Slartibartfast

Congrats on the milestone of working steering! Feels like this thing's getting close.

I think you're a tooth off between the cams. Should be 40 belt teeth between the cam sprocket dimples. I think I'm seeing 39. (Tough to tell, though--that lower right pic doesn't quite show the driver's side dimple.) Verify 43 belt teeth between the driver's side cam dimple and the crank dimple while you're at it. Don't worry if this puts the sprocket dimples a little off from the marks on the cover. Mine didn't quite line up either. The tooth count has the final say. I suspect a disagreement between the two led to that second white line drawn on the belt, and the belt being a tooth off, and the engine running poorly. I see the fasteners that hold the rear timing cover to the intake are missing. Do the holes for those not line up? The VG30 intake gaskets are much thicker than the stamped steel VG33 intake gaskets, so if you use the wrong ones, a lot of stuff doesn't line up properly, including those holes. I found this out the hard way on mine when Rockauto sold me the wrong parts. Mr. 510 also ran into this issue on his VG34 build, so even if it's going on a VG33, the VG30 intake still needs the VG30 gaskets.

+1 for checking the sunroof drains. I ran with no outer seal for quite a while and never got water inside.

For coolant to leave from the top of the rad, it would have to enter from the bottom of the rad. If the tstat is closed, the lower rad hose is blocked, so suction at the top of the rad would have no effect. Like you're sucking on a straw with the end blocked. If the tstat is open, the pump is sucking coolant through that bottom hose. So now there's someone else sucking on the other end of the straw, and they're better at it, and man that got weird fast. So there's either a deadhead or suction at the bottom of the rad, and an unrestricted supply of coolant coming out of the engine at the top. The datalog could be interesting, but leave the two-wire sensor alone and use the one-wire sensor for the dash (with the wire to the dash unplugged) instead. Two circuits trying to check resistance across one sensor could end badly, or at least give weird and unreliable data. And yeah, at this rate I'm gonna end up with a full backup of Nico's service manual collection on my hard drive. Sometimes it's worth it, though--last night I stumbled on the "body sonic system" in the '84 ZX manual. Looks like it had kickers in the seats, hooked to the radio. Butt subs. Oh, and RE convection. Some early cars and tractors did not have water pumps, and relied entirely on thermosiphon cooling. Heat rises in the block, cold falls in the radiator, coolant circulates. It even kinda works, mostly.

Hot coolant naturally rises over cold coolant. So even though there's no flow directly past the sensor when the tstat is closed, the warmer coolant will still make its way to the top of the system, which is why they put the temp sensor there. That sensor location is also why the heater core and intake warming circuits run back to the cold side. Both of those circuits are dumping heat, so the coolant coming out of them will be cooler than the actual engine temperature. If this cooler coolant was introduced to the system at the top, it would mix with the hot coolant around the sensor, giving the computer an inaccurate idea of how hot the engine was. Figuring out the rest of the coolant flow was more difficult than it had a right to be, mostly because flowcharts were a terrible way to try and explain this system, but also because Nissan doesn't seem to understand them either. Now that I'm really looking at them, the flowcharts in both the '95 and '87 manuals are just straight-up wrong. They show the water pump only being fed when the tstat is closed, and the tstat and rad forming a loop on their own, sans pump and engine, when the tstat is open. So, yeah, that ain't right. The Fronty flowchart makes a lot more sense. To confirm that it's the same as the VG30 cooling system, I pulled up yet another manual, this time for the '85 300ZX (which also had a SOHC VG30). That diagram looks very similar to the Fronty diagram, apart from the turbocharger of course. So, yeah, near as I can tell, that Fronty diagram should be correct for this application. It looks like the end of the thermostat is what blocks off the bypass hose. So as the thermostat opens, it's allowing more flow from the radiator, while throttling flow from the bypass hose. (Kinda like the hot/cold mixer knob in a shower.) This one-wax-motor-moves-two-valves thing would've been explained much better in a cutaway than it is in those stupid flowcharts! I did find a cutaway in the '93 300ZX manual, so check that out if you're struggling to visualize this--though that car has the DOHC VG, and I don't know what else changed on that variant, so don't trust it too far. Hopefully that explains it! I did not expect the rabbit hole to go that deep, or the rabbit at the bottom to be that vicious. I wonder if the borked flowcharts were drawn by the same guy who copy/pasted that fuel pressure test. (For those who don't know--the fuel pressure test in the WD21 service manual mentions a fuel pressure regulator control system, which was not fitted to these, but was present in some early 300ZXs.)

My bad, I was thinking in VG30! The pulleys on mine are bolted to the balancer. Looks like the VG33 combined the two so you can't mess it up. No idea why the marks are in the wrong place then, unless you've got the timing light on the wrong plug wire, or the rubber in the balancer has let go and allowed the pulley ring to slip. Good to hear the mileage is back up, at least! The noise could be a lot of things, and I don't know the R50 engine bay too well. Run it without the belts (briefly) to see if the noise goes away. If it does, check the bearings in the accessories and the idler pulley. Could be one of those singing the song of its people.

