Slartibartfast

NTB93-036 covers the car alarm. Annoyingly it didn't make its way into the service manual, as the security system was installed at the port, not the factory. I think I downloaded it off Nicoclub a while back, but I can't be arsed to dig it up again, so here it is on Dropbox. The rest of the lock system is in the BF section of the manual, which you can get from Nicoclub ('94/'95 round dash) or cardiagn.com ('90 square dash). There's a short-ish harness from the alarm brain to the door lock wiring, and it plugs in behind the driver's kick panel or thereabouts (I think it's intercepting the power lock wiring for the driver's door). Sounds like either the alarm brain is borked or there's an open circuit between it and the door harness. Good luck!

Is there any correlation between the noise and the speed of the engine, or how many electrical loads you're running? Absent any better ideas, I would unplug the alternator (or remove its belt) and see if that kills the noise. The alt makes 3-phase AC and the diodes inside rectify that to DC, so if one of the diodes goes out, the alt could be dumping all kinds of noise into the electrical system.

I used the races on mine. Did seem a little loose, but the bushing sorta filled it once it squished down. Yours looks like a better fit. Is it a custom piece or a repurposed off-the-shelf?

Looks like a good list. Look into the missing link if you haven't, supposedly that keeps the front end a little tighter. I'd leave the fenders alone until you know how where/how much the tires rub. If it's got an automatic, add a cooler. If it's got 4.3 gearing, you can offset your larger tires by swapping in 4.6. If it's got the rear LSD, check out Hawairish's writeup on packing that for higher breakaway torque.

If you can find a replacement remote, then yes, you can program it in. The alarm/keyless entry brain is under the driver's seat. It's the square one with the hole in the middle, which may still be hidden by a sticker if nobody's been in there yet. Under that hole, there's a square button. Turn the key switch on, then off. Press and hold the button on the brain. The siren will make four single blips, then five in a row. Release the button and it'll beep again, prompting you to press the large button on the remote. When it beeps again, press the button on your second remote, if you have one. It's got four memory slots and the TSB recommends filling them all for some reason, even if that means programming one or two remotes multiple times. When all four slots are filled, turn the key switch on and off again. Then try locking and unlocking the doors from the remote to see if it worked. If you want the full instructions and a circuit diagram, track down NTB93-036. I think I downloaded it off Nicoclub a while back. If you don't find one, message me and I'll shoot you a link through Dropbox. That said, you might be happier with a modern system. I deleted the alarm brain from mine because I was tired of accidentally setting it off, and later removed the wiring harness as well because a loose connection somewhere was playing silly buggers with my starter circuit. The alarm system on these was a port-installed afterthought, so it's pretty easy to remove.

Does anyone else smell canned pork?

I have no idea, but I would check your work inside the hatch first in case something just didn't clip in properly and worked loose. If it thinks the hatch glass is open, maybe that cancels arming the alarm?

Alvarez Metal Works on Youtube posted a video on tearing down a door, looks like he only showed the front door though. I would expect the linkage to be similar. I've got a donor I'm stripping down and can get pictures if needed. The bent end of the linkage rod goes into the hole in the base of the clip, and then the clip pivots around to grab the rod and hold it in. To disengage, find the open end of the clip (so you know which way to push) and work it off of the rod, and then pull the rod out of the hole. As for which to remove first, if you can get to the clips, I'd get the rods off first so the latch isn't flopping around while you fight with the clips. Take pictures of how it's all set up before you start so you don't get all turned around when you go to put it back together. Hopefully the fault with the lock is something simple, which will make itself obvious once you've got it on the bench.

EL-213 in the '97 manual says it'll take up to four. The same page also has the procedure for programming new remotes. If the last person to program the system programmed in more than two remotes, reprogramming it with just yours would make it forget the other codes. If that doesn't do it, you might try programming in just one remote at a time, to see if one of them has a doppelganger in the neighborhood. I would hope the OE remotes all had different codes, but who knows how the aftermarket remotes are set up. Or I guess you could walk around the block with your remotes, pressing the panic button on one, then the other, by every late '90s/early '00s Nissan you pass, until you set off someone's car alarm. Might not be the best way to make friends. That said, it might not be the remotes at all. WD21s are well known for their door locks triggering randomly as they get older. I don't know if R50s do the same thing, but I would not be surprised. If you catch it in the act of locking itself, note whether the corner lights flash at the same time. If the R50 works like the WD21, the lights flash if you lock it with the remote, but not if you trigger the locks manually. If the lights don't flash, you may have an electrical gremlin rather than someone stepping on your remote codes.

Security cert/connection not private warning fixed here!

I think I did the belt at around 230k miles, and it passed 250 recently with no issues. I did have the timing together and apart a few times before I was happy with it, both because I couldn't convince myself I hadn't set it too tight and because I didn't replace the crank seal the first time around and it started leaking as soon as I buttoned it back up. I wasn't impressed by the tutorial's 90° tension check, but I figured it would get me closer than I'd get screwing around with improvised shims and a fish scale. Not sure why your tension isn't meeting spec. It shouldn't need to be maxxed out on the tensioner, and you don't want to set the belt too tight. I think I used a Gates belt on mine too and found no fault with it. Do you have a link to the tester you're using, and have you checked it against a known weight to make sure it's reading right?

The service manual has an elaborate method involving shims and weights. I used the method in this tutorial instead.

