Slartibartfast

And an amusing contrast.

Check out EL-76 in the '95 service manual. Every (stock) relay labelled on a diagram.

^^Agreed that codes are a good place to start. There's a writeup on here for checking the ECU. Basically you've got the ECU under the passenger's seat, which you can get to by sliding the seat forward and laying on the floor, or you can just pull the seat (four bolts and a plug if you have butt toasters). Then there's a slotted shaft labelled "idle adjust" for some reason. It doesn't adjust anything. Been a while since I did it from the computer but IIRC you go full counter clockwise, then full clockwise (key on, not running) and the two lights should flash together. One flash, two flashes, three flashes. At three flashes, turn it full counter clockwise again, and it'll spit up codes, red for the 10s digit and green for the 1s. The writeup's got the code list. Those are the only temp sensors (one for the computer, one for the gauge) but there are lots of other sensors that can cause issues. Backfiring is unusual. I'd check the vac lines, especially the one to the pressure regulator on the back of the engine, but that's probably not it. Temp gauge may be a problem with the cluster--I've heard some guys get away with just tightening up the screws on the circuit board, others replace a voltage regulator on the back, but I think the ones with bad regulators lose the fuel (?) gauge too. The temp gauge in my '93 only came up a little when I got it. I swapped out a few things all around the same time (temp sensor, thermostat, and lots of unrelated stuff) and cleaned up the temp sensor connectors and the gauge works just fine now, which is nice, but of course I don't know which thing fixed the problem.

^ There is a lot to be said for making things easier on yourself, especially if you haven't done the job before. Just make sure it's well-supported before you're on your back yanking on stuff.

I just walked out to my truck, set the key to the run position, and jumpered between white/red (battery +) and black/yellow (easy because the plastic clamshell is broken). Hotwiring it like that made it crank. It did not start, however. Perhaps both the black/yellow and the black/green must be connected to + for the engine to start, so that a tweaker trying to hotwire your car will just sit there running the starter until the battery drains. In any case, if black/yellow was a ground, the bread tie I was using as a jumper would've burned up, or the fuse links would've popped, and either way the engine would not have turned over. There is also no reason why the ignition switch would need a ground wire. It's just a switch on the + line. Connecting the + line straight to ground would just fry the fuse links. There's no antitheft chip-key bollocks in the lock cylinder that would require a ground. So, why are you seeing voltage from white/red to black/yellow? Your test light is finding ground through the starter solenoid. A test light doesn't require much amperage to light up, so as far as it cares, the starter solenoid is just a wire between it and ground. The circuit goes dead when you're not in park or neutral because the inhibitor relay (which is between the ignition and the solenoid) breaks the circuit to prevent you from starting in gear. A test light will not tell you if it's getting a proper ground or if it's grounding through a load (a relay, light, solenoid, actuator, whatever). (battery +) ------ (fuse links) ---white/red--- (switch) ---green/black--- (inhibitor) ------ (solenoid) ----- (ground) That's the circuit. Fuse links are just wire, assuming they're not blown, so ignore them. The solenoid is just a coil of wire, and at the very small amperage it takes to light up the bulb in your tester, its resistance is negligible. Current goes straight through. Let's assume your inhibitor is not inhibiting. Mark that off too. Now you've got this: (battery +) ----- (switch) ------ (ground) Obviously that's not how the circuit is, but it's how it looks to the test light. If you test across any switch that's turned off, unless the load has a higher resistance than the little bulb in your test light or the circuitry in your voltmeter, you should see battery voltage or something close to it. (Turn the switch on with the tester across it and the meter should read zero or the test light should go out.) It's not hard to misinterpret an electrical tester. A weak ground can also look perfectly good to a tester, but fail under load. Being an idiot helps too--I once unwrapped part of my wiring harness looking for a short circuit in my passenger's side high beam. It had me confused because it wasn't a dead short, but it was clearly leaking to ground somewhere. That somewhere turned out to be the little bulb in the cluster that tells me the high beams are on. In any case, I'm pretty sure the starter circuit is not what was causing your issue. Yes, it wouldn't crank; but I'm guessing the inhibitor relay gets its power (through the switch in the shifter of course) from the RUN circuit, so if RUN is interrupted, the inhibitor inhibits and the starter doesn't work. The systems that still worked when you lost power are systems that don't receive power through the ignition switch. I would be less suspicious of the switch at this point and more of the run of wire and the fuse links through which it draws power--though of course the engine swap and security system may complicate matters.

