In their daily workshop practice, mechanics face many challenges in diagnosing vehicle starting problems. Imagine a situation in which a customer reports that his car is not starting. After finding the battery worn out and replacing it with a new one, the customer comes back with the same problem. What to replace next? How about the starter? It is at such moments that an oscilloscope can become an invaluable tool that not only reduces the time of diagnosis, but also minimizes costs and emphasizes your professionalism. In this article you will learn how measuring the starter with an oscilloscope can improve your daily work.
Oscilloscope is an advanced diagnostic device that allows you to visualize electrical signals over time. With this tool you can observe changes in voltage and current in electronic circuits. But oscilloscopes are tools not only for electronics engineers. Based on the measurement of current and voltage, we can easily check the overall condition of the starter system.
The advantage that an oscilloscope gives is based on the acquisition of more signal details than a typical multimeter offers. By observing the exact voltage and current waveforms flowing during engine startup, we can tell a lot about the condition of the engine.
From the point of view of diagnostics, simultaneous measurement of starter voltage and current provides the most data. To do this, we need a device with at least two channels. If you have an oscilloscope that has only one channel, we can perform the test in two stages.
As such, the oscilloscope records the voltage and its changes. The voltage drop is the result of current flowing through a resistance, so it applies to the battery, the starter wire, its contactor, the ground connection and all the connections in the starter itself. The battery voltage itself during engine start provides a lot of valuable information. An excessive drop in voltage in most cases indicates a worn battery, but it can also be the result of an abnormality within the starter’s starter.
The starter current when the engine is started is usually several hundred amperes. In order for such a measurement to be made by an oscilloscope, we need to equip it with current clamps with an appropriate range. They act as a transducer, converting the current into a voltage signal applied to a given input channel. Based on the current waveform, we can more easily distinguish between a fault involving the starter and the impact of a worn battery.
The current signal can also be used to determine the compression (compression pressure) of an engine. This is the so-called indirect method of testing compression pressure. With its help, we will not determine the exact value of compression in units of pressure, but we will know the interrelationship between cylinders expressed in percentages. This method is supported by many automotive oscilloscopes.
The DBT-12+ tester is also worth considering as an alternative to the typical oscilloscope measurement. The DBT-12+ is not only a battery tester, but additionally a tool for diagnosing starting and charging systems. Performing a typical battery test on a vehicle, we obtain, by the way, the waveform of engine starting and the voltage ripple generated by the alternator. In this way, we get to know the condition of key components of the vehicle’s electrical system in a matter of minutes.
Interpretation of osyloscope data is a key step in the diagnosis of starting problems. Below are the waveforms showing the correct engine start-up obtained by the DBT-12+ tester.
In many cases, excessive voltage drop accompanies battery wear. In some cases, a similar effect may be the result of a starter malfunction. When evaluating the voltage waveform, it is worthwhile to supplement it with current or perform a battery test.
There are also situations when the engine starts without much difficulty, but voltage measurements may indicate an imminent problem. Below we show the waveforms that accompany sparking associated with excessive wear of the starter brushes. If there is no response, the starter may eventually fail after several weeks.
The use of an oscilloscope in automotive diagnostics brings many benefits. First of all, it allows to improve the accuracy of diagnostics. Traditional methods are often based on assumptions and replacing more parts according to intuition. A mechanic with an oscilloscope has more possibilities.
Time and cost savings are another benefit. Fast and accurate diagnosis means less time spent searching for the problem and fewer parts replaced unnecessarily. This, in turn, translates into lower repair costs and greater efficiency for the workshop.
Increased customer confidence is also an invaluable benefit. Customers appreciate fast and accurate diagnosis and a professional approach. With an oscilloscope, mechanics can present customers with accurate measurement results and explain what problems have been identified and how they will be resolved. This builds trust and customer loyalty.
In conclusion, measuring the starter with an oscilloscope is an invaluable tool in the arsenal of the auto mechanic, but also potentially battery dealerships. They make it possible to quickly and conveniently evaluate the starter system regardless of the condition of the battery. If you are not yet using an oscilloscope in your daily work, now is the best time to start. Accurate and fast diagnoses are key to the success of any service center.
DeltaTech Electronics to polski producent i ekspert w branży automotive, który na bazie ponad 25 lat doświadczenia wyznacza trendy w innowacyjnej diagnostyce samochodowej.
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