Slartibartfast

51 is injector circuit, not ignition. Means there's an open circuit on an injector. If the #5 injector came out in pieces (I assume that's what you meant with the thing about the spark plug?) then that's where I'd start looking. You can check across its pins for resistance.

Yeah, getting an early EFI past smog does not sound like fun. If it's just the can that's rotten, and the moving parts are still alright, I'd just pull the can out, clean up the worst of the rot, and then patch the hole with something. You could weld/braze/solder, but I'd be concerned about messing up the rest of the assembly (unless that cover comes off easily). I'll bet you could get away with covering a small hole with epoxy putty, JB weld, Bondo, something like that. Cut a piece of a can if you need to cover a big hole. I hadn't seen the filter in there! Definitely give that a good clean (or a new one if it's available) while it's open.

The '89 manual shows that as an "A.I.V. Box (For Hot A.I.V.)." It connects to the exhaust system and to manifold vacuum, so if it's rusted through at the bottom, it could be allowing unmetered air into the intake manifold (raising the idle and screwing up your fuel mixture). The anti-backfire valve is supposed to dump air into the intake when there's too much vacuum (apparently the suction on deceleration pulls too much fuel through the injectors and makes the engine run pig rich and backfire otherwise). Looks like if you take the air filter out, there's a small pipe to the driver's front of the throttle body, coming up through the bottom plate of the air cleaner. Cover the end with your finger, rev to 3k, then let the throttle snap shut and you should feel a little suction from that port. If you feel suction, the valve is working. If the AIV and AB share a vacuum feed, and the AIV is leaking air into that feed, the AB valve wouldn't see full manifold vacuum and so wouldn't do its job.

Unplugging the ABS brick (not really a pump, it's just two solenoids and an accumulator in there) would open-circuit both solenoids, which would keep the light on. Wouldn't surprise me if they moved the module around between years. (I don't have an FSM between '89 and '94 to confirm.) If they originally had it in front of the shifters, but relo'd it to clear something, it was probably the ducting for the optional rear passenger footwell vents. I don't think the US-market WD21 ever came with airbags. I wish I had an update on mine, but I don't.

Ah, I see what you're after now. I don't think I've seen anyone drop the lower links. Some people build custom adjustable-length links to push the axle back a little after the lift, but I don't think that's required for the 2-3" Jeep spring lift.

There are five suspension links attached to the rear axle. Two upper links and two lower links (in front of the axle) keep the axle from moving fore/aft or wrapping, and the panhard rod or track bar (behind the axle) prevents it from walking out sideways. The panhard rod should be pretty much level with the axle. When you lift the truck, it goes off-angle and pulls the axle to one side. Dropping the panhard bracket puts the axle back where it's supposed to be.

Took it to a different shop. Got a call this morning that they'd managed to get some air out of the system and thought they were done. Pedal still bottoms out and the rear brakes still do nothing, so, no, they're not. They had another look and determined that the rear disks are doing less than the e-brake, which is saying something given how clapped my e-brake is. They're going to keep digging.

Looking at the service manual, there should just be a lock pin with a nut, washer, and spring washer holding it on. Wouldn't be surprised if it's a little seized up.

Alkorahil hasn't been on here for a few years, unfortunately. This diagram and parts list is probably what you're after, though.

I think I just got lucky with the vise grips when I did mine. You might try grabbing the washers behind the hex with the grips rather than grabbing the part that sticks through the far side of the glass.

Booster came out (easier with the alarm siren removed). Nothing obviously broken, not that I've had a good one on the bench to test against. The master-side pushrod adjuster is frozen up, but seems fairly close to where it should be (and I can't come up with how that adjustment would've gotten screwed up by a caliper replacement), so I put it back together. I adjusted the rod from the booster to the pedal, re-bled the master, and installed it with plugs so I could test it on its own. Press the pedal and it's the same three inches of squish with all three ports blocked off, so that's got me back to thinking the master ain't right. Third one in a row tells me it's probably me screwing something up rather than bad parts. I've watched a bunch of videos on bleeding masters and all these guys with old American cast-iron stuff make it look easy. I don't know if I'm an idiot who can't bleed brakes or if whoever designed these master cylinders was dumped by a mechanic once and swore vengeance, but holy crap this is not going well. I couldn't make it do jack with the hoses this new one came with at first, so I used the plugs, bled it as far as that would go, swapped on the hoses, got a bunch more air out, let it sit, pumped a little more clear fluid through it, then installed the thing, bled it, bled all four corners and the ABS, hit the pedal and it feels exactly the same. Also, the master's making squelching noises now, so either the bleed didn't work somehow or air bubbled back into the master when I reconnected the lines. I'm half tempted to try the half-ton Chevy MC swap. (Anyone still around who's tried this?) I'd rather not make this into a science project, but if the stock master's really this hard to get air out of, I'm inclined to rip it out and get rid of the bloody thing before it takes what's left of my sanity.

