Odd Compression Test Results
Performed a compression test today since I'm starting to compile a list of parts for a turbo project. Car is a 2005 with 150,200 miles. I've only had it for 2 years and 5,000 - 6,000 miles.
Engine was warm, all 4 spark plugs removed, fuel pump fuse removed, throttle held open while cranking. Results: Cylinder 1 - 190 Cylinder 2 - 218 Cylinder 3 - 220 Cylinder 4 - 265 Obviously cylinder 1 is low and 4 is high. Cylinders 2 and 3 seem to be normal. Why would cylinder 4 read so high? Cylinder 1 being low makes me think maybe exhaust valves? But from what I've read here on the forums, 06-09 are usually the ones with tight exhaust valves. I'll rent a leak down tester and see where its leaking from. Any ideas on these numbers? |
Any chance your battery was running low by the time you tested #1? (Was #1 tested last?)
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#1 was tested first, and then tested a second time at the end. Same results. Battery was fine.
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Carbon build up ?
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Try a wet test and see if there's a difference. Check and adjust all valves. Re-test.
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Valve adjustment findings
Went ahead and performed a valve adjustment last night. Check out the before and after, some of these are really odd. Some exhaust valves were tighter than my smallest feeler gauge, which is .005". This poor car has probably never had a valve adjustment. Most of the intake valves were in spec. I set all intake clearances to .009" and all exhaust clearances to .011". I'm crossing my fingers that the next compression test comes out better than what I posted before. I'll find time to do that this week and record my findings.
https://cimg5.ibsrv.net/gimg/www.s2k...1af7e179d.jpeg |
I did mine last week, my figure was uniform 220 across all four. I did it cold, worried about removing plugs from a warm engine.
The 2nd round I accidentally cranked a few seconds more at cylinder 4 and get 245, did you crank it evenly? |
Engine should be warm. I crank until the gauge stops increasing.
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It will be interesting to see the next compression test results. I'll be surprised if the tight valves explain the compression test results. We shall see.
What did the plugs look like? What kind of oil consumption do you see with the engine? |
Originally Posted by rpg51
(Post 24519413)
It will be interesting to see the next compression test results. I'll be surprised if the tight valves explain the compression test results. We shall see.
What did the plugs look like? What kind of oil consumption do you see with the engine? |
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