2010 VW Golf 1.4L TSI Compression Leak

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Re: 2010 VW Golf 1.4L TSI Compression Leak

Post by victor2k » Wed Jul 19, 2017 8:39 pm

Technician wrote:Am I reading the scope data correctly!!

Compression pressure between 77 and 88 psi !!

Manufacturer minimum spec I see is 150 psi
Yes but look at the vacuum-the throttle valve is closed so the compression will be lower than the specified.
Also you must add the parasitic volume of hoses ...thanks to STC you can correct the value.

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Re: 2010 VW Golf 1.4L TSI Compression Leak

Post by STC » Wed Jul 19, 2017 8:45 pm

and let me tell you why:
a lower compression (without a leaking at intake, exhaust or at the rings) will be accompanied by a lower escaped pressure in intake,exhaust or carter
Yes that is true! and off topic !!

None of this will confirm or deny an Injector seal leak.

And we still have the fact that a Cylinder Leakage Test using shop compressed Air has confirmed that there is No Leak.?
Cylinder leak may not be dynamic or in real time but it has for decades proved to be a reliable test.

Low compression in a cylinder does not have to be a leak ? In this car, based on evidence provided, I am not sure it is a leak.

We will see.
Last edited by STC on Wed Jul 19, 2017 8:57 pm, edited 1 time in total.

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Re: 2010 VW Golf 1.4L TSI Compression Leak

Post by Technician » Wed Jul 19, 2017 8:53 pm

victor2k wrote:
Technician wrote:Am I reading the scope data correctly!!

Compression pressure between 77 and 88 psi !!

Manufacturer minimum spec I see is 150 psi
Yes but look at the vacuum-the throttle valve is closed so the compression will be lower than the specified.
Also you must add the parasitic volume of hoses ...thanks to STC you can correct the value.
Yes I saw the vacuum point duly noted thanks. Where did STC correct the values for adding parasitic volume?

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Re: 2010 VW Golf 1.4L TSI Compression Leak

Post by victor2k » Wed Jul 19, 2017 9:00 pm

STC wrote:
and let me tell you why:
a lower compression (without a leaking at intake, exhaust or at the rings) will be accompanied by a lower escaped pressure in intake,exhaust or carter
Yes that is true! and off topic !!

None of this will confirm or deny an Injector seal leak.
:lol: can't be true and false at the same time!
Maybe the leak is too small to be measured...also I think we go in a wrong direction.The timing wasn't confirmed ,also the valve clearance wasn't checked!
Regards
Last edited by victor2k on Wed Jul 19, 2017 9:08 pm, edited 1 time in total.

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Re: 2010 VW Golf 1.4L TSI Compression Leak

Post by STC » Wed Jul 19, 2017 9:01 pm

Where did STC correct the values for adding parasitic volume?
Here

post64411.html?hilit=compression variation#p64411

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Re: 2010 VW Golf 1.4L TSI Compression Leak

Post by STC » Wed Jul 19, 2017 9:06 pm

Victor
can't be true and false at the same time!
What you wrote is true. very true. but it can be false if there is no leak.
Maybe the leak is too small to be measured...
If there is a leak ??? :D
The misfire is throwing a fault code - If the ECU can see it - Pico WILL find it !!! :D

It is possible to have low compression in a single cylinder that has no leaks

I keep beating this drum because I have seen and solved this on a 1.4 VAG FSI some 4 years ago.

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Re: 2010 VW Golf 1.4L TSI Compression Leak

Post by victor2k » Wed Jul 19, 2017 9:17 pm

STC wrote:Victor
can't be true and false at the same time!
What you wrote is true. very true. but it can be false if there is no leak.
Maybe the leak is too small to be measured...
If there is a leak ??? :D
The misfire is throwing a fault code - If the ECU can see it - Pico WILL find it !!! :D
Sorry but the poetry overtakes me...
And sometime Pico can't see without a proper sensor what is wrong in engine!Also isn't enough 12 bits ADCs to see some small signals...and sometimes with all the infos we can't see the truth. :?
I think we have a similar case to this:
topic17241.html-our cyl3 can have excesive exhaust valve clearance(lower compression and a peak of pressure at aprox 360^).
Last edited by victor2k on Wed Jul 19, 2017 9:28 pm, edited 1 time in total.

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Re: 2010 VW Golf 1.4L TSI Compression Leak

Post by STC » Wed Jul 19, 2017 9:28 pm

Victor

Once again!

It is possible to have low compression in a single cylinder that has no leaks

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Re: 2010 VW Golf 1.4L TSI Compression Leak

Post by victor2k » Wed Jul 19, 2017 9:33 pm

STC wrote:Victor

Once again!

It is possible to have low compression in a single cylinder that has no leaks
But where I said this?with a bented conrod,a lower opening of valves ,a missing injection or ignition or a bad seal of injector you can have a low compression.Here I think we have the second case(based on image from post 9).

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Re: 2010 VW Golf 1.4L TSI Compression Leak

Post by STC » Wed Jul 19, 2017 9:40 pm

A bent con rod could affect intake vacuum on a petrol engine with an operational throttle flap - yes !

This is a GDi - they are different

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