I think I've got that same manual around here somewhere. The one with the old Datsun pickup on the front? Download the FSM, it's way better. The alty's kind of a PITA but $350 does seem a little out there. The alt pivots at the top and the adjuster is underneath. (Behind the skidplate, if you haven't pulled that yet.) Looking at mine, you should be able to see the fasteners from above, at least well enough to get an idea of what you're up against. Pull it from underneath. I don't remember for sure but I think I may have unbolted the tensioner bracket from the motor to get that out of my way--been a while though. I don't think I pulled the wheel, though cranking the steering hard to the driver's side might give you a little extra clearance, or a place to put a light. Make sure you get the wires off before the alt is hanging from them. If you want an upgrade, the alt from a SOHC Maxima is supposed to bolt right up if you swap the pulley off your old one. 90a vs the stock 70a.

IIRC these transfers were originally filled with whatever was in the transmission--so oil if bolted to a manual, ATF if on a slushbox. They're not real complicated so they're not real picky. Maybe the matching fluid spec was so a bad seal in between can't mix oil and ATF, though I haven't heard of anyone having that issue on a Pathfinder. It could just be a convenience thing. Both my '95 and '93 (both slushbox) had ATF in the transfer cases, and when I drained them, I refilled with the same. My friend's S10 Blazer uses ATF in the transfer as well. This was a good thing when the one seal separating the his transfer case from the 4L60E decided it had seen enough and allowed the transmission to overfill the transfer case. I've read that the Nissan setup is better designed but I haven't stared at the manual or cracked one open to check.

Yep, front diff is above the skid plate. Should be easy enough to get the plate off, though the little 10mm head bolts that hold it on shear off more easily than they should. Must be made of the same junk as the exhaust studs. I don't remember the indicators for which diff you have (outside of general rules for the US market) but if you can get a few pictures of what you're looking at, someone will probably recognize it. Or look around, I remember a thread recently trying to ID an axle.

^ Debris is my guess as well, and I'm not aware of any heater valves. I had another look at the manual and it looks like that passenger's side hose that's blocked is the return. It goes down a long pipe under the intake to the thermostat housing, so hopefully you'll find whatever the problem is when you're replacing the thermostat. If you don't find a lump of something in the thermostat housing, you may have enough access to run a wire or something into that pipe to try and poke out whatever might be in there (assuming the clog is between the heater hose and the thermostat). Here's the diagram from the service manual, for what it's worth.

Not DOT rated, so not legal for use on public roads in the US. Also I doubt there's any kind of cutoff for the low beam, so, yes, likely blinding. I've seen conversion housings you can get that run the H4 halogen bulbs in that same style of lens. DOT rated, just about bolt-on if you pick up a Hardbody grille and buckets. I've read good things about them. You can also get proper DOT rated LED headlights in the same sealed-beam size but they're ludicrously expensive and IMO ugly as hell. For the lightbar, when I wired my driving lights, I used the high beam lead from the headlight switch as the + source for the switch. That way the driving lights only work when the high beams are on. Switch to low beam because there's a car in the other lane and the driving lights go off as well. Saves you having to work two switches at once to avoid blinding people.

