So guys can I test one cylinder at a time, what I mean is one spark plug at a time off the head? Unplug the main coil pack line? And take out fuel pump fuse? Thanks for any quick replies, ive already got one spark plug off and now I think of this!

 

yeah, just make sure the coilpack is unplugged like you said.

i prefer to take all the plugs out to make it easier to crank over... but you can leave them in and just do one at a time

also make sure you run the same number of revolutions on each test to keep it consistent (i usually do 5).

 

Just remove the fuel pump fuse.
Test each cylinder 3 times, so crank, write it down, reset tester, crank, write it down, reset tester, crank, write it down.
That will give you a good average.

 

from rave:

1. Start and run engine until normal engine operating temperature is achieved (thermostat open).
2. Remove all spark plugs.
3. Disconnect both coil negative (WB) leads
4. Insert compression gauge, crank engine until reading stabilises.
5. Expected readings, throttle fully open, battery fully charged:
8.31:1 = 10.2-10.9 bar, 150-160lbf/in2
9.35:1 = 11.5-12.2 bar, 170-180lbf/in2


Emphasis added.

 

Thank you.
And just so everyone knows, unless you have a '95 or older DI or a RRC you have the 9.35:1 compression ratio.
I do not know the compression ratio of the 4.6.

 

Also have a battery charger on your battery to keep cranking power.

 

You want all plugs removed, or at the very least plugs adjacent to to the one you're testing. This will keep cross cylinder leaks from being masked.
As important as actual readings you want highest to lowest within about 10% of each other. 15% max.

If you have a low reading add a teaspoon of clean oil. If the reading goes up substantially it points to worn rings.

 

Check, thank you all for your replies was able to do test on passenger side of block only got readings from 150-180 on that bank but I did forget to have throttle full open or at least I think my girl forgot to hold open while cranking. will this make my values be higher or lower forgetting this step? Not big differences between cylinders no more than 10-15% so I take it one year later post heads and compression looks good. I Was doing this to just get feel for general engine condition, next day off will do driver side bank. And report and if need be repeat passenger bank if I need to due to not opening throttle during test.

 

Also I used block tester to see if There were any gasses in coolant and she passed no yellow or any discoloration. Yes I was worried about heads due to recent over heats due to tossed belt and what I suspect now a clogged rad that I keep meaning to get looked at.

 

Your numbers are fine.