Slartibartfast

Yikes, that sucks. I did a little research to see if I could find a part # to cross-reference but didn't find much--it doesn't look like it's a part commonly sold on its own. The only other thing I can think of is to download the AT sections of the service manuals for the HB and the X and see if the pumps look the same, mount the same... my understanding is that the later transmissions were improved somehow, but I don't know the specifics. Hopefully they didn't screw with the pump design.

It looks like the Z24 oil pump is driven by the distributor, so if the distributor isn't seated properly, the oil pump won't work. I dealt with a similar setup on a friend's Chevy and had a hell of a time getting the pump and the distributor to line up. Could be an easy fix, assuming the bearings have survived being run this far w/o oil. Looks like you could bench test the pump by sticking the pickup in a cup of oil and turning the drive bit with a cut-off screwdriver like the guy in the video used, or a whittled down pencil for that matter. If no oil comes out, and the pump isn't obviously coughing up pieces of itself, I'd check the pickup screen for any obvious clogging and see if the pump is sealed to the pickup properly. If there's a missing gasket in there it could be sucking air instead of oil. Sorry to hear you had to pull the motor again!

+1 on the loss of power question, slipping or bogging? Very important to nailing this down. When you gas it in high range, when it doesn't move, does it rev freely like it's in neutral or does it act like it's under load? And yet another question to see if my pet theory has legs... if you start the engine with the transfer in 2H or 4H, let it sit for a minute, and then go for 4LO, can you make the shift or does it grind like you had it in neutral for too long?

Bad lifter maybe? Not the end of the world if that's the case.

+1 for shims, given that you're looking at it and seeing camber. I've heard the UCA bolts won't hold tension if you've got too thick a stack of shims. Bolts work loose, shims fall out, and you're a backwards hat and some stickers short of hellaflush.

Ah, that makes sense, I remember reading that the throttle body injection system doesn't mix properly or something without the air cleaner buttoned up.

I don't think it could light both, not with factory wiring anyway. The two headlights have completely separate wiring all the way to the switch (and separate contacts inside), and the fog light signal wire only taps into one of them. If positive shorted to signal inside the relay, you could get one light coming on, but unless the harness has been modified or the switch is faulty, I don't think it would do both.

Two low compression cylinders next to each other makes me wonder if there's a leak between them. If it's not the pump, or the sender, you could have a blockage in the system or the bearings could be too worn to hold oil.

I popped the ones out of my '95 ages ago and yes, there is a tiny slit in each one. I enlarged the slit on mine slightly by cutting the baffle looking deal off the back. Even then, I suspect more air gets into the engine bay through the hood gaps.

Yep, it's the tube oil goes through to get to the pump. I wouldn't call it a common issue, but if your sump looks like the la brea tar pits, it's going to stop something up. Doesn't sound likely on your engine though given your description of the oil. I suspect your knock sensor code means your knock sensor is working properly and picking up all the clattering that an engine with no oil pressure makes.

Looks like a clean rig! Hopefully that frame isn't as bad as it looks. The ticking could be a lifter or (most likely) the classic exhaust leaks. The thing I would do first, assuming the frame checks out, is the timing belt. The change interval's about 100k and if yours hasn't been done, it's close on miles and old enough to drink besides. I did the belt on my '93 after I brought it home because I didn't know when it had been done last and I didn't want to gamble with an interference motor.

Your diagnosis sounds logical to me. Not a common problem but the only alternative I can think of is the pickup tube getting blocked. Bad timing could cause the loss of power but wouldn't explain the noise or the oil light coming on.

The VG33 swap is common and fairly well documented. The trouble with lift kits on these is that the IFS isn't really built to take it. That's not to say they can't be lifted, just that it'll take upgrading a few things for it to hold together afterwards. I'd say get the motor sorted, wheel it a bit, see how you like that, and then decide what needs upgrading.

