When I unplugged, motor revved higher. I don't think my problem is vacuum.

Found half the problem....injector #6 wasn't firing right. Pulled it and it was clogged. Replaced with another I had laying around. Ran much better. Still a slight hiccup though. Did a compression test....ugh. Low.

1. 60
2. 60
3. 90

I stopped there. Too mad to continue. Pulled spark plug and replaced with tester. Let motor idle and took the reading.

If your compression readings are that bad. I think it time to try a wet compression test but it looks like you will be pulling the engine back out again. Hopefully you 30 day warranty didn't expire already.

I know. And yes, the warranty already expired. I have the old block...which I think is still good. But I can't be sure and have no way to compression test since there is no head installed.

As pointed out earlier...there was a good bit of oil in the intake which indicates blow by it believe. Didn't know enough at the time to realize that was a big problem. I'm half hoping I did the compression test wrong and that's why. But, I don't think so....

Here is the plan for today.

Pull all spark plugs and disconnect fuel pump relay. Dry test all cylinders. Record results. Wet test all cylinders. Record results. Perform leak down test putting each cylinder at TDC and pump 75psi into cylinder and listen for air. My luck and I'll be sure to confirm this thing is shot....again.

This will be the third motor I've installed in this thing. Over a year and I don't have it running. On top of this, it needs calipers, I think every bushing, and new shocks. Damn good looking jeep and I wanted to save it. I've got a pile of money in this thing and I'm waay to hard headed to give up and scrap it. Just had an offer to buy it for 1500 as it sits. Tempting...but, I can't do it.

Just bought a new smittybilt xrc bumper and 12k winch for it....ugh. Fml.

Note to self...compression test before you install a new motor. And thank you guys for being willing to help and answer my questions. What looked to be a cheap fix for a new toy turned into a nightmare. I have plans for some other aesthetic upgrades and a pile of lights...but,I'm afraid to go that far where I'm at currently. Could all be a waste.

Talk some sense into me?

I feel for you! I know it must be frustrating doing all of that work and having to start from square one.

At this point, I guess I would yank it out and have it rebuilt. If, as it sounds like, you are going to keep the Jeep.

If you just potshot around on this, it will be an endless source of frustration. Like it already is.

Rebuild it and go on down the road. Sounds like you have enough engine parts laying around to make up a good one.

True. That was the next step. But, might not be needed.

Turns out I had a faulty compression gauge. The check valve inside was letting pressure leak back down. I exchanged for a different model. Let the car get up to operating temp and performed the compression test. 5 motor revolutions on all tests.

1. 131
2. 126
3. 130
4. 131
5. 124
6. 114

I retested No. 6 after putting a little trans fluid in and it brought it up to about 125. Bad rings here. But, not terrible. I won't rebuild for these numbers. It should run well.

Back to the drawing board again. It's still a little rough at idle. If I hold it at 2500 rpms I can't notice it. Only on idle. Maybe I'm crazy...but, I don't think so.

Thoughts?

I just cleaned the idle air control sensor and the throttle body. Thought I had it fixed and that it ran well. Noticed rpms at about 1000. Realized I hadn't plugged in throttle position sensor or iac sensor yet. Did that and idle went down to about 600. Still a little rough. Ran it for about 30 seconds. Need it cool off so I can put coolant instead of water. Gonna do that, disconnect battery, and possibly replace iac and tps sensors.

pull injector harnesses one at a time and see if the idle quality worsens or stays the same. maybe the #6 you replaced wasnt the only bad one?

Did that. All affected idle. However, some not as much as others.

Looks like it's wise to get a second opinion when using a compression tester.