I have a 2001 jeep cherokee sport with roughly 105,000 miles on it, recently the compression gauge before you start the engine goes almost the middle (40), it use to be exactly at zero when you put the key to the ''on position'' now when i start it, it shoots up to 80, but the engine sounds, and feels fine, everything runs the same...so what do i need to replace, there is no CEL light or anything, just the gauge is outta wack, i have re calibrated the gauges by holding the spedo button and letting it cycle throught it's test. still nothing
Generally it turns outto be one of three things 1. bad sending unit (switch) 2. stuck pressure relief valve in pump (not often) 3. bad gauge head (less than not often)(rare). You can attach a mechanical gauge to the engine and read actual oil pressure (attaches right where sender screws in). That will tell you if the problem is inside the engine or in the gauge system. If it turns out to be inside the engine you can add Marvel oil...many times the problem will clear up in a few days.
Be aware though that very high pressures can cause the oil filter to split or the seal to leak.Most quality filters are tested to about 100psi.(no idea about cheap ones if the test them at all)
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or oil pressure gauge
yes sorry i meant oil presure gauge reads 30 before engine starts, wen engine is started it shoots too 80, but everything sounds and drives normal...maybe a bad Oil Pressure Switch????
yes sorry i meant oil presure gauge reads 30 before engine starts, wen engine is started it shoots too 80, but everything sounds and drives normal...maybe a bad Oil Pressure Switch????
il have to look into getting a oil guage to test the actual engine. i'm leading to think your right about the switch, because whnen the key is put to the on position before engine is started, it already gives a reading, never use to do this, it would read exactly at zero til the engine started....
Compression relates to pressure inside the cylinders...are you talking about oil pressure???
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