Needless to say that the communication protocols between the scanner and the computer of different automobile manufacturers are different, so if you are engaged in multi-branded business, you’ll have to buy more than one scan tool or one universal(multi make), but the universality usually means less capable device with way less features. Nowadays some scanners have options even unavailable on original scanners.

Diagnostic tester For Motors.

This is a completely different type of diagnostic tools. Diagnostic Tester – this is precisely the measuring devise. information provided by them taken directly from the engine and allows you to find faults, inaccessible by scanner. Such as voltage and current sensors and actuators, high voltage waveform and pressure waveform in the cylinders, fuel pressure, allows you to test the cylinder balance, measure starter current POPs and more. Let us examine this in more detail.

As everyone knows, the cylinder under the influence of a spark ignites and the combustion of the fuel-air mixture. Monitor and evaluate the process itself (visual or otherwise) is not possible. But evaluate it indirectly very easily. For this purpose, it provided the possibility of withdrawing motor tester wave forms secondary (high) voltage. The shape of these wave forms affects everything: the state of the ignition coil, BB-wire, candle tip, spark, compression, the state of the valve, the composition of the mixture and even computer malfunction. To learn how to extract valuable information from the form of the secondary voltage . In addition, some very interesting examples of wave forms taken at nodes with defective engines and components can be found there.

Another very informative chart in diagnostic tools – the pressure in the cylinder during engine operation. To do this, the tip of the spark plug of the cylinder of interest to us is connected to the spark gap, the spark is turned out, and in its place installed pressure sensor. The resulting measurement chart allows us to conclude:

  1. Correct timing installation phases (not just the belt. For example, broken keys crankshaft and camshaft, crankshaft pulley).
  2. Status of the cylinder-piston and valves.
  3. The presence of an air leak in the intake tract.
  4. The high back pressure exhaust system (collapsed catalyst inside or the muffler destruction).
  5. Real angle ignition timing.

Indeed an impressive list. Only one – correct installation phase makes it worthy. Manually, this operation is long and difficult, but with the help of motor testers can be solved effortlessly in five minutes.

Another great reason of having diagnostic tool is to determine whether the place has no breakage or inter turn fault injectors. It makes possible to measure the current amperage  on starter to conclude the battery and the starter status . Generator voltage waveform allows to conclude it’s “health”.

Diagnostic tool enables you to test the sensors. Example. Mass Air Flow Sensor (DFID). Remove the waveform signal from the sensor when it is turned on. The shape of the transition process, you can immediately, without starting the engine, make a conclusion about his health. How to do it, it is told in one of the articles.

Well, was that impressive? If you are convinced of the need to purchase such device, it’s only left to chose a particular model. Unfortunately, due to the above mentioned diagnostic tool is the most expensive amount diagnostic tools. Selection of companies and models is large enough. In terms of price / quality .

Gas analyzers.

Here I will say only one – the modern diagnostic depo should only be equipped with four-component analyzer. Two-component devices, as well as carbs is history. And yet – the analyzer is not for the “CO2 adjustment”, but as a source of diagnostic information. How to use this information.

A brief summary.

All three types of devices described are completely different operating principle, providing  us with different information and in any case do not replace each other. Yes, somewhere the data derived from them is the same and in some cases they are very unique. In principle, it is possible to work without any of these devices (there are “specialists”, which generally need only a screwdriver). It’s not what this article about. It’s about the fact that a competent search of the defects based on the analysis of information, on precise measurements, where as we know the science begins.

The rest of the equipment is essentially auxiliary in nature, although its presence is more than desirable.

Set for cleaning nozzles. Ultrasound with spilling stand (very useful thing), or liquid.

Stands for checking the spark plugs, ignition modules.

Quality multimeter, preferably non-Chinese production.

A good set of tools. Branded desirable.

All kinds of probes.

How to use Diagnostic Tools For BMW – Autohex II

BMW diagnostic tools work consists of three phases: collecting information, its processing, decision-making. Actually the process can be described as follows.

  1. Customer Survey for the nature of the problem. When, how, under what circumstances the defect appeared. In fact “interrogation” of the client often greatly facilitates the further search.
  2. Visual inspection of the engine compartment. Carefully look for any obvious damage wiring, hoses, high-voltage wires. Are there any traces of tampering, mostly from car alarm installers. Typical cases: the wiring going to the timing sensor after the engine bulkhead is lying on the exhaust manifold, or wires from the speed sensor are cut off when the clutch is replaced. In general, the previous interventions should be given serious consideration. It is useful to make sure that all crankcase ventilation hoses, canister, etc. are on their regular places, ECM fuse is not blown, and the tank has a fuel. It is advisable to check the condition of the air filter. it is often torn, and this leads to the air mass sensor failure.

Only after all this you are ready to work with devices.

  1. Start with scanner. Check the error codes, clear the list and repeat.
  2. Visually control the plugs. The quantity of soot, its color, the gap, the state of the electrodes, the presence / absence of the breakdown of the insulator. Unfortunately, for that the only help is from your own experience and intuition.
  3. Check the static readings of sensors and actuators using a scanner. You can move the Idle sensor, turn the fan and the fuel pump on and off, balance injectors etc.
  4. Perform BMW diagnostics using BMW Diagnostic tool like Autohex II on fuel supply system pressure.

Unless problems with the pump, pressure regulator, sensors, MI, candles and wires in a static, start the engine.

  1. With the engine running redo the scanner check , the same parameters. It also requires experience.
  2. Print a gas analyzer readings.
  3. You can remove diagnostic tool high voltage waveform, if needed.
  4. If there is a suspicion of incorrect installation timing phases BMW Diagnostic Tool execute test pressure in the cylinder.
  5. And now the most interesting. Carefully look at the results, analyze them and draw conclusions.

Sometimes, in cases of doubt, it makes sense to replace the defective item and take readings again or perform a test drive.

Personally I use Autohex II as my main BMW diagnostic tool , However there are many good diagnostic software in the market, you better to pickup the one which fits your requirements and budget.