Engine/Transmission (1994 - 1998) Compression pressure

[TEasley]

When I had the injectors changed out, we did a compression test. Remembered to disconnect the fuel solenoid, forgot to block the throttle open. Pulled all the injectors out and tested that way. Engine was cold and I gave each cylinder 4-5 hits. Lowest pressure was 360#, highest was 370#. I haven't found what it's supposed to be, so I don't know that this is OK. The engine is stock ('97) with 143,000 mi.



It seems good, but I would like to be sure.



Thanks, Tom

 

[JFaughn]

Check this out 17. 5-1 ratio , so that seems like it would be close , under those conditions .

96-98 engine specs

 

[TEasley]

John; Thanks for the link. I bookmarked it. For some reason, they didn't include compression pressure.



Anybody reading this needs to check out this link. I've been on Geno's website but never saw this info. I am not good on computers.



Tom

 

[Bob4x4]

Cummins does not publish compression pressure... ... ... too many variables. They tend to use the dyno and check blowby to gage wear and health.



Bob

 

[Vaughn MacKenzie]

. . . forgot to block the throttle open

Good one TEasley :-laf



Also I've been told a cylinder bleed down test is more definitive than a compression check. I did a compression check on my '96 a couple years ago and they all came out between 500-535psi, but that's not to say it's necessarily better . . . it had 355,000 on the clock back then.



Vaughn

 

[TEasley]

Vaughn; Wish I could take credit for being funny, but that was a holdover from testing gas motors. But I can take credit for dumb. It would have been even funnier if I "had remembered to block the throttle open".

The readings seem good for uniformity, but I am concerned about the values, based on Your readings.



Bob4x4; Thanks for the heads-up. I wondered why I couldn't find compression values.



Anyone else have compression test results to compare?



Thanks, Tom