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-   -   Compression/ buring oil (https://www.cherokeeforum.com/f2/compression-buring-oil-135136/)

93 2dr cherokee 05-09-2012 06:44 PM

Compression/ buring oil
 
1993 Inline 6 auto 124,000 miles. Burning oil did a comresion test front and back cylinder were 130psi all the others were 135psi verying 1-2 psi. the front cycilinder took alot of time to get the pressure had to turn it over way more than the others. valves or valve guides why im buring oil? Also my spark plugs were pretty bad so any certain brand that is good? thanks

Willys55 05-09-2012 06:51 PM

Do the test over again, the test is only good for diagnosis when you "puff" each cylinder with the same number of revolutions, but it sounds like you may have a burned valve.

JeepingDan 05-09-2012 06:57 PM

Champion coppers work really good and X2 with Willys on same ratio. One or 2 turns should be more accurate.
Also do a leak down by compressing air into each cylinder each one on compression stroke. Then you will be able to hear in any air is rushing out of the intake or exhaust.

rrich 05-09-2012 09:43 PM

If the plugs were really bad, put in the new ones and drive it 100 miles, test again.

Bad plugs can make you think there's a compression problem when there isn't.

To get significant readings:
ALL PLUGS OUT
THROTTLE BLOCKED OPEN
SAME NUMBER OF PULSES EACH CYLINDER

If one is LO - shoot 3 squirts of engine oil in the hole, rotate engine 3 times to spread the oil, test again

if comes up to normal, rings, if not, valves.

do a leak down test before panicking.


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