Device for determining the short circuit. Automotive Diagnostic Toolkit

11.11.2009

"Toolkit for Automotive Diagnostics"

Car diagnostics, troubleshooting, and its further elimination is impossible without the presence of "brains".

Namely "brains", and not stolen other people's thoughts from this or that technical forum.

I will not lie, it was time, I did a little analysis and it turned out that an average Russian city with a population of about 100 thousand people has about five "real car diagnostics". “Real” are those who “have brains, can think and think”.

All the others working in this area are "one-day diagnosticians", "kosyachniki", "diagnosticians - thieves of other people's thoughts" and the like.

And you don't have to go far for examples - just look around. Listen to your neighbor, his mates - rewinds after returning from some car service ...

For an automotive Diagnostician, “having brains” means possession and development of a set of practical methods and techniques for expediently carrying out work to identify and eliminate a malfunction in a car.

It has been said long, but true.

And when these very "practical methods and techniques" are simply stolen, and thoughtlessly, without analysis and the desire to continue and increase them, then we get what we get. As, for example, in the cases described below ...

Toyota Ipsum car.

The engine is simple: 3S-FE. The machine is old, but reliable. But each unit has its own term - this is how the owner of the car thought when it began to throw out the pretzel: sometimes it refused to start, it worked unstably at idle speed, like "Troilus", and sometimes it could even stall.

And do you know how many garages and garages this car passed in the hope of being repaired? Very, very much. And it was not somewhere on the periphery, but in the capital of our Motherland - the city of Moscow.

As the fish rots from the head, so the mass of half-educated people, "shoals" and "diagnosticians - thieves" is concentrated in this very "capital".

As the owner of the car calculated, during the "troubleshooting" he gave all these "car services" about 100,000 rubles.

And I specially wrote the word "Car service" in quotation marks, well, a normal organization cannot be called a "service", especially "auto".

A more accurate name immediately creeps into the language: "Auto-Service of painless taking money from the population" or "Cash auto-vacuum cleaner".

The employees of such "services" do not have technical brains, they only have a desire to make money. Lie, deceive the Client, rip off money from him and grin after ...

The last straw in a series of unsuccessful repairs was the repair in the city of Vladimir. There the car again began to "troit", then stalled, then wound up and somehow limped to the local "car service".

No problem !, - the Client was assured, - we will do it quickly, reliably, with a guarantee.

And they asked:

Where are you from? From Moscow? Well, then with a double guarantee.

Subtext: "And the hell you're going to trudge to us for 200 km" ...

How much did the “troubleshooting” cost? Well, absolutely "little things", quite a bit compared to previous repairs - "only" 6.000 rubles. But "with a guarantee" -☺ )

... and mats - rewinds in a long fancy train followed the car along the highway ..., -☺

He got a phone or an acquaintance told him - it doesn't matter, the main thing is that the next day he ended up in the auto repair shop with Mikhail Evgenievich (his coordinates are at the end of the article, nickname on the forum "Legion-Avtodata - AVTEL").

Above, we touched on such a word as "technique". Tell me, how would you start looking for such a malfunction?

Are there any trouble codes?

There is. One in memory. Common (Fault Area): DTC 14 (Ignition Signal)

Spinning with a starter? What for? If we turn it with a starter, we will “put” the battery, and pour fuel into the cylinders, which will then go into the crankcase and the gasoline will become “semi-gasoline”.

Why, when there is a great program:

Program "58-X Generator" is intended for emulation of DPKV signals received from the master disk of the car (configuration 60-2).

Opportunities:

-The DPKV signal is generated at the output of any COM port ("TXD" 3rd leg of 9-pin COM; 5-leg "ground").

-The program allows you to change the frequency of the DPKV signal to emulate the wheel rotation speed from 60 to 9000 RPM (approximately).

-Possibility of forming an additional skip of teeth to check the anti-theft function (anti-theft function is created by the CombiLoader from SMS-Software).

Developer: Alexey Mikheenkov (C) SMS-Software

The program on the Internet is distributed free of charge.

Here is its appearance:

And here's how it connects and emulates:

A spark gap is placed on the ignition coils, the injectors are turned off, the program is started and the "quality and presence of a spark" appears. Convenient: the engine does not work, the battery is not discharged by dozens of starts, “look for a malfunction as much as you like ...

But the spark was wonderful!

So what's the deal?

Many manuals and reference books describe such a troubleshooting method as “wiggling harnesses, connectors and loops”.

Moved. First in one place, then in another. And I found it.

That is, first I determined the “area of ​​failure”, and then began to narrow it down and came to the true reason, here it is, in the bottom photo:

Guess what is the reason? The malfunction is the simplest. But in Moscow, it turns out, it costs about 100,000 rubles to find it and to “eliminate” it. ... However, perhaps, not only in Moscow?

