Intake Valve Carbon Build Up

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ashtray1987
OneWave
OneWave
Posts: 48
Joined: Tue Jul 25, 2017 11:52 am

Intake Valve Carbon Build Up

Post by ashtray1987 »

Hi Guys,

Do any of you have any experience with proving intake valve carbon build up, perhaps using the WPS500X?

For some particular engines, getting access to the intake valves with an endoscope is nigh on impossible, therefore I am hoping there is a better method using the Picoscope.

This is only relevant for direct injection gasoline engines, where the carbon build up is enough to cause misfiring.

I know we can see it in the secondary ignition pattern by turbulence in the burn time, but this doesn't necessarily conclude the carbon build up as the cause. As I have seen the same symptom with broken variable intake manifolds and swirl flaps.

Has anyone got any recordings using the WPS500X during a compression test, both before and after the cleaning procedure?

My guess is that we will see a lot of turbulence whilst the intake valve is opening?

Appreciate if any of you have any suggestions or experience on this topic.

Thank you.
Ashley

speck
TwoWaves
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Joined: Sun Mar 25, 2012 5:20 am

Re: Intake Valve Carbon Build Up

Post by speck »

Are you talking about one cyl ? If you got bad restriction you should see that in a secondary
capture.
Hope that helps

ashtray1987
OneWave
OneWave
Posts: 48
Joined: Tue Jul 25, 2017 11:52 am

Re: Intake Valve Carbon Build Up

Post by ashtray1987 »

Hi Speck,

No not 1 cylinder, normally the carbon build up is quite even across all cylinders.

The issue is, that the secondary ignition pattern will show turbulence, but that will not conclusively determine whether there is intake valve issues. There could still be issues with the variable intake or swirl flap/tumble flaps, causing turbulent airflow into the cylinder. With direct injection, these unstable air causes a lot of issues with smooth running/misfires.

This is why I was hoping we could see something with the WPS500x during a compression test.

Thank you.

speck
TwoWaves
TwoWaves
Posts: 63
Joined: Sun Mar 25, 2012 5:20 am

Re: Intake Valve Carbon Build Up

Post by speck »

I know what you mean, need to have tumble flaps wide open , variable intake in org. position.
Bad restriction will show up us low compression. Have expierenced it on FSI Golf engines.

ashtray1987
OneWave
OneWave
Posts: 48
Joined: Tue Jul 25, 2017 11:52 am

Re: Intake Valve Carbon Build Up

Post by ashtray1987 »

Thank you for the information.

Do you have any before and after recordings?
Cheers
Ash

speck
TwoWaves
TwoWaves
Posts: 63
Joined: Sun Mar 25, 2012 5:20 am

Re: Intake Valve Carbon Build Up

Post by speck »

Sorry don't keep any secondary because there is no reason for that, none looks the same.Volumetric efficiency
is what you are looking for. Place plug extension leads onto your coils,tumble flaps and vvt disabled. Look for low compression (KV spike)
Good luck

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