I saw this at AES wave which might give you some insight to the engine issues in a fairly non intrusive manner.
pressure transducer
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can any one give me an idea of the settings for the vantage pro when you load the preset screen for the transducer it sets the time up for 50ms. When I zoom in to the max it will not show me enough of the wave form to dignose what is going on. Also do you guys use a check valve in the pressure hose like you do for old school compression test I would guess not due to you wanting to be able to read the pulses of the cylinder. Channel 1 is channel with transducerAttached FilesComment
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can any one give me an idea of the settings for the vantage pro when you load the preset screen for the transducer it sets the time up for 50ms. When I zoom in to the max it will not show me enough of the wave form to dignose what is going on. Also do you guys use a check valve in the pressure hose like you do for old school compression test I would guess not due to you wanting to be able to read the pulses of the cylinder. Channel 1 is channel with transducer
You might try using the 200 ms sweep to start then adjust as needed, but 50 will work as long as you don't zoom too far out.
Yes, you want to test with the valve out of the pressure hose.Comment
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Thanks I was doing static compression test car will not run I wanted to check valve timing with out taking timing cover or valve cover off. It is a 01 sentra with 1.8L . I am going to try to display Ignition coil signal on channel 2 and see if valve timing is off kind of new to this type of diagnostic this my 1st attempt at using a compression wave formComment
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Can some of the experts look at this and tell me what you see this is a vvt engine. I dont see a dip in form when exhaust valve opens maybe it has restricted exhaust?Attached FilesComment
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(Suck, Squeeze, Bang ,Blow )The tops of the humps is usually TDC on compression, the descending right side of the humps is the piston going down on (what would be) the power stroke, but it appears to be going into a negative pressure condition before it goes to zero psi. Not sure should see that before the exhaust valves opening though. Try checking the engine cranking vacuum with the transducer, and if the valve timing is correct and valves are sealing correctly , I don't think you should be seeing any significant positive pressure spikes.
If you suspect an exhaust restriction , take out the upstream O2 sensor and rerun the tests.Comment
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Thanks for the replies I have shot with with ignition trace I know the voltage on the ignition trace is wrong but it shows trace along with compressionAttached FilesComment
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