Once the engine was dismantled, and when they began to assemble it, the "mass" of the ignition coils was screwed on badly. Like "made money". Over time, she loosened up and ... "we have what we have."

The client has left. Thanks. I was surprised. And he promised to go to Vladimir "to figure it out."

And the next day the Client called again.

No, not because of yesterday's malfunction. Here the "theory of improbabilities" has already played a role - a new malfunction, another: a light on the instrument panel came on, signaling a generator malfunction.

Well, a generator is like a generator.

And it even charges about 14 volts.

However, the malfunction is still present, since the fuse in the fuse box constantly burns out (photo on the right).

You don't need to invent anything. To find faults in the electrical circuits of a car, many devices have long been invented, for example:

A device for finding faults in the electrical circuits of the car

Set FF310 designed to detect and localize breaks and short circuits in the electrical circuits of the vehicle. The set includes FF310 includes a miniature transmitter and receiver. The transmitter connects to a faulty electrical circuit and generates a high frequency signal. A flexible probe receiver is used to locate open or short circuits. This is accomplished by moving the probe along the wire harness. The receiver identifies the type of malfunction (open or short circuit), which is indicated by light and sound indicators. The versatility of the design allows the device to be used on any cars and motorcycles with an on-board voltage from 6 to 24 volts. Without any restrictions, the device can also be used on future vehicles with a 42 Volt on-board network.

The kit is supplied in a convenient plastic case, which, in addition to the mentioned items, also includes a special piercing probe and a set of connectors for connecting the transmitter to various types of fuse sockets.

Have you read it? This device was used. What, it turned out, look at the photo on the right: this is the so-called "burnout". Hence the fuse "flew" constantly. And the light on the instrument panel was on, signaling a malfunction. It took a little time to fix the problem.

What's the bottom line?

Both the first and the second malfunctions were of the "not very difficult" category.

And they could be found without the use of the specified "adapt"?

It could be.

But let's take the time factor into account.

Using certain "tweaks" AutoDiagnostics can significantly reduce the time for troubleshooting.

And time, as you know, is money.

And now you can try to summarize everything by the title of the article:

"Toolkit for autodiagnostics". So what is required for this:

1. Human + Light Soul. All other colors are not suitable for those who have chosen the specialty AUTOMOTIVE DIAGNOSTICS as their profession.

2. Ability to analyze situations, structure your accumulated experience and fuse the experience of colleagues into it

3. Internet: 10 years ago, it was still in its infancy, now it is starting to grow, and in 10 years it will be impossible for a car diagnostician to work without it

4. Critical self-assessment: always remember that the time of Geniuses has passed and nothing can be discovered in autodiagnostics, you can only skillfully use the proposed technical and theoretical tools

But that's not all.

It is impossible to list “everything”.

Can add. Add in the topic where there is a discussion of this material.

Surely every car diagnostician has something of his own ...

I dealt with the faults in this article

Kudryavtsev Mikhail Evgenievich

Discussion on our forum:

You will find information on car maintenance and repair in the book (s):

People who often deal with engines will find this device very useful. It is very simple in design and application. Using this device, you can check the windings of transformers, chokes, electric motors, relays, magnetic starters, contactors and other coils with inductance from 200 μH to 2 H. It is possible to determine not only the integrity of the winding, but also the presence of an interturn short circuit in it. The figure shows a diagram of the device:

(click on the image to enlarge)

The basis of the device is a measuring generator on transistors VT1, VT2. Its operating frequency is determined by the parameters of the oscillatory circuit formed by the capacitor C1 and the tested inductance coil, to the terminals of which the XP1 and XP2 probes are connected. The variable resistor R1 is used to set the required depth of positive feedback, which ensures reliable operation of the generator.

Transistor VT3, operating in diode mode, creates the necessary voltage level shift between the emitter of the transistor VT2 and the base VT4.

A pulse generator is assembled on transistors VT4, VT5, which, together with a power amplifier on a transistor VT6, ensures the operation of the HL1 LED in one of three modes: absence of glow, blinking and continuous combustion. The mode of operation of the pulse generator is determined by the bias voltage based on the transistor VT4.

The device works as follows. When the probes XP1 and XP2 are closed, the measuring generator is not excited, the transistor VT2 is open. The constant voltage at its emitter, and therefore, based on the VT4 transistor, is not enough to start the pulse generator. At the same time, the transistors VT5, VT6 are open, and the diode burns continuously, signaling the integrity of the tested circuit.