New master came today. Cardone 11-2585, which the Rockauto catalog says is correct for four-wheel disk. The picture on Amazon showed a reworked factory casting, but of course that's not what I got. The new one came in a Cardone box with the right PN on it, but is clearly a new aftermarket part. It looks almost exactly like the last one, right down to having "AB-36" cast into the side (though it is in a different place). I bled it (the hoses they include for this are useless, so I went back to plugs), installed it, did some bleeding, and the pedal feels exactly the same as before. Either I've bought another defective or incorrect master cylinder, or the master cylinder was never the problem. I stumbled on this a while ago and thought, nah, can't be that. I'm running out of ideas and I'm sick and tired of brake fluid, so tomorrow, the booster's coming off, and I'm going to shake it and see if pieces fall out.

The trans jumping to third indicates limp mode. If you turn the ignition off, then on again, does the "power" light on the dash flash? That's how the trans computer outputs trouble codes. High idle could be a vacuum leak. What have you replaced so far?

Yep, that was a Red Green reference. Used to watch his show when I was a kid.

Well, it didn't go badly, but it didn't go well, either. No bubbles. I can still get a three-inch stroke out of the pedal with the engine off. My dad asked if it was the correct master, so I checked the Amazon again. It says "this part fits your vehicle!" but (like most listings on Amazon, or eBay, or even some of the parts on Rockauto) they don't say if it's for rear disk or rear drum. I looked up the Dorman PN (Dorman M39976) on Fleabay and found a listing with interchange PNs, including Nissan PN 4601092G01, which factorynissanparts lists as the drum master. The disc master is 4601006P02. So, yes, it's very much the wrong damn master. Master cylinder number three (Cardone 11-2585, listed for 4-wheel disk on Rockauto) should be here Friday.

Where does the manual show that bleed order? BR-3 of the '95 manual says to bleed the LSV (if equipped, which mine isn't), LR, RR, LF, RF, ABS. The '89 manual shows the same except no ABS block. This doesn't make a whole lot of sense to me but that's the sequence I gravity-bled it in. And yes, the calipers are on the correct sides, with the bleeders on top. The issue started when I replaced the calipers, which is why I doubt air in the rear system was the original problem (although who knows at this point). I tried blocking things off tonight and got nowhere. Clamped off driver's front, passenger's front, no change in pedal squish. I undid the line going into the ABS block, threaded it into an old soft line, bled the line, and crimped that off. Still spongy. So I know the problem here isn't the calipers, the hoses, the ABS block, or anything from the ABS block back. All it can be at this point is a buggered master or air in the hard lines. Looking at the hard lines, two of the three come out of the master and then go up higher than the res and across the firewall before going down again. If air got into those lines when I did the calipers (or during my monkey vs football experience with the first MC), I doubt my gravity-bleeding flowed nearly enough volume to move that much air all the way down to the bleeders. I've watched the fluid in the clear hose while bleeding, and it can and does flow around larger air bubbles if it's not flowing fast enough to carry them away. This has me looking into reverse-bleeding. It seems logical to push the bubbles out the hole they're already close to rather than fighting them all the way down. It seems less logical to dump $200 on a commercial kit. I have a pasta sauce jar, shop air, a regulator, some vinyl hose, and the handyman's secret weapon, duct tape. This can only go well.

Ah, I missed that the sheath was buggered. Makes sense. Not something you want to deal with on the side of the road.

