Hello,
I am another new guy to this forum. I am curious if anybody is considering ways to diagnose in a reliable way if there are deposits on Intake valves of GDI engines or even PFI engines? Is there a difference in vacuum signal or maybe as Tom Roberts suggested compression signal when deposits are on the intake valves?
Thank you
Mike

drfuelinstein wrote on Oct 16^th, 2015 at 12:43pm:

Hello, I am another new guy to this forum. I am curious if anybody is considering ways to diagnose in a reliable way if there are deposits on Intake valves of GDI engines or even PFI engines? Is there a difference in vacuum signal or maybe as Tom Roberts suggested compression signal when deposits are on the intake valves? Thank you Mike

Welcome to the Nerdz Forums,


You may want to post in the Pico Scope help section, more eyes will see it there, as far as your question, I have not played around with a WPS or FLS on a known engine with GDI carbon issues, I do know that you can look at calculated load and fuel delivery to determine if there is a flow restriction.

In my experience, you will have a hard time determining deposits on intake valves unless it is only one cylinder affected. Usually all cylinders will bung up making it hard to pin point that they're bad. What you need to look at is overall air intake volume. The problem is that you need to know what good is first.

I once hooked up a scope to a stereo speaker and watched the waveforms of the voltage played as notes.
Sound has a frequency; and the frequency of the intake manifold sound when clean must differ from that when it walls have a different shape, chemical constitution and size, as when coked and dirty.

So I wonder if a microphone in the intake might be useful?