It is built like an electric choke, but no, it does not mess with the mixture. Just the idle speed. The IACV raises the idle by giving the air blocked by the throttle an alternate path into the manifold (bypassing the throttle). This has the same effect as opening the throttle slightly. In fact the VG33 does exactly that, using a wax element (like what's in a thermostat) to prevent the throttle from closing fully when it's cold. Warm idle also bypasses the throttle body, but is controlled by the computer. I don't know why the two systems are separate. None of this should change the air/fuel ratio. The air that the IACV (or the thermo element) is letting into the intake manifold still has to go through the MAF sensor, so the computer knows about it, and will maintain the mixture accordingly. (Also, sorry for the radio silence on your wiring question--will get back to that soon!)

It sounds like your poor truck has a big pile of comorbidities going on here. The pulley can bolt to the balancer six different ways. Sounds like the last guy put it on wrong. Fixing that will bring the marks around to where they should be. Make sure you set the timing with the engine warm. The IACV's entire job is to mess with the idle. If it's stuck wide open, or some muppet adjusted it wide open to try and mask another problem, that would make it idle high. A vacuum leak elsewhere could do the same. Adjusting the IACV would be my last resort unless I had reason to believe that it had already been messed with. I would run down the troubleshooting for the IACV code in the service manual. The manual should also have instructions for adjusting the IACV properly. Loud noises under the valve covers are concerning. I've heard of the cam retainer bolts coming loose and chewing stuff up. Something to check when you have the covers off, if not sooner. Might even be timing belt slap if the guy who left the water pump bolts loose was the same guy who installed the tensioner. And yeah, I'd be shopping for head gaskets--or possibly a used engine.

The different compression on each bank makes sense with how the timing was screwed up. Now that's fixed, I would check the ignition timing. If someone messed with that in an attempt to get it running better with the cam timing screwed up, it could be way off, which might explain both the overheating and the awful fuel economy. Oil in the overflow is not a good sign. Are you sure it's oil? The inside of mine's got some rusty crap in the bottom that isn't hurting anything. If it's on top, then, yeah, that ain't good. Best case someone put something stupid in there (either trying to clog a leak or just topping it up with something that wasn't coolant), worst case... I guess a head gasket could fail between the oil port for the top end and a cooling jacket, but I don't think I've heard of a VG doing that. Good that there's no exhaust in the coolant. Any butterscotch pudding under the oil cap? A while back I checked out an R51 with SMOD (ATF in the coolant). The gasket on the radiator cap had swelled so much that I had a hard time putting it back on. Yours doesn't seem to have done that. Did you use fresh coolant after replacing the pump? And did it look like this before? Make sure the cooling system is properly bled! There's a bolt for that on the upper intake. (If you didn't bleed that after doing the rad, the resulting air pocket may have something to do with your current overheating.)

LOL yeah, there are still plenty of reasons to question the engineers on these. The steering linkage, the strut rods, access to the #6 spark plug...

It is nice to have a few manuals to play off each other! The '87 in particular has lots of weird first-year stuff that's not in the later manuals, including a just-different-enough-to-cause-problems engine diagnostic code table. Nissan also put the tstat on the cold side of the KA and the VQ, and Chevy did something similar on the LS V8s, so clearly there was some kind of thinking behind it. I have not found anything that explains what that thinking was. My best guess is that mounting the tstat lower means it's not sitting in the hottest water in the engine, so it's opening later, helping the engine come up to operating temp quicker (which is better for fuel economy, engine wear, and of course emissions.) But that's just a guess. Whatever effect they were going for on the VG, I guess they decided there was some meat left on that bone when they drew up the VQ, because it's even weirder. They still put the tstat on the cold side, but they also split up the coolant outlets for the block and the heads, which let them put a second tstat on the hot side of just the block.

Nope! Other way around. Hot coolant passes from the engine to the rad via the upper hose, and cooled coolant returns via the lower. This is the direction in which the thermosiphon effect is pushing the coolant anyway, so it's how most cooling systems work. (There are reverse-flow oddballs out there, notably the GM LT1, but the VG is not on that list.) This means the VG's thermostat is on the cold side. I don't know why Nissan did this, but it seems to work. There's a flow chart (heh) on LC-6 of the '94 FSM, but this diagram from the '87 is a little easier to understand--at least once you work out that the grey arrows mean something different in the diagram than they do in the flow chart below.

CL-9 in the '95 manual shows the damper. Looking at the diagram, it's even simpler than I had assumed it was! I thought it was supposed to slow engagement if you pop the clutch, but it looks like it's just adding a little squish to the system. NVH thing? Probably unrelated to this issue, unless it's gone all to pieces inside and the debris was blocking the line back to the master. Now that I'm thinking about it, I've heard of rubber brake hoses failing like a check valve, so you can apply the brake, but it won't release. I haven't heard of a clutch hose doing that, but it sure does sound like what yours was doing. Ackshually the manual calls it an "Operating Cylinder," but, yeah, nobody else does. I've only ever seen/heard it called a slave cylinder.

New one on me. My first thought is heat soak (exhaust leak cooking the clutch hydraulics?) but I would expect that to prevent disengaging the clutch, not make it slip. Does yours still have the clutch damper? I've heard of those acting up. Haven't had to mess with one, given mine's got the slushbox.