If you're shifting the manual transfer between 2H/4H/4LO at a stop, then no, it won't care if the hubs are locked. I wouldn't be surprised if you were able to force the transfer to catch 4x with the hubs unlocked at low speeds, but I don't understand why you would. You have to stop to lock the hubs anyway, right? And yes, 4LO with the hubs unlocked (2LO basically) is great when you need a little more control. Great for backing trailers. It's also helpful for controlling wheel spin if you're having trouble with traction but don't want to get out and deal with the hubs. I didn't mention it here because I assume the computer for the ATX14A would see that front wheel speed != rear wheel speed when the clutch is locked and start throwing codes.

Reintroducing worries, that's what I'm here for! If it's any consolation, the manual-transfer trucks have a bit of the same worry. If you're driving in 2H with the hubs unlocked, and try to engage 4x, it'll make a nasty grinding noise like you're trying to shift a manual without the clutch. With failing auto hubs, I never knew whether the front end was spinning or not, which made going for 4x while moving a little nerve-wracking and often hard on the transfer. I don't think I've barked it once since switching to manual hubs. (I leave my hubs locked all winter, anyway, which is 95% of when I need 4x around here.)

I removed the seat, unplugged the ABS brain, and found the two solenoid wires side by side at one end of the plug. The isolation solenoid has a light green wire with a red stripe and the dump solenoid has a grey wire with a red stripe. Both ground to the chassis somewhere. Both ohm out close to what the FSM says they should be. Both click when given 12v. If I press the pedal, engine off, and then energize the dump solenoid (which opens a path to the accumulator to relieve brake pressure), the pedal falls. This means the dump is working properly and isn't jammed open like I thought it was. If I energize the isolation solenoid (which cuts off the rear brakes from the master), press the pedal, and then release the iso, the pedal falls a little as fluid enters the rear brakes. The pedal is not hard with the iso on, and doesn't fall far when it opens, so clearly the problem is upstream of the iso. If there's air between the inlet and the iso, I might be able to bleed that by cracking the fitting going into the ABS block, or test it by removing the fitting and capping it to see if the pedal improves. Seems like a long shot. I'm also not sure how air would've gotten that far back just from installing and bleeding the fronts. Perhaps there is something wrong with the front calipers. Installing them started this mess. Perhaps the prop valve in the master is waiting for a certain pressure in the front brake circuit before it provides jack crap to the rears, and I'm running out of pedal stroke before the fronts pressurize, which is why the rear system's getting dick-all. The driver's side caliper (wiggly though it is) is probably not the problem, or at least not the whole problem, given that swapping the stock one back in changed nothing. I don't have the hooped passenger's side one to re-test with (sent back as a core), but I do have bleed plugs, so I could block off that side and see if the pedal changes. Come to think of it, some weird crap came out of that caliper when I first bled it. Looked like dirty lumpy (but not rusty) bubbles, but they weren't air bubbles. I assumed it was some kind of assembly lube. There wasn't much and it quit coming out pretty quick, but it makes me wonder what might be in there now.

I doubt it would soften tip-in enough to matter, but it might reduce the shock load trying to stretch the cable if the throttle body hits its stop before the pedal does. For $90 I still would've used a zip tie but either way, good to see you got it!

Didn't get to it last night. Planning on screwing with it tonight and figuring out the size of fittings I'll need to delete the ABS if it comes to that.

As MJO said, run only 2HI with the hubs unlocked. If the hubs aren't locked, the front drivetrain isn't spinning, and the computer doesn't know this. If you're driving at speed and Auto mode decides to engage the clutch, it thinks it's coupling two rapidly spinning shafts together, not coupling one rapidly spinning shaft to a stationary one. I don't know how much damage this would do, but it's unnecessary wear at best, and I imagine it would confuse the hell out of the computer.

The mechanic couldn't figure it out either, so this turd's back in my punch bowl. I'll throw some power at the solenoids tonight.

I remember that one! No fuel hose here, though. Soft lines are new. The ABS block looks like a simple enough circuit, just two solenoids with a shared ground. My only reservation with digging into it is that I'm not sure the solenoids take 12v. I mean, I assume they do, but I don't want to bleed smoke from the lines instead of air. BR-46 suggests I should see 0.3-3.5v at the connector when the module's doing its self-test, but I assume that's the logic checking for the correct resistance rather than actually cycling the solenoids. Anyway, it's got an appointment with a professional this morning. Sounds like they've dealt with this kind of crap before. If they figure it out, I'll ask what the hell they did. If they don't, I'll throw 12v from a drill battery at it and see how it likes that.