On my '93, and in the '89 manual, black/yellow at the ignition switch should be battery + when the key is in the start position. Not ground. The alarm under the seat in my '93 has the multi connector at one side, then a smaller plug with two black/yellow wires that actually have "Starter" printed on them plugged into another side. Unplug the starter wires from the alarm and, surprise, it won't crank. Jumper those two black/yellow wires together with a paper clip and it starts right up. (Sounds like you may have a different alarm unit.) Looks like another black/yellow wire goes to the ECU, though I'm guessing that one dead-ends on yours after the V8 swap. I haven't looked up the whole schematic but I suspect the wire you tested from the interlock had the other end hooked to the starter solenoid, which has its other end hooked to ground. If the shift interlock is closed, the wiring coming off it would test as ground. I doubt the clutch switch is the problem, though I think I'd rig up a jumper on the electrical plug rather than just tying the pedal down.

The O2 sensor on one of these is three-wire, and if you have small hands or don't mind pulling the passenger's seat, you can check its operation from the ECU. Or, like with the MAF, you can just unplug it and see if the engine runs better guessing at its mixture than it did listening to the sensor.

Can't say I blew into that hose when I had mine apart, but fully blocked off doesn't sound right. Looking at the cooling circuit in the '89 manual, I'm not seeing anything that should be blocking it. Looks like to get to the heater, coolant has to flow from the head to the manifold, where it branches, then to the heater core, then back to the thermostat housing. If I had to guess I'd say the passage in the intake might be blocked up (though I can't see which hose is which from the diagram).

Between 0.7 and 2.2 lb/f according to page EM-20 of the '95 service manual. Hand tight with a screwdriver worked great for mine.

There's a switch in the throttle position sensor that tells the computer when it needs to control the idle. I'm not familiar with the setup on the TBI rigs but that's where I'd start. My '95 acted up like that occasionally, fine when my foot was down but stalling at stop signs otherwise, and screwing with the TPS wiring (among other things) seemed to clear it up. I never did quite track it down, mostly because it would vanish each time I tried!

Sounds like a bad O2 to me. If you want to be sure, though, there's a test procedure in the service manual for the O2 sensor. EF&EC section, looks like it starts around page 36. Like checking codes except you want mode 1, not mode 3. The O2 can only tell the computer "Rich" or "Lean," so when it's running closed loop, the computer adjusts the fuel mix to bounce back and forth between the two. In mode 1, the green LED flashes with the O2 sensor reading. If the light remains on or off when the truck should be running closed loop, the sensor is probably shot. If the computer knows the O2 is bad (or unplugged) it'll just throw a code and run on open loop all the time. Sounds like that's what it did all winter. The trouble is when the sensor is wrong but the computer doesn't know it. The sensor fails showing lean, the computer adds fuel to try and change lean to rich, and when the sensor still reads lean, the computer just keeps adding fuel, so the engine runs like crap. Because the issue is intermittent, you might try checking the wiring between the plug and the sensor before condemning the sensor, on the off chance something is wrong there (which might explain why the issue is intermittent). The guy who fixed the exhaust on my '95 cut the O2 wires and spliced them back with some kinda hokey connector that didn't hold on for long. If/when you do end up replacing the O2, I've read that it's easiest to do with the exhaust hot. I haven't tried that, but it sure was a PITA when I did it with the exhaust cold, so the next one I do I'm warming up first!

Yes. Whatever the temperature, the ECU needs to know the speed and position of the camshaft (using the position sensor in the distributor) so it knows when to apply fuel and spark. It needs the MAF to tell it how much air is going in and the temp sensor to tell it the motor's temperature so it knows how much fuel to inject. If the ECU can tell the MAF or temp sensor isn't working, it guesses at what the values probably should be well enough to limp you home. The computer's not great at knowing when a sensor is shot, though. If the MAF or temp sensor is malfunctioning, but the ECU doesn't know it, your fuel mix gets thrown off. A common test on the MAF is to unplug it and see if the engine runs better on guesswork; if it does, there's something wrong with the sensor. I would try the same test on the coolant temp sensor. Re-reading your symptoms (more closely this time!) it kinda sounds like it's flooding out, and I've heard of these doing that when the temp sensor or temp sensor connections are shot.