A friend and I hole-sawed his S10 Blazer's firewall to get to a bellhousing bolt. Then we did it again, a few inches over, because that's where the bolt actually was. Not our finest moment. (Or Chevy's finest moment, either, but that's the S10 for you.) If you do go for the hole saw, make sure you measure better than we did. Also make sure the hole saw and/or pilot drill aren't going to take out the harness when they break through. I've got a trans with this sensor in the corner, waiting to go into my '93. I think I just found something else to check before I install it!

There are two temp sensors. The one for the dash is one-wire. The one for the computer has two. If the plug for the two-wire is damaged, that could well explain why it's running rich. If it's not the sensor, and it really is struggling to come up to temp, that suggests a stuck or missing thermostat, which could also explain it running rich. If you're looking for the plug for the one-wire, I would try a few sizes of spade terminal and see which one fits. I suspect the stock plug is just a spade terminal with a fancy plastic case on it.

Not immediately ringing bells, but I'll have a poke at the manual. What are the wire colors for that plug? Should help narrow it down.

Sounds like the last guy had no idea what he was doing! Lucky the valves didn't get et. You'd need the spark timing to be pretty far off to get misfire codes, but you could still be losing performance if it's off. Spec is 15 degrees BTDC plus or minus 2, at warm idle. (If you set it cold, it'll be off once it warms up.)

These aren't great on gas, but it should be getting better than 11.5 on the highway. I would check the timing (instructions are in the service manual, free download from nicoclub) and see if it's got any stored codes. Check/clean the MAF, check for vacuum leaks. Maybe throw some injector cleaner in the tank on the off chance it does something. Good thinking doing the timing belt right off. I did the same when I got mine. I also changed the fluid in the transfer case and the transmission, and added an aux cooler and external filter to the trans cooler lines in hopes of keeping the slushbox alive (so far so good). Who knows what maintenance a $300 truck has/hasn't seen over the years. I haven't heard much about the K&N filters that makes me want one. If you do get one, be careful with how much you oil it. I've heard of the oil fouling MAF sensors.

I remember someone ages ago punched a couple of holes in a Nalgene bottle and ran that for a washer res. Might be below the standards of this build, though I knew shocks could get complicated, didn't know the springs did too! I would not have expected the order of the springs to matter.

Trailmaster used to make a 4" kit that dropped the whole front suspension down, like a subframe drop for a unibody truck, but that's long since out of production. Otherwise, no, you're not gonna get more than 3" out of the IFS. Body lifts are still available, though. I remember a few people here running 3+3 and 33s (3" suspension, 3" body, 33" tires) back when I joined. Beyond that, yeah, you're looking at hardcore custom fab.

Looks like the OE part number is 472101W700. If you can find the original listing, it may list what it fits.

Is yours round-dash or square-dash? If it's square, get the '90 manual off cardiagn.com. Round, use the '94/'95 from Nico.

Here's a guide to manual-swapping a '96-'99 truck. (Not mine, all credit goes to Keith Maddox.) Not sure if the guide talks about the oil or not, but in case it doesn't, you want GL-4, not GL-5. AFAIK the VG33-powered R50 got the same manual trans as the VG33 W/D22 (first-gen Frontier and Xterra). The W/D21 trans should also work, but Nissan did a dumb with the oil level in the early ones, so if you have the option, I'd look for a '96+ donor. VQ35/manual R50s do exist, but as Hawairish said, they are quite rare. Good luck finding parts. There was a guy on here a while back having a hell of a time finding a flywheel for one. Either way, I would look for a manual R50 with the same engine and something wrong with it. Part yours out to fix it, or part it out to swap yours. Saves you finding all the pieces separately.

Sadly Nissan did not put a Shrader valve on the rail. The service manual says to plumb a pressure gauge in between the filter and the rail. You want around 34 psi with the engine idling and the vacuum line to the regulator hooked up, and around 43 with the vac line off. (If there's fuel in that vacuum line, then the regulator's toast.) You'll spray fuel from hell to breakfast if you open the lines while they're pressurized. The manual says to pull the fuel pump fuse, start the engine, wait for it to die, and then crank it a few more times to be sure. This may be difficult given how yours doesn't really run. Worst case, let it sit overnight to hopefully bleed the pressure down, and then separate the lines with a rag wrapped around the bit you're separating in case it's still pressurized. Both procedures and specs are on EC-37 of the 2000 service manual, free download from Nicoclub. I'm guessing the truck sat for a bit after the belt failed, given the dead fuel pump. How bad did the old fuel smell? Hopefully it hasn't gummed something else up. I would be surprised if the fuel filter was bad enough to cause a no-start, but I would still throw one of those at it while I was in there. Pull a spark plug after it runs/dies. If it's wet, then you know it's getting fuel. If it's getting fuel, my next guess is timing. Did you mess with the distributor? Do you know that the last guy didn't? I would try adjusting the timing around and see if that changed anything. (If you don't think it's been messed with, mark it first so you can put it back where it was if you don't get anywhere.) If the distributor has been out, it could also be a tooth off. I doubt the knock sensor code is related.