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Delete this if you want. Got a buddy with a 92 cx 1.5 d15b8. #1 50,#2-100 #3-75,#4-100psi. Obviously needs rebuilt. But could there be something else. Maybe timing belt.

 
Rep Power: 209

low compression can be caused by many different things, i cant tell from here,

- blown head gasket
- damaged valves
- valves not sealing/seating correctly
- burnt valves
- incorrect timing
- extremely worn piston rings (unlikely)
- cam not turning at all (broken timing belt)
- loose spark plugs

 
Rep Power: 518

Cylinder leakdown testing should be the next step.

 
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Less than 150,000 miles #3 plug has alot of burnt oil on it.

 
Rep Power: 208

May be a bad valve or bad rings, do the leak down test.

 
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Thanks

 
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Hello, I'm the friend with the low compression. I am not familiar with the leak down process, how do you do this?

 
Rep Power: 518

Welcome.

Googled:

https://mobiloil.com/en/article/car-...-leakdown-test

http://www.gregsengine.com/cylinder-...n-testing.html

http://www.hotrod.com/how-to/engine/...akdown-tester/

It's basically pressurizing each cylinder with air so you can figure out where the compression loss (cylinder leakage) is.

 
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Thanks for the help, it's much appreciated!

 
Rep Power: 518

I'd sure expect stuck oil rings at the very least.
If the head gets pulled, that would be the ideal time to take care of the rings.