Beat on the console a little more and mounted up some cheap silicone wiper blades. I've heard good things about them... let's see if they hold up to winter.

Sorry I missed that! Rules that out then.

If you want to check your gas for water or see how the inside of the tank is doing, the pump's under an access cover under the cargo area carpet, so you don't have to drop the tank to take a look. I would be very surprised if two-year old gas was the problem, though. And vacuum in the tank, you mean that hiss when you open the cap? Both of mine have done that whether they had an issue or not--I think it's just how the evap system works. The bad dizzy on these usually crops up as the engine warms up (from what I've read, anyway, haven't had a problem with mine yet). Runs fine, warms up, then has issues. Sounds like yours won't do anything but idle, if that, then conks out entirely once warm, so I'm not sure the dizzy is what's wrong. In the first post, you mention the catalyst getting hot enough to glow, possibly due to a misfire. That makes me wonder if the cat might have overheated enough to melt the catalyst honeycomb stuff and clog up. This makes sense with it's stalling out when you give it gas, but running--somewhat--at idle. The PO of mine had a guy drill a hole in the exhaust and stick a camera in there to check that the cat was good. If the dizzy doesn't fix the problem, you might try something similar. Funny story, actually, the PO of mine had the cat checked, injectors cleaned, all kinds of stuff to try and chase down the lack of power, and nobody thought to check the airbox. Turns out there was a rat's nest in there. And a rat. Hopefully the issue with yours ends up being as simple to fix, but better smelling. Oh, one last thing. Any ECU codes?

My dad had a naturally aspirated first-gen Xterra when I was a kid. It wasn't that comfortable (don't remember if it was the ride or just the seats) and it struggled to pull our small camper trailer.

Again I haven't had an R50 to bits. On a WD21, you remove a line of plastic screws (very carefully, they strip if you look at them wrong) from the tread plates at the bottom of the door openings, then lift the plates off, and that releases the edge of the carpet. Then under the carpet there's a white plastic cover, and under that you've got the wiring harness.

I've heard of the drive-by-wire throwing a fit when the throttle body is cleaned--cleaning changes the airflow enough that the computer assumes something is horribly wrong. There's a reset procedure here that might do the trick. Also discussion of it here (though on an R51). Unhooking the battery for 24 hours apparently resets it, but then you have to go through the relearn procedures anyway. Sounds like some guys have no luck calming the drama queen themselves and have to get it reset at the dealer.

Yeah, a fault in the wiring going to this smart access whatsit seems most likely to me. Taking a door off tends to be a pain, so I'd avoid that for now and go for the pillar trim. I haven't messed with an R50 much but if it's like a WD21, take the seat out first, it'll give you loads of extra room to work. If you find the plug for that rear door inside the B pillar, you might try unhooking that and seeing if pressing the door still makes the dome light kick on. If there's no change, you can rule out the door; if it changes the problem, then you may have tracked the issue down to something inside the door.

So, let me get this straight. Your door switches for the rear doors are removed, but you open the rear door and put a little force on it and the dome light comes on--but not the door ajar light. My first thought is that the door switches (on my WD21 anyway) ground straight to the body. There's one wire coming off of them, and it goes to the dome light. So if that wire is worn through, and it's hanging near bare metal, then it could be hitting that metal when you accelerate, or perhaps when you flex the B pillar ever so slightly. I'd be inclined to tear into the B pillar and see if there's anything obviously wrong in there. How's the hinge for that door? Can you see any deflection in the pillar? WD21s have a common dome light issue but it's usually the sensor for the rear hatch, which is built (poorly) into the latch itself. Hopefully they redesigned that for the R50, and it doesn't sound like it's your trouble spot anyway.