Diagnostics using Pressure Transducers

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Re: Diagnostics using Pressure Transducers

Postby hexibot43 » Mon Oct 27, 2014 4:03 am

I've been following this conversation the best I can.

I have a question regarding the Intake valve being masked. We are measuring the pulses at the exhaust, and not from within the cylinder like the WPS is capable. We are looking at the events from outside the cylinder through the exhaust valves. Couldn't this explain the questions regarding the intake events being masked? Our window into the cylinder is only open when the exhaust valve is open.

What do you all think?
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Re: Diagnostics using Pressure Transducers

Postby Valhalla » Mon Oct 27, 2014 11:44 pm

Generally true, I would agree. To throw another spanner in the works, we would also have to consider visibility of the cylinder via the intake manifold when the EGR valve was open as well. Less a problem with gasoline until higher speeds/loads, but very likely at idle speed/load with a diesel.
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Re: Diagnostics using Pressure Transducers

Postby Fat Freddy » Wed Oct 29, 2014 10:37 am

I have a question regarding the Intake valve being masked. We are measuring the pulses at the exhaust, and not from within the cylinder like the WPS is capable. We are looking at the events from outside the cylinder through the exhaust valves. Couldn't this explain the questions regarding the intake events being masked? Our window into the cylinder is only open when the exhaust valve is open.


That's pretty much what I am questioning. As the FL is displaying speed of change more than actual values. How can you tie it to the inlet valve opening?
I have an image that backs this but what I don't get is how Steve has got two FL captures from (what appears) to be the same vehicle under the same conditions. :?
The image then makes it look like square pegs and round holes. :?

Regarding diesels I expect completely different captures. Would be good to see.

Cheers
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Re: Diagnostics using Pressure Transducers

Postby sigoaprendiendo » Sat Jan 17, 2015 10:13 pm

Hi there, FF and Steve:

Here you are another related files with the same subject, so you have the chance to play a little, I am sure that will be easy for you as both of you are experts in this issues. I am just learning every day from this forum especially from both of you. Thank you very for sharing with our community your every day insights with us.

This car has a rough idle and when we try to snap throttle it doesn't kick in the way is supposed to be.

This guy is 1994 Ford Mondeo 1.8L Petrol.

The second belongs to a '97 Ford Mondeo 1.8L Petrol as well but runs better

Kind regards:

Dario
Attachments
Cold Crank Exhaust Tail Pipe Test Ford_Mondeo_1997_Petrol.psdata
(2.07 MiB) Downloaded 138 times
Cold Crank Exhaust Ford_Mondeo_1994_Petrol.psdata
(7.03 MiB) Downloaded 111 times
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