powderfinger

Good eye Mike, I'll take a closer look at that probably this weekend. I also plan to do another compression check and compare the results to my 2wd that I know has a strong engine since the last readings were low on the 4x4. Hopefully my gauge is just off but based off how the engine feels I doubt it is that far off.

I took at look and didn't see a temp sensor but in all honesty I didn't really look that hard yet. I did find a couple of possible issues though. The first is some sort of sensor on the throttle body that has the wires cut. Pic below, not sure what these wires went to, I haven't found two wires anywhere else that are cut. You can see the sensor on the left has two black wires, I believe one has a white or silver stripe and the other a yellow stripe and they have been cut. Highly doubt this is the temp sensor because of the location. The other thing I found is a connector with a wire missing. This connect comes right off the battery. I'll have to find a service manual for the Z24i so I can track these down.

Thanks, I'll look for the temp sensor. I know all the transmission bolts are tight because I just put the transmission in but I did not check the transfer case yet.

Just put a different transmission in it and it is still making the same noise but I guess it could also be the transfer case. Probably going to be trial and error until I figure it out. The noise sounds like its farther back near the rear diff but sometimes these things are hard to pin point. I am sure that will be easy to find 🙂 I'll start looking online this evening when I get home.

More true words have never been spoken. The previous owner of my 86 720 wanted to advance the timing farther that he could by simply turning the distributor so he nealry destroyed it by cutting the slot in the distributor all the way out the side so he could keep rotating it, (Z24i distributor adjustment is a little different that standard Z24 distributor). A pic would do it better justice but I don't have one. Timing was set to 30deg BTDC at least.

You'll probably have better luck posting this in the 720 section.

You can simply paste pictures directly into your post now as well. If you have any sort of image capturing program on your computer that allows you to draw a box around any thing on the screen and save it as an image you can do that and paste it into your post. I use Windows and there is a program already installed on most machines called "Snipping Tool" that works great. Any pic from any website I can just simply tell the program to capture and whatever I draw a box around around gets put in my temporary memory for me to paste where ever I want.

I haven't had it drop back to 1000RPM while driving yet but it will do it fairly consistently when sitting still. That being said I haven't driven it that much yet because I still haven't changed the front and rear diff fluid or the t-case fluid. I wasn't able to get the fill plug out of the t-case because the converter was in the way to get anything to it. Will probably just end up cutting the converter off because the bolts are rusted and rounded. This is the Z24i with the throttle body injection. I bought a service manual for 86 720 but I guess they decided to put the Z24i in the ST models after they printed the service manual because all it mentions is the standard carbureted engines, at least from what I have found so far. Truck also has some slack in the driveline, you can hear a pop after letting the clutch out sometimes when accelerating. Acts like a bad universal joint but I looked at them all and they seem good. The rear ones look fairly new. Worried it's the rear diff but I'll change u-joints first or just put an driveshaft from another truck on and try it out. I just realized I didn't attach a picture to the previous post like I meant to so here goes. It's is going to look really nice once I get the buffer out and wax it. It has rust bubbles over both rear wheels where mud sat on the inside lip of the wheel well for years and slowly ate away at the metal.

Got the transmission changed out this weekend, got everything back together, and put some tires on it. I got these wheels off of another 4x4 720 that I have, I almost used the factory 720 ST wheel but I am glad I went with these I think they look awesome. The other truck also has a brush guard on it that I plan to clean up and put on this truck. They are getting harder and harder to find, now I just need to find a roll bar that's made for these trucks. The truck still isn't running great, pretty sure I will end up pulling the motor sooner rather than later. The previous owner had the timing advanced past the 20deg mark. I got that straightened out but it still isn't running the best. It idles fine and once I get it up over 3000 RPMs it does ok but in between it really struggles. Even at idle I can press the gas to get it to rev up to 2000RPM and if I hold the gas there the truck will stumble and idle back down to 1000RPM before slowly climbing back to 2000RPM..strange.

Thanks Mike, sounds like I'll probably be sticking with the Z24i. I was hoping to just swap the other motor and keep it as is. It runs great with the Weber carb and I like the simplicity of the setup. All the emissions stuff has been taken off the engine in the 2wd as well. That's neither a good nor a bad thing but I will have to decide weather to swap all of that over from the Z24i engine in the 4x4. I am guessing some of it may be necessary for that setup?

I am thinking about swapping the motor from my 2wd into my 4wd so I can start daily driving the 4wd. Plus the transmission has to come out of the 4wd anyway. The 4wd motor runs decent-ish but has a nasty rattle to it. If I swap them, I can get the 2wd back together later. My question is, the 4wd has the Z24i in it, is there anything that will cause me problems putting my standard Z24 in a truck that has the "electro injection" engine in it? I would swap all the ignition components over with the motor out of the 2wd and it has a Weber carb on it so I think all I will need is one wire for that if I remember correctly. I know that the wiring is different for the Z24i but would there be any issue with ECU? Any other potential issues? Still not 100% sure I will do this yet but it seems like the quickest way to reliably get this truck on the road. I'll try to get a video posted sometime this week so everyone can hear the engine in the 4wd and give your diagnosis.

Yes, I meant the 235/75s would be around 5% higher than the 215/75s.

That's good to know that the earlier diffs are lower ratio. I'll keep my eye out, sometimes you see people selling whole trucks for little or nothing just to get them out of their