Looking for opinions on compression numbers


Crater05

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Nov 14, 2021
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Indiana
Hello, I am just looking for some advice. So I noticed my '93 2.5l was idling a little funny, so I did a compression test on all 4 cylinders. All ranged between 60-75. I have read that at least 100-120 is optimal. If this is a problem what could it be?
 

Gilaguy23

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Apr 12, 2021
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Q town New Mexico
Yes, thats low by a good stretch. You should by in the 120/150 range and each cyl within 10 to 15% of each other. Are you sure you had a good seal on the tester and held the throttle open all the way to allow for air to enter the cyls.
 
OP
C

Crater05

New Member
Joined
Nov 14, 2021
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2
Location
Indiana
Yes, thats low by a good stretch. You should by in the 120/150 range and each cyl within 10 to 15% of each other. Are you sure you had a good seal on the tester and held the throttle open all the way to allow for air to enter the cyls.
Okay, I'll try one more time holding it full throttle to make sure before I try anything else.
 

redbullet

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May 11, 2021
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San Jose, CA
If after your retest you do have that low of compression next step would be to do a leak down test to determine what is causing the problem. See here if you want to diy:

 

T-Rex Jeepster

The Unoffendable
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Sep 13, 2021
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Middle Tennessee
Warm and wet......If she's warm and still weak, Spray some WD-40 or PO into the cylinders and check again....No improvement?
If it's not smoking, That eliminates the rings and you probably have valve/head issues............
 

Wmaltby

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Jun 4, 2021
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Zionsville
Chiltons say 135-155 psi
Put just a small amount of oil in the cylinder, through the spark plug hole and repeat test to see if it’s rings or valves. If compression does not improve with lil, then most likely valves.
My long block is at machine shop now going 30over.
Machine shop speaks highly of this little engine. ……