A tiny amount of air and a different fuel air ratio. There is a tiny amount of air that gets through.


I have done comp tests with the flap closed, and it took 8-10 rotations to get to a high number


Opened the flap and achieved or exceeded that number in only a couple rotations.


One of the first things you do is prop open the flap.


Ive also seen someone use a faulty tool, not have the hose tightened..etc.

 

I wasn't thinking but have done the test with someone turning the key while pushing on the accelerator.

 

Exactly right.

First run the engine (if possible) for a couple of minutes to circulate the oil around.

Take all of the spark plugs out.

Fix the compression test rig into a spark plug hole.

Crank the engine over until it reaches the MAXIMUM reading, it's irrelevent how many times you crank the engine, believe me I have done this hundreds of times on engines.

Don't introduce any oil into any cylinder plug hole, oil is non compressive and so gives a false reading.

Do this on all of the cylinders and then repeat the whole process again just as carefully.

Make a note of each comp test.

Publish the results on here.

If any of the cylinders register a result up to 10% there is some wear, if greater than 10% there is an issue. Good luck.

(don't bother opening the throttle body flap it's irrelevent as it'll purge air from the tickover position or from other cylinders via the inlet manifold)

 

Quick update, Work/life has really hampered my progress but started more tear down yesterday. I noticed that 2 of the 4 bolts that hold down the rocker assembly were loose. The middle two were very loose (back middle was more loose than the from middle). This would be an entirely separate issue from #8 correct?

 

Read any compression test procedure, they will tell you to depress the accelerator.

(Opening the flap)