Low compression

1984 PONTIAC FIERO
74,000 MILES • 4 CYL • AUTOMATIC
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BUDDY HURD
  • MEMBER
  • 1 POST
I bought this car for a toy. The man said he just had the head redone. The car shuts off when put in gear. I checked for vacuum leaks. Found none. Found 90lbs compression in 3 cylinders and 130lbs in the other one. Engine does not smoke or have blow by. What should I do.
Oct 4, 2019 at 10:32 PM
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DANNY L
  • ✓Experienced Mechanic
  • 5,648 POSTS
Hello, I'm Danny.

First thing you can do is perform a a "wet" compression test. Add a small amount of motor oil into the 90 lb cylinders and see if the compression readings come up. If they do that means the piston rings are worn. If you do that and they don't come up I would suspect a faulty head rebuild. Hope this helps and thanks for using 2CarPros.

Danny-
Oct 5, 2019 at 9:08 AM
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