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There are times when running problems occur that can not easily be identified using a scanner
In such cases a Motor Tester can be used
Let's see how to use the USB Autoscope and the CSS Script by Andrey Shulgin
Connecting the device is easy
It connects to the computer's USB port by way of a USB 2.0 A/B interface cable
Connect the ignition system adapter to the USB Autoscope using the appropriate cable
Connect the ignition system adapter power supply wiring to the vehicle battery
using red for positive and black for negative
The black synchronization pickup is used for identifying when spark occurs for cylinder number 1
Connect the synchronization pickup to the ignition system adapter and then clip it to the ignition cable for cylinder number 1
To obtain the crankshaft position sensor signal it is necessary to use a test lead
Connect the test lead to input number 5 on the USB Autoscope
Place the black clip to ground
Clip the other lead to the signal wire for the sensor. You can use a needle probe to make it easier, if necessary
Start the USB Oscilloscope program and select the "CSS" mode
Start the engine and leaving it idling
Select record
and after a few seconds slowly raise the engine speed to 3'000 RPM
Let off on the throttle and wait until the engine returns to idle.Then abruptly open the throttle
and when the engine has achieved 3'000 RPM, turn off the ignition
but leave the throttle open
Wait until the engine has completely stopped turning and stop the recording
Next you will need to analyze the recorded waveform
To do this click "Run Script" in the USB Oscilloscope window
The script will output multiple tabs
The "Report" tab shows the formula for the crankshaft reluctor (60-2), and which tooth coincides with TDC for cylinder number 1
The "Efficiency" tab shows the effectiveness of each cylinder at various points during the recorded data
The "Ignition Timing" tab shows the relative ignition timing depending on speed and load
The "Toothed Disc" tab displays the parameters of the crankshaft position sensor and reluctor
Let's go back to the efficiency tab
You can see that the compression for all cylinders is the same
The ignition system is working properly
There is no problem with the fuel supply
We can look at each cylinder individually
by left clicking on the desired cylinder
We can conclude that all of the cylinders are working equally at all points during the recorded data
Let's carry out the same test on another vehicle
The setup is the same
Start the engine
and let it stabilize
Slowly raise the engine speed to 3'000 RPM
let off on the throttle and wait until the engine returns to idle
Abruptly open the throttle, all the way, and when the engine has achieved 3'000 RPM, turn off the ignition but leave the throttle completely open
Stop the recording
To analyze the recorded data click "Run Script"
According to the "Report" tab, the reluctor formula is 36-1 and cylinder number 1, top dead center, is 9 teeth before the missing tooth
Notice in the "Efficiency" tab there are deviations in the red and yellow graphs showing a problem with cylinders number 1 and 3
The ignition timing appears normal
The reluctor and crankshaft sensor appear normal, as well
Let's look closer at the "Efficiency" tab
From the graphed efficiency of the 1st cylinder we can see the misfire occurring during snap throttle
This indicates a problem with spark in that cylinder
The end of the graph for the 3rd cylinder indicates a problem with compression
which has led to a decrease in efficiency
The graphs for the 4th and 2nd cylinders show no faults
What was wrong?
The misfire in the 1st cylinder
was due to a cracked spark plug and a defective ignition cable
The reduction in compression for the 3rd cylinder was due to a burned valve
http://injectorservice.com.ua/