Slartibartfast

There's a bleed screw on the intake for getting rid of air trapped in the cooling system. Bubbles in the coolant shouldn't change the speed of the blower. The fan runs off a brushed DC motor, and when brushes wear out, motors do strange things. Dry or worn bushings can cause issues as well. Probably easiest to just swap it for your spare and see if the issue goes away. I'm not sure what to make of vehicle acceleration changing the blower speed. Do the headlights or dash lights fluctuate at the same time? If you suspect the alternator is flaking out, check across the battery with a voltmeter to see if the voltage is doing weird things.

From what I've heard of iffy lube, the first thing I'd do is make sure they did actually put oil back in it. Check the vacuum lines, they're in the same general vicinity as the dipstick so they could've gotten bumped. You can also check the connectors in that area, particularly the wiring to the MAF sensor, for looseness and/or corrosion.

I've never even heard of one of these being fitted with a power sunroof. The manual sunroofs have drains in the channel between the roof and the seal on either side (towards the front IIRC).

Having used the $1300 equipment once, I'm not sure it does LOL. That thing was amazing. Quieter, too. Here's my hackjob: I've seen a few better designs since I made it. One guy used a bunch of incense sticks in a can, which probably smelled better. Another guy used a hot resistor in a pot of baby oil. Come to think of it, the pro machine I used ran baby oil and was probably just that, only painted up nice and with wheels on it. Probably wouldn't be difficult to replicate, now that I'm thinking about it.

The valves themselves pass exhaust gas, so I don't imagine they're full of plastic parts that are picky about solvents, assuming you're not spraying into the vac fittings. Carb cleaner would probably be my first choice. Again, I'd be more worried about the solvent I dumped in draining into the intake manifold, especially if I suspected that the valve was sticking open. As for cleaning the outside, I'd just take a wire brush to it. I don't think my '95 had one of those little beads in the line. Seems like a difficult thing to install by mistake, so I would guess at it being some sort of damper or something. Check the service manual! You might also check the vacuum routing diagram on the underside of the hood to see if it shows anything there.

I tried cleaning and greasing one of mine on my '95 when it started to act up (sticking mostly), and found the clutches inside were worn way past the acceptable spec in the manual. I put it back together anyway and found that I'd made the problem worse by removing the thick gunk. At one point, the hub either tried to engage or tried to disengage (no idea which, I never knew what those hubs were up to) while I was driving and ground loud enough that I pulled over to make sure the wheel wasn't about to fall off. I bought manuals soon after. Nobody seems to buy auto hubs in the part outs. You could probably find a cheap set of good used hubs to hold you over until you upgrade. I have two sets on my shelf, but one set is shot (see above) and I didn't test the other set before removing them from my '93.

I honestly have no idea. I would start with the service manual rather than a more generic list that looks to be geared more towards GM products anyway. Pre-round dash WD21s didn't have a BPT valve. This was added (and apparently carried over to the R50) to shut the main EGR valve when exhaust backpressure rose (basically turning off the EGR when the engine is loaded). That doesn't sound like it would change idle, but for some reason it did when you unhooked it. Having looked at the manual again, I would be more inclined to suspect the EGRC solenoid valve (which lets the computer shut down the EGR at idle or high revs), but that doesn't explain why unhooking the BPT would change anything. Then again, I'm looking at the '95 manual, and Nissan may well have changed the operation of the 3.3's EGR. Again, download the appropriate year of the service manual, find the EF&EC section, and look up how the EGR is supposed to work. Somewhere in there you should find descriptions of the parts, their location, and how they're hooked together. If you're running the original vac lines, probably best to replace those, they do dry out over time and new line is cheap. Poke around, take stuff apart, try to rule things out, eventually you'll either stumble onto the issue (like I did with the rotted hose) or rule everything else out.

Interesting that the BPT seems to be acting up. I remember the one on my '95 had a short rubber hose at the bottom (where exhaust pressure joins up) that was dry-rotted and had a big hole in the back. It looked fine until I removed the valve and could see the back. I would start by checking that. IIRC the service manual has procedures to test the valves manually, most likely in the EF&EC section. ... so that's what BPT stands for. Thanks for clearing that up!

Hard to know how long it'll hold without seeing it in person. Hard to know if my armchair diagnosis holds water, either. It could even be that the vacuum booster makes that noise normally, though having it come and go does sound suspicious. Depending on how the system failed, you could get weak brakes, a bad vacuum leak, or both. If it still idles fine when your foot's on the brake, and still stops, I wouldn't expect catastrophic failure, but I'd still look into it. From your observation that it comes and goes, I would start with the check valve between the intake and the booster. Easy to get at on a WD21, not sure how easy on an R50, probably not too bad though. IIRC it's just a one way valve, so it should let air through if blown from one side but not the other. If it lets a air through the wrong way, or it's gotten gummed up somehow, clean or replace and see if that makes a difference. Also inspect the hoses it hooks to for cracks, loose fittings, etc. Maybe have someone push the brakes and see if you can hear the hiss from the engine bay. Anyone with an R50 got a better idea what's going on here?

Good to hear swapping tires sorted most of it. Do you have one of those bolt-in panhard drops? Might check the bolts and make sure the back end's not shifting on that.

You could drill a hole, or you could just get a T-fitting and make two vac lines into one. BTW, the ports on the intake pipe aren't vacuum, you only run into vacuum after the TB. The lines on the intake are where the carbon can discharges and IIRC where the vacuum actuators suck air from to disengage. Also, if your intake keeps ripping, you might want to check your motor mounts.

