Compression Test - Am I doing this right?

[Numero9]

08 standard GTI

VCDS states I have a various misfires but repeating on cylinder 3 so I decided to investigate the cause before I start to strip the engine to do the cam chain.

I swapped coil pack 3 to 4, issue remained on cylinder 3
I swapped the plug 3 to 4, issue remained on cylinder 3

Next step was to do the compression test. I borrowed the tested from a friend and screwed into cylinder 1 (M14 thread adaptor), removed 15A fuse F27 from passenger side box which I believe to be the fuel pump? I cranked it 5 times and each time it made an awful squeak/screach like the air was escaping out and read 0bar. Wasn't sure what was going on so moved onto the rest of the cylinders and they all did the same sound and all ready very poorly. I am unsure if its a dodgy tester, user error or if the engine is truly goosed.

Cylinder 1 - 0 bar
Cylinder 2 - 2 bar
Cylinder 3 - 4 bar
Cylinder 4 - 4 bar

Each time I cranked the tested would pulse up but would immediately loose all the pressure but I cannot say how much as it was quite dark and visibility of the gauge wasn't the best, anyway any help or tips would be most welcome?

[mjmallia]

Has it had the intake carbon cleaned as thus really clogs up the intake valves and causes sealing and misfire issues. Happened to me and common to all direct injection engines.

[Numero9]

Has it had the intake carbon cleaned as thus really clogs up the intake valves and causes sealing and misfire issues. Happened to me and common to all direct injection engines.

Not since I've had it and nothing in the paperwork to say it has been done. Doesn't really mean I would get such a weird result for the compression test though?

[mjmallia]

If the valves are carboned up and not sealing properly then compression would be an issue

[Octoparrot]

08 standard GTI

VCDS states I have a various misfires but repeating on cylinder 3 so I decided to investigate the cause before I start to strip the engine to do the cam chain.

I swapped coil pack 3 to 4, issue remained on cylinder 3
I swapped the plug 3 to 4, issue remained on cylinder 3

Next step was to do the compression test. I borrowed the tested from a friend and screwed into cylinder 1 (M14 thread adaptor), removed 15A fuse F27 from passenger side box which I believe to be the fuel pump? I cranked it 5 times and each time it made an awful squeak/screach like the air was escaping out and read 0bar. Wasn't sure what was going on so moved onto the rest of the cylinders and they all did the same sound and all ready very poorly. I am unsure if its a dodgy tester, user error or if the engine is truly goosed.

Cylinder 1 - 0 bar
Cylinder 2 - 2 bar
Cylinder 3 - 4 bar
Cylinder 4 - 4 bar

Each time I cranked the tested would pulse up but would immediately loose all the pressure but I cannot say how much as it was quite dark and visibility of the gauge wasn't the best, anyway any help or tips would be most welcome?

I think if the compressions were really that low then the car would barely run.

[Numero9]

So confirm it was a bad tester. I got a different one and it ran perfectly, 180PSI in each cylinder after 5 cranks. All good on the head and likely just a bad injector, new repair kit, inlet manifold gasket and injector on order and will fix along with the cam chain