Compression Test Results

[arayray]

I rented a compression test tool today and ran the test, I did the following:

Disconnected the fuel cutoff button in the trunk
Removed all spark plugs
Tested each cylinder one by one by holding the throttle to the floor and letting it crank 6-7 times.

Here are my results:

4 - 110 8 - 130
3 - 150 7 - 100
2- 100 6 - 120
1 - 170 5 - 150

I ran the test because of a knock/rattle that begins around 3-4k rpm and in conjunction with it burning oil. What do these results say about the current state of the motor?

 

[ashleyroachclip]

You have 3 bad cylinders.
Add a tablespoon of oil to 8-7-2 see if the compression comes up.
Question , was the engine at operating temperature, but cooed enouvh to work on it ?
Or was the engine cold .

 

[arayray]

It was run for about 10 mins prior then it sat for a few minutes. The motor runs and pulls hard other than the knock/rattle and it burning oil.

 

[IA-SteveB]

The fact it runs and pulls hard doesn't mean a lot. Unfortunately, something is going to have to be done about the weak cylinders. Worn rings are likely causing your rattle. Try the tablespoon of oil as mentioned. Remove the plugs on your bad cylinders and put the oil in. Crank it over several times to work the oil past the rings and then install the plugs. Start the car and let it run. If the noise goes away or is a lot less noticeable for a bit, you have your problem narrowed down.

 

[straightpaint]

my avg psi is between 172- 195 between cyl. most of cyl above 185. and thats cranked cold at wot with 64k on motor.

 

[Weather Man]

Time for a refresh.