With the engine out. I did the timing belt on my VG30 with the engine in, and it's not terrible, but given the opportunity, I'm doing it when it's easy. I was thinking more of the accessory drive belts.

Yeah, it's a pain, but it is possible. The trick for the driver's side plug wires is getting the angle right. IIRC I found some angle to where I could see the plug between runners, or got a finger down in there and found it by braille, and went from there. It's not fun, but I've worked on worse. That said, I intend to do everything but tension the belts on my VG33 before I put the engine in the truck.

Doesn't even have to be running. Key on, engine off. Press the pedal slowly. The number should rise as the pedal goes down, then fall as you let off. If the number bounces around with little regard to where the pedal is, or drops/spikes randomly, the sensor is borked. Think of it like the volume knob on a stereo. If it's good, the volume goes up and down when you turn the knob. If it's bad, it pops and crackles and drops out if you stop in the wrong spot. Don't condemn the sensor if it doesn't go all the way to 100%. I've seen that on other vehicles and it wasn't causing problems, so I left it alone. Unless you damaged the sensor or its wiring while you had the intake apart, I doubt this'll end up being the issue, but (if you have the tool) it's an easy thing to try. And yeah, I hear you on "I won't let this wore-out POS die on me now." I've been there with mine. Actually I'm kinda still there. Good luck!

Well, that sucks. I wouldn't expect a break-in or relearn or any of that--though you might try resetting the computer on the off chance the computer got confused when the fluid was overfilled. I remember punching some kind of Konami code into my dad's '03 to reset the engine computer (following instructions in the service manual), but just unhooking the battery for a while would probably do the same thing. Long shot, though. Running it when it's not shifting right might cause damage depending on what the problem is. The transmission is an RE4R01A. The AT section of the service manual has a bunch of troubleshooting in it, though naturally they assume you've got Consult. They were also used in Skylines, so there is some 3rd party info out there as well. (Serious rabbit hole advisory on that link, BTW.) Short-shifting makes me think it may be getting bad info from the engine computer. Maybe the same bad info is why the engine is running poorly. If you've got a code scanner that will show live data, I would take a look at the data from the throttle position sensor. See if the % jumps around when you open/close the throttle slowly. IIRC there's a sensor at the top of the bellhousing that reads engine speed off the flywheel teeth, or something like that? I only remember it as something that's on the Xterra trans that you don't use if swapping it into a WD21. But that's something you could've unhooked when prepping to drop the trans, then missed when buttoning it up (or bumped the sensor out of position or something). Given that this issue started when you messed with the transmission, I would check that you got everything buttoned back up properly. (That goes for any sensors/wiring you moved to pull the plenum, too.)

Looks like the 240 guys have a Honda motor they like. Might be inspiration if nothing else.

I've heard of people swapping in the intermittent wipers on older/base model rigs that didn't come with them, but hot-rodding the actual motor is news to me. Mine has always seemed plenty strong to me. It'll stall if the blades are frozen down or trapped by snow, but in that case I suspect more torque would just break something. If yours feel weak, I would check for voltage drop (weak switch or wiring), dry bearings/pivots, hard grease in the motor--basically go over it looking for something seized or gummed up or otherwise sapping power. With a little fabrication, and some wiring, I imagine you could get most any wiper motor to work. The wiring could be tricky depending on how the donor was set up. Some wiper motors have high/low/ground wires, some are case-grounded, and some are ground-switched. And then there's the wiring for the self-parking and the intermittent function, if yours has that.

Right in front of my eyes! No wonder I couldn't find it.

The throttle position sensor is one of the inputs the trans computer uses to decide when to shift. I think that's how it decides how hard to shift, too.

+1 for taking it out in stock form and seeing what it needs before digging too far into it. That said... If you've got the automatic transmission, consider adding an external cooler to help it out. Look up the Missing Link. I don't have an R50 to try it on, but I've read it firms up the unibody a bit. If you've got the open rear diff, you can swap in a limited slip. Hawairish did a great writeup on repacking the LSD for higher breakaway torque, and a table of donors and specs for the stock units (scroll down a little). Looks like early Xterra is your best bet if you want to drop one in without taking it all to bits. Just make sure your donor has the same gear ratio. That's listed on the data plate in the engine bay, look for HG43 or HG46. Other than that, I would check the strut towers and fuel filler for rust (hopefully low miles means it hasn't seen too much east coast road salt), and make sure it's up on its maintenance. At 78k, it may still have its original timing belt.

Halfway there! I don't remember what code it threw, if any, but IIRC my dad's '01 had a random intermittent misfire that the dealer said was probably a coil pack. They couldn't track down which one was the problem and wanted to do them all. A set of coil packs ain't cheap, so I would first look for any obvious vac leaks, gunk on the MAF, maybe check the color and condition of the spark plugs to see if you've got an overall mixture issue or an obvious single-cylinder fault (or a bunch of oil in the plug wells). Have a look at the coil packs while they're out, look for evidence of arcing. Do you feel the misfire under certain conditions?

Running the aircon does make more heat, but I don't know how much of that heat would get around the inner fenders. The panels on mine get hot this time of year because the sun is out (usually, right now we're smoked in) and the paint is black.

From what I've read it sounds like you can swap panels pre/post facelift, but only if you do the whole nose. And yeah, the QX4 should be mechanically the same. Maybe more likely to have the auto transfer case.

We have a dark theme?