![]() ![]() It is vitally important that all air is bled from the spill hoses and the WPS500X pressure transducer before you analyze the waveform for irregularities. Analyse back-leakage pulsations and pressure under conditions equal to the ones reported by the customer. Note: Back-leakage pressure and pulsations will change in relation to engine speed and load. Typical values with an engine at correct operating temperature, idling and no load applied. ![]() Refer to vehicle technical data for specific test conditions and results. While the vehicle tested above did not exhibit any running issues, there is a clear difference in contribution (at idle speed) to back-leakage pulsations between injectors 2 and 3. This lets you analyze the waveform for irregularities attributed to injector malfunction. Zoom level 3 now amplifies the dynamic fluctuations within the back-leakage pressure signal, by magnifying the pulsations 1000 times. When selecting ZOOM LEVEL 3 of your WPS500X, the back-leakage pressure value obtained in Example waveform 1 (25 mbar) is centered around the 0 mbar marker (black dotted line) and no longer represents the pressure value. We advise that you recharge your WPS500X after each use to ensure it is ready for future measurements. While the engine is idling, select Zoom 3 from the front of the WPS500X to magnify the spill pulsations in preparation for closer analysis.Let the engine return to idle while you record the spill pressure value and the pulsation formations.This will purge the air from the injector back-leakage circuit and the WPS500X. When the engine is at the correct operating temperature, you can carry out numerous momentary Wide Open Throttle (WOT) snap tests.Crank and start the engine, and allow idle speed to stabilize.Run the PicoScope software by pressing either the space bar on your keyboard or the Go button in PicoScope.Connect the WPS500X pressure transducer to Channel B of the scope with the BNC to BNC test lead.Press the range button on the WPS500X and select Range 3 (-5 to +5 Psi).(The bleed valve should remain open throughout the test.) Open the bleed valve on the WPS500X and fix in the open position with a heavy duty cable tie.Connect the bleed hose to the WPS500X and feed the hose into a sealed container.Connect the Vacuum hose (TA085) to the quick couple connector on the WPS500X.Connect a donor spill type hose to the spill stub of the relevant injector located in step 3, and link the opposite end of this spill hose to the Vacuum hose (TA085) with the Vacuum adapter (TA129).Make sure that the pipe is sealed to prevent contamination. This is often located at injector number 1 or number 4 on a 4-cylinder engine. Remove the spill pipe from the injector that returns leak-off to the fuel tank.(The LEDs will scroll from range 1 to 3 and revert to 1.) Switch on the WPS500X and wait for the self-test to complete.This will enable identification of the pulsations in the back-leakage waveform, indicating offending injectors. Connect the 20/60 A current clamp (TA189) to Channel A on PicoScope and link the clamp around the signal wire of the number 1 injector. ![]()
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