89 F-150 engine woes
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New User
Joined: Dec 2004
Posts: 1
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From: Fairfax Va
89 F-150 engine woes
My 89 f-150 4.9 litre is having compression problems and is constantly missfiring.
The missfiring is not caused by spark plugs or anything like that and the problem seems to be internal. Otherwise the truck is in great condition at 175000 miles and has recieved all proper maintenance. Please help if you have any ideas as to the problem
The missfiring is not caused by spark plugs or anything like that and the problem seems to be internal. Otherwise the truck is in great condition at 175000 miles and has recieved all proper maintenance. Please help if you have any ideas as to the problem
Elder User
Joined: Sep 2004
Posts: 941
Likes: 4
Compression problems? You mean low compression in one cylinder?
If you actually ran a compression test, post the results. Run it wet and dry and figure out whether the leakage is valves or rings.
If one cylinder was below 40PSI or so, it will not fire no matter how good the iginition system.
If you actually ran a compression test, post the results. Run it wet and dry and figure out whether the leakage is valves or rings.
If one cylinder was below 40PSI or so, it will not fire no matter how good the iginition system.
