Compression Question

jpjeep26uk

jpjeep26uk

YJ Enthusiast
Joined
Nov 12, 2022
Messages
258
Location
UK
Hi all. Tested the compression on my 4 cylinder 2.5 and these are the results:
Cyl1 - 129
Cyl 2 - 125
Cyl3 - 130
Cyl4- 145

Tried it a few times, they all report the same.
Is this good or bad?
Still trying, after 8 months and some £2000 later, to even get it to start and run properly. Cranks fine, sparks fine, just won't fire and stay fired and the two occasions it did it ran terribly. Had to shut it down due to smoke complaints from neighbours.
Are the compression numbers indicative of something? Thanks all.
 
By the manual, you shouldn't have more than 10 psi (I think may be 15 or something) difference between each cylinder, so technically bad, but I wouldn't think twice about getting numbers like that from an older engine. Those aren't so far off that I would expect poor running due to compression.
 
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DOWNS said:
By the manual, you shouldn't have more than 10 psi (I think may be 15 or something) difference between each cylinder, so technically bad, but I wouldn't think twice about getting numbers like that from an older engine. Those aren't so far off that I would expect poor running due to compression.
Click to expand...

That's great, thanks for confirming.
 
DOWNS said:
By the manual, you shouldn't have more than 10 psi (I think may be 15 or something) difference between each cylinder, so technically bad, but I wouldn't think twice about getting numbers like that from an older engine. Those aren't so far off that I would expect poor running due to compression.
Click to expand...

Do you know what would make the oil presdure gauge show virtually zero when I flick the key to 2nd notch? Before my troubles began, it used to sit juuuuust to the left of middle and then once it fired up it would move to just past middle. Literally put 3.8l of oil in last weekend.
 
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