Compression??

Well I finally broke down and bought a compression tester and tested the compression in the jeep and these are the stats. Cylinder 1: 116, Cylinder 2: 129, Cylinder 3: 120, Cylinder 4: 125, Cylinder 5: 129, Cylinder 6: 120. How do those numbers look, cause I have no clue on a jeep. I have an 88 wagoneer limited with a MPI 4.0.

All pretty much the same, above the minimums. Did you pull all the plugs during the test or one at a time? Not a bad idea to blow out the spark plug wells before a compression test, so junk doesn´t fall (or get sucked) into the cylinders.
Numbers are Usually a little higher, with all the plugs removed and a good fully charged battery. Also a little higher with fresh or newly changed oil.

Yeah I pulled all the plugs and I blew out the plug wells.

TBLimited said:

Yeah I pulled all the plugs and I blew out the plug wells.

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Those numbers look okay to me. The thing is to not trust the absolute reading of a gauge as much as the difference between cylinders. #1 seems a little low compared to #2 & #5.

But, was the engine warm and did you hold the throttle plate open while cranking the engine? The latter is easily overlooked and will affect the test.

I'm trying to diagnose a problem because it won't start so no I couldn't start and run it. Yes I did hold open the throttle plate while cranking.