The fog light relay only ties into one headlight's low beam, and you're having both stay on. This makes me suspect it's a symptom of the low beams staying on rather than the cause (unless your headlight harness has been modified). What I would do is unplug the headlight switch and see if that makes the stubborn lights go out. If it does, pull the back off again, cycle the control stick around, and see if all the contacts are opening like they should. If the contacts for the low beam are bent up, the throw they get from the switch might not be enough to open them, but it sounds like they were doing this before you opened the switch. That makes me wonder if the mechanism that moves those contacts is broken or jammed up. I haven't heard of one failing like that but it's about all I can think of. If the lights don't go out with the switch removed, then you're in for a whole other round of fun.

Bolted together but they don't share fluids. Changing the tcase fluid in my '95 solved the issue it had where it would stick in 4x. I did the fluid on my '93 when I got it just to get ahead of it. It's a little tricky getting fluid to the fill plug, but not too bad if you've got a transfer pump or if you can rig up a bottle, some tubing, and compressed air to push the fluid up into the case.

Shot in the dark here, you had to drain some coolant to pull the manifold, right? Did you bleed the air out of it afterwards? If the cooling system has a big bubble at the top, that could be making it act a little weird, especially if any of the temp sensors are in that air bubble. I know the VGs have a bleed screw on the manifold. The L/C section of the service manual is where I'd start looking for how to bleed the VQ.

In the second pic from the bottom I'm seeing an oil blotch not connected to the rest. Makes me wonder if the oil is coming from somewhere else.

I've read about people pinning them as a trail fix. Makes more noise, wastes more power, but probably fine to get you home.

You might also check for signs of rodents, especially in the air filter box. My '93 had a rat's nest in there that plugged the MAF screen when the engine ran.

I'd do the vac lines and look possible issues with the intake gasket. Any codes? IIRC there's some kind of idle relearn thing you could try as well, should be in the service manual. Too bad about the valve screws. Hopefully the missing ones found their way back out without doing too much damage.

^Good question on how it lost power--that could tell us a lot. Assuming it bogged down... it could be torque bind, but only if you were driving in 4H on the highway or it somehow popped in or failed to disengage from the last time you used it. You might try jacking up a front wheel to see if the wheel turns a little as it loses contact with the ground, try to turn by hand to see if the hub is locked, then try driving it again to see if that changed anything. I have heard of the transfer case chain breaking and getting jammed between one of the sprockets and the case, but IIRC that leads to it completely locking the output against the case, and I don't think that failure would've made it to the parking lot. Unless it swerved when it lost power we can probably rule out anything in the front end. You might have a look at your rear brakes to be sure they're not locked. I would also check the fluid in the transfer case and the rear end if you can on the off chance one of them ran empty and burned up. I remember someone on here who accidentally ran his dry and burned it up.

That looks like your fog light harness. Probably easiest to just scab in some new wire where it's damaged. I can see why you wanted to flush it now! That's nasty in there. I hadn't heard of the rice trick, I just used a handful of gravel when I cleaned out my overflow.

I know mine does.

My (very limited) understanding of this problem is that the sensor itself leaks where the wiring passes through, and the fluid just follows the wiring down.

Yep, the contacts can be a little finicky. When I did the switch in my '95 (and took that picture!) it took a little monkeying around to get everything back to normal. I just kept tweaking the strips until they all moved properly. IIRC when I cleaned the one in my '93 I put a piece of 800 grit or so between the contacts, closed the contacts by moving the switch, then pulled the sandpaper out (and repeated as needed) and didn't have to screw around with readjusting. When the contacts come together, the light they attach to comes on. You shouldn't have more than three making contact at once. I haven't heard of one sticking closed (usually they fail open, that is, light won't turn on because the contacts are fouled) but the switch would've been my first stop too. I'm not sure what else in the circuit would be keeping the headlights on unless you have DRLs. If you unplug the switch, the lights should go out. I'm not sure what would cause it to fail closed, but my suspicion (if adjustment doesn't sort it out) would be something stuck in the mechanism inside. I didn't tear into mine that far so I'm no help there. If you unplug it and the lights don't go out, well, you're in for some fun tracking that one down. These trucks don't come with headlight relays, so the switch carries full power. The wires from the switch to the lights are +, and the lights are grounded to the chassis (-). A short to ground from the + side would blow a fuse, not keep a headlight on; it would have to be a bare + wire from something else touching the headlight wire, which would surprise me.