Compression Test Results...

[knkreb]

Scored a new diesel compression tester today.

Did the drivers side (why else?) so far.

Disabled the IP fuel shut off solenoid (which must leak by because it still "wanted" to try to run). So, ended up cracking injector lines as an insurance policy.

I've only ever read of around 400 psi being good numbers. I gave it a few good spins, and all 4 came up with 500 each time....

Did 500 come from a warm engine? Did 500 come from really good starter and engine rpm during test? Did 500 psi come from.... a made in China gauge?

I did one cylinder a little hasty at first and only spun once, and came up to 380 (which I thought would be a normal reading)...

Thoughts?

 

[bk95td]

If I remember correctly it's supposed to turn over a minimum of 4 revolutions . More is better. 400 psi is a minimum for stock pistons/head gaskets.

 

[ak diesel driver]

in our 6.2 service manual min was 300

 

[davo727]

#8 cylinder is the one that likes to have no compression- at least on my 6.5s

 

[buddy]

Probably because you got good cranking RPM it loses less pressure, the important thing is they are all similar. You should just disable the PCM or PMD to prevent fuel from squirting. Unplug ECM fuse or FSOL fuse.

 

[RD400HP]

I bought one of those over there comp tester's and it's a piece of junk, tested a known weak comp motor and the gauge said it had way more than factory, you get what you pay for.

Mark