Compression is it my rings or my camshaft timing chain is fine no metal filings in the oil

Asked by Jul 17, 2017 at 01:07 PM about the 2002 GMC Sonoma SLS Ext Cab 2WD

Question type: Maintenance & Repair

Did cold crank compression test with my mechanic
receiving 90 95 90 on 3 cylinders receiving 116 PSI
on the 4th cylinder have not performed a wet test
yet pulled the timing cover timing chain looks
excellent timing marks line up trying to avoid a
total teardown started out with no spark changed
everything ECM ignition module coil packs crank
sensor cam sensor heater sensor even had the
ECM flashed found a broken power lead to ignition
module connector repaired now with spark to the
spark plugs but terrible compression I would say
I'm pulling my hair out but I'm bald so I'm kicking
myself in the ass instead 1700 haven't found the
problem

1 Answer

91,415

Most likely worn out rings but I suppose it could also be valves that are burnt.

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