. To do this, use the purchased wire, any mounting means and technological holes in the motor panel. Everyone chooses the way of withdrawal himself. The wires must be laid to the place where the relay is to be installed.
4. We stretch the wire from the temperature sensor. The sensor is two-pin, the second pin is shorted to ground.
5.We stretch the wire from the control contact of the starter retractor relay. It receives a signal when the key is turned to start. It is required for the heating relay control circuit.
6. Install a new relay. We connect the wires. The relay has seven terminals in total, as shown in the figure.
- 30 - + 12V from the battery.
In more detail, the principle of operation of the glow relay is described here.
Everything. You can use it. The car now starts confidently without refueling and manual gas. The clouds of smoke and the wild vibration of the internal combustion engine before warming up disappeared. It should be noted separately that the new heating system is radically cheaper than the original one. Which is very, very nice.
Cars change, friends and the forum remain. [my.housecope.com/wp-content/uploads/ext/1209]
Sprinter W901-W905. Engine. General questions ⇒ Glow plugs - how to unscrew correctly so as not to bummer
Message racer MB »25 Dec 2012, 19:39
Message Vladimir76region »25 Dec 2012, 20:16
Message SLy »25 Dec 2012, 20:26
Message racer MB 26 Dec 2012, 02:24
Message denya1 »26 Dec 2012, 19:00
Message racer MB 26 Dec 2012, 19:11
Message SLy 26 Dec 2012, 19:39
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Message SLy Dec 29, 2012 7:21 pm
The point then is to smear them in general, there is a thermal gap, be healthy, and if the landing gas passes through and no paste will save, even if it is a Mercedes company, but even a bugatti
In short, the meaning is this, smear, do not smear, but would not let the landing pass, and the thread was driven away and there will be no grief when replacing
How to unscrew a broken glow plug? If a person has such a question, and he began to look for information on this topic, then it makes sense to figure out what is not worth doing. After all, not all advice is useful. Most often, you can read about dissolving a candle in acid. It's hard to come up with more nonsense. Please note that the screwed part of the spark plug, like the engine, is made of metal. Yes, the skirt of a glow plug is made of soft metal, but a concentrated acid solution is required to dissolve it. Using it, you are guaranteed to damage the cylinder head. That is, using this advice, you will definitely get to replace the cylinder head, moreover, this is at best.
There are 2 ways to fix this problem:
Complete disassembly of the engine;
Unscrewing the remainder of the candle using a special tool.
The first method requires quite serious knowledge and skills in repairing motors, in addition to this, it is laborious. The second method seems easy at first glance, but in practice it is also quite complicated, for this you will need to acquire a tool and learn to work with it correctly.
To dismantle a candle, you will need a whole set of tools that are not always available in the garage. This includes:
Here is such a rather large list you will need to prepare before starting the repair.
After you have managed to unscrew the candle, you will need to check the threads in the well. It must be free from damage and burrs. In principle, if you did everything carefully, then there should be no problems. Do not forget to blow out the cylinder from dust and small particles formed during the unscrewing process. When installing the replacement part, be sure to use a torque wrench and tighten it to the manufacturer's recommended torque.
Video (click to play).
Conclusion ... The problem with a broken-off glow plug on a diesel engine is not such a rare thing. Therefore, many would be interested to know how to unscrew a broken glow plug. In fact, if you have straight arms, you can do this without any problems. Although, in any case, you will have to tinker, nevertheless the engine requires special attention. To work, you will need to purchase special keys.