When a serviceable inductance coil, say, a motor winding is connected to the instrument's probes, and the motor of the variable resistor R1 is set to a certain position, the measuring generator is excited. The voltage at the emitter of the transistor VT2 increases, which leads to an increase in the bias voltage at the base of the transistor VT4 and the start of the pulse generator. The diode starts blinking.

If there are short-circuited turns in the tested winding, the measuring generator is not excited and the probe works as with closed probes (the diode just glows).

With open probes or open circuit of the tested coil, the transistor VT2 is closed. The voltage at its emitter, and therefore on the base of the VT4 transistor, increases sharply. This transistor opens to saturation, and the oscillations of the pulse generator are disrupted. Transistors VT5, VT6 close, the diode HL1 does not light up.

In addition to those indicated in the diagram, transistors VT1 - VT3 can be KT315G, KT358V, KT312V. Transistors KT361B can be replaced with any of the KT502, KT361 series. It is advisable to use the VT6 transistor of the KT315, KT503 series with any letter index. Permanent resistors - MLT-0.125; capacitor C1 - KM; C2 and SZ - K50-6; LED AL310A, AL 307A, AL307B, a 68 Ohm resistor must be sequentially included in the circuit; power supply - 3V (conventional batteries or crown).

It may happen that in the extreme right position of the resistor slider and when the probe probes are open, the diode will glow. Then you will have to pick up the resistor R3 (increase its resistance) so that the diode goes out.

When checking the coils of small inductance, the sharpness of the "tuning" of the variable resistor may turn out to be excessive. It is not difficult to get out of the position by connecting in series with the resistor R1 another variable resistor with a low resistance, or using a resistance box or a set of resistors instead of a variable resistor, connected by a small-sized multi-position switch (roughly, smoothly). Information taken from the magazine "Radio" No. 7 for 1990.

And this is how I made it:

Who is interested, write, there is a seal in the Sprint-Layout format

In the video, I demonstrated it in operation, knowingly took a non-working engine.

One of the common reasons due to which there are problems with electrical devices is damage to the cable in a certain section of the wiring. It is good when the place of the cable break is known and it is available for quick repair. But what if an open or short circuit occurred in a closed section of the circuit, somewhere in the grooves? In this case, it is necessary either to call a professional electrician for troubleshooting, or to look for the break point yourself. And if you decide to read this article, then you probably chose the second option.

Short circuit in hidden wiring

We are looking for closure sites

Before looking for a break in hidden wiring, it is worth making sure that there is voltage at the input, and the machines are in good order. If, when examining the machines, it was determined that the plugs are in the cocked state, then an emergency occurred in the house itself, if the machine is in the off position, then this indicates a short circuit that has occurred. Then you can proceed to the direct search for the site where the failure occurred.

As a rule, the wiring in the house is installed according to the ray principle. In other words, beams (wiring) radiate from the dose box to the sockets, and a separate cable is connected to each switch. We recommend that you familiarize yourself with the wiring diagram that is installed in your home - this will greatly simplify the search for an open or short circuit in the circuit.

Find a dose box and open it - there are several twists inside. It is recommended to measure resistance and voltage on each line. If the indicators are positive everywhere, you need to look for the cause in another dose box. As soon as you find a twist on which there is no voltage and resistance, this means that an open circuit has occurred on this line, which must be eliminated.

We are looking for short circuits in hidden wiring

So, we have identified the common area where the gap occurred. Now you need to find out in which specific place the gap occurred, and then eliminate it. Consider how to find a break in a hidden wiring.

Finding the place of the cliff

The first and most simple method of further action is to open the plaster and find a wire that is not energized. An autopsy is performed from the junction box and further to the place of damage. A large opened section of a groove on the wall, dust and noise - all this in order to find and eliminate an area of ​​several centimeters in size.

Note that in some cases, it is even difficult to determine the route of the cable that runs through the wall. It is good if electricians used GOSTs and wiring rules when laying the cable, but there are often cases when cables are laid in the shortest way to reduce costs. In this case, it may be necessary to remove all plaster from the wall in order to define the route and eliminate the defect. In order to avoid such destructive repairs, electricians use a special device to detect hidden wiring breaks.

Professionals most often use the MS-58M device - a special non-contact probe for determining the voltage on the track through various materials, incl. concrete, brick, wood, etc.

MS-58M instrument

For everyday purposes, simple variations of the combined type, such as the MS-48NS, are also used. With the help of this device, you can determine the voltage at a certain section of the conductor, ring the wire, and also determine the section of the route where the voltage disappears.

MS-48NS instrument

As a rule, such devices accurately determine the breakage point - up to 8-12 cm. Thus, the amount of work is significantly reduced and the cable can be repaired without significant damage.