Mine clicks when I put my foot on the brake in park too, that's just the shift lock disengaging. It's kind of a safety interlock to keep you from bumping it into gear by accident, or to prevent a kid left in the car from playing with the controls. The hissing sounds like there's a leak in the vacuum pipe between the intake and the brake booster, or a failing booster. If you shut the engine off and step on the brake, does the pedal go hard immediately, or does it take a few pumps?

I saw a video on Youtube where the guy hooked a cheap 12v air compressor to a glass jar with a burning charcoal briquette and some torn-up cardboard inside. It seemed to work pretty well, but I was a little leery of shooting bits of cardboard into the motor, so I designed a similar unit around a cigarette. It works great, except that each cigarette only lasts about a minute. I had no idea how expensive those things are. I'll bet something based on the glycerine/water mix in a fog machine or a vape pen would work pretty well.

I found some thick black goopy crap in the top rings on mine. Removing that seemed to help somewhat. I've also heard of spray silicone helping, haven't tried that yet though.

Huh. A friend of mine has two 4.3s in his driveway (Astro and Blazer) and they've actually been pretty good. Both are '98, so maybe late enough that Chevy had worked some of the electrical bugs out. The balance shaft arrangement is kind of a weird compromise, and the fuel spider's kinda hokey, but most of the issues he's had were from the POs running them into the ground. They're fairly simple to work on when there isn't a van wrapped around them. They might not be my first choice if I was going to all the trouble of an engine swap, but you could do a lot worse. There's also no timing belt to go wrong... that has to count for something.

Damn. But yeah, could've been much worse.

2000 model is a VG33, which is interference. It's less interference than the VG30, and I have heard of people getting lucky, but it does the ability to knacker itself. You could just throw a belt on it and see if you can hear any dead spots while cranking. Autozone may be confused because there were non-interference 3.3s made... for use in a rebadged Quest van sold by Ford. If the valves are in fact shot, you could just swap out the heads. At 340k, though, it might make more sense to find a lower-miles motor to start with.

The motor in my friend's Blazer jumped a whole lot more than that with broken mounts.

You can check the ignition by removing the clamshell and testing from the solder point on the back (with the black and yellow wire) to ground. The tach going out at the same time is interesting but hopefully unrelated.

It's a bit of a pain but I've done worse. I helped a friend change a belt on a quad-cam Kia once. Lining up two camshafts in a Pathy is pretty easy compared to lining up four, two of which will try to move as soon as the belt comes off. I ended up making a tool with a couple nubs on the end of a rod to grab cam sprockets. It holds the sprocket in place for removing or retorqueing the bolt that holds it on and makes lining it up to the belt easy too. If you got really lucky and the valves are fine, make sure you replace all the stuff you can't get to without pulling the belt off again. I skipped the crank seal the first time I did my belt and got to take it all apart again.

Really depends on how bad the exhaust inlet fitting is. If that's seized, you're gonna have a hell of a time. If not, there really isn't much else holding it down, just a couple bolts to the intake and some vac lines. The one on my '93 was really easy thanks to some PO or mechanic who'd smeared gobs of antiseize on the connection to the pipe going down to the manifold. The one on my '95 was rusted solid, and either stripped when I tried to undo it or was already stripped and the last guy had just sort of jammed it back into place for me to find. That one was bad enough that I had to replace the valve and cut 3/8" or so off the end of the coupler sleeve bit to get down to threads with any hope of grabbing the new (salvage) valve. If yours fights you, try it hot, try penetrating oil, try sacrificing a goat...

Thanks! I'm happy to have it fixed, I was worried there was something screwy in the wiring, and I'm tired of taking this dashboard out! The LED's not bright enough to be distracting, but it is a little brighter than it needs to be. I might try adding some kind of diffuser if I open it up again. I did try the blue condom off the stock bulb, but that just made the light blue (go figure), which wasn't really what I was after. I'll have to experiment when I do the bulbs in the other switches. Maybe the warm white LEDs would be a little softer. Here's some of the gunge that was on the circuit board. Given the other disgusting crap I found in this rig, I suspect it's largely cigarette derived. There was enough greasy crap between it and the board that I doubt it was shorting anything... still nice to know it's gone. I didn't take a picture after installing the resistor, but I ended up just cutting one of the circuit board traces on the far right (that went to the incandescent) and soldering the resistor there.

Not really. The only port you'd be able to get to without removing the connection to the manifold (which I'm assuming is seized if you want to try cleaning w/o removing) is the one inside the intake, and IIRC you can only find that one by braille with the throttle body off. Besides, if there are chunks of carbon in the valve, it's probably best to avoid dropping them down the intake.

There are a few engine grounds under the hood. A couple of them go to the exhaust manifold heat shields. That should be connected.

The RR mounts: click I tried to talk a friend into welding chains to the broken mounts on his Blazer, but apparently that was too redneck for him, so we ended up cutting the factory rubber and crap off the mounting plates and welding up mounts for some cylindrical rubber bushings he found online. It was a pain in the ass to make them fit right but the finished product works just fine, and even with the 4.3 it doesn't seem to put a lot of vibration into the frame. +1 on not using solid mounts, a mechanic I know tried solid mounts on his Yota and he said it just about rattled his teeth out.