Compression test

[Terranoman]

Afternoon all,

Hopefully someone can help me with this.

I have just tried to do a compression test on the T2 and cannot get a pressure reading on any of the readings.

When turning over the needle goes upto 200/300 psi but does not hold and drops back down within a second to zero then back up etc....

Any ideas why?

Cheers

Mark

 

[micktheshed]

Are you sure the valve on your gauge will hold pressure? Sounds silly but I've had them fail.
If the gauge is OK then I assume you've tried after injecting a teaspoon of thin oil into the cylinders so as to temporarily eliminate leakage past the rings?
Yes?
Then it points to all the valves not sealing which is bad news but quite rare.

 

[rustic]

Is there also a leak off valve or button on the compression tester to zero the meter, if so this could be leaking too.:nenau

I have never used one but it should measure the peak pressure and hold it, until you decide to reset it. :augie

 

[Lazy-Ferret]

Just to ask a silly question, you are using a Diesel Compression tester, and not a petrol one?

Petrol ones generally go up to about 300PSI, but Diesel ones go a lot higher to about 600PSI or more.

 

[Terranoman]

Thanks for the replies.

Def Derv tester.
No leaks.

Will try the oil trick:thumbs

Dont know if faulty. Its only been used 2-3 times

Mark

 

[Lazy-Ferret]

Just as a matter of interest, are you doing it through the Injector holes, or the glow plugs? If the Glow plugs, have you disconnected the fuel pipes from the injectors?

When Rick was working on my car last week, we spun it over with the glow plugs removed, but the injectors still connected up, and she fired over, so there is a lot of compression held back in the piston buy the small orifice between the head and cylinder.

 

[Terranoman]

I was testing through the glowplug. Fuel lines are still connected.

I did disconnect the fuel fuel pump so the engine would not start.

 

[macabethiel]

Compression Test

Afternoon all,

Hopefully someone can help me with this.

I have just tried to do a compression test on the T2 and cannot get a pressure reading on any of the readings.

When turning over the needle goes upto 200/300 psi but does not hold and drops back down within a second to zero then back up etc....

Any ideas why?

Cheers

Mark

Daft question buy why are you doing a compression test ?

My late Dad always said if its running OK do not do a test and then have the worry of a low reading on one of the cylinders.

A bit of the "if it ain't broke don't fix it" syndrome.

 

[Terranoman]

I had an overrun issue where I was a nob and put to much oil in. The engine now has a bit of a clatter when running so was trying to find out if valve or piston problem.