VW Golf4 BCB not start

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Fat Freddy
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Re: VW Golf4 BCB not start

Post by Fat Freddy »

I found myself in the past counting for crank pulses after TDC mark, to be more sure about timing events and angle, not trusting the rulers.
No need to count. Use edge count if you require that sort of accuracy. Way quicker. :)
Volkswagen_Golf_2002_Petrol_20161211-0001.psdata
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Which in fact makes the exhaust cam appear even more advanced by a further 4* approx.

HTH
FF

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Fat Freddy
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Re: VW Golf4 BCB not start

Post by Fat Freddy »

victor2k wrote: My madness started from a similar event to the following images(captures was made with the same setup on Ford Puma 2002 /petrol/1.6l):30* diference on a non-vvt engine between first and second measurement(vvt or non-vvt does not matter at cranking and idle anyway)! :evil:
Thank you.

I don't think I'm totally understanding what you are measuring. I could be wrong but it looks like you are comparing exhaust ramps between cranking and idling. It's never going to be comparable. As a cylinder under vacuum on the exhaust stroke (idle, 1/2 a bar) is never going equalize to exhaust at the same rate of rotational degrees as one cranking - poofteenth of a bar vacuum to equalize to exhaust pressure.
Two different pressures to equalize at two different crank degrees per second. It's not really comparable.

You would get better results measuring the start of the event.

Hope that makes sense.
FF

victor2k
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Re: VW Golf4 BCB not start

Post by victor2k »

Volkswagen_Golf_2002_Petrol_20161211-0001.psdata
Which in fact makes the exhaust cam appear even more advanced by a further 4* approx.

HTH
FF
Hello,
Thank you for solution.
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Fat Freddy wrote:
I found myself in the past counting for crank pulses after TDC mark, to be more sure about timing events and angle, not trusting the rulers.
No need to count. Use edge count if you require that sort of accuracy. Way quicker. :)
Volkswagen_Golf_2002_Petrol_20161211-0001.psdata
Which in fact makes the exhaust cam appear even more advanced by a further 4* approx.

HTH
FF
Hello,
Thank you for solution.