Margate330

Hi folks,
Today I did a compression test on my front bank and I wanted to share more fun stuff with the community.
I also replaced the spark plugs again while I was at it just for fun. lol
Plugs: Denso SK20R11 Iridium, Gap(0.043"), Torque(156 inch-lbs or 13ft-lbs)
Here is how I did it.

Step#1:
I drove to the store to get spark plugs and got the motor warm.
Then when I got home I let the motor cool for 1/2 hour so the motor wasn't cold but just above warm.
*Note- I never remove plugs from a hot engine with aluminum heads cuz I watched a coworker mechanic strip the spark plug threads on a Subaru with aluminum heads one time doing that.

Next I pulled all three coil packs and plugs on front bank

Step #2:
Next thing I did was loosen the master cylinder brake fluid reservoir and move it a little so I can access the hidden relay box under it (this is where my EFI Fuse is located).
*Note- there is a small wire harness in the way. Using a razor knife I cut the electrical tape and moved the harness out of the way of the 10mm bolt holding down the brake reservoir.
Here is where my EFI relay is located(see pic below)

There were 3 relays in a row on left side. My EFI relay was the bottom left relay(as seen in pic above and as seen on inside of relay box cover).
*Note- This relay was in very snug. It took some wiggling to get it out.

Step #3
I installed my Harbor Freight compression tester into the spark plug hole until it was hand tight and turned my key and turned the motor over a few times.




Next I tested the remaining two cylinders.

My compression test results for bank 2 were:
Cylinder #2: 182 psi
Cylinder #4: 185 psi
Cylinder #6: 185 psi

PS- my compression tester is a cheap one so I'm not expecting perfect accuracy but it gives me a ballpark number.

Car: 2004 RX330 FWD
Mileage: 148K

If someone has info on a better way to disable ignition and fuel to test for compression plz let me know but this worked well for me.
Anyone else done a compression test please share.

Update: 04-09-2020

Here is a relative compression waveform at 152K miles.
For a quick test this works good.