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Old 12-30-2007, 03:18 PM   #1
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compression?

I have a 94 with 4 cyl. manual trans. It has been running kind of rough and I have been through all of the sensors and senders but with no improvement. I decided to do a compression test. #1 reads 110 lbs. 2#, 3# & 4# all read 155 lbs. I then retested all cylinders and got the same results. After squirting some oil into #1, I tested it again and got the pressure to come up to 160 lbs. Is it correct to assume that this is a piston or ring problem? How much pressure differential is acceptable between the worst and best cylinders?
Thanks in adevance for any help you can pass along!

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Old 12-30-2007, 04:16 PM   #2
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so is it running any better now that they are all even? if not then it might not be a ring problem...

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Old 12-30-2007, 05:55 PM   #3
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usually if oil increases your compression it is a ring problem. the fact that it is giving 110 though doesnt sound like a broken ring. i think the rule is 10% differential is acceptable but i cant remember right off. you may consider pulling the head to see if maybe you burned a valve on #1 maybe?
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Old 12-30-2007, 06:09 PM   #4
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well the fact that it is giving off 110 could definitely be a ring problem, but do a leak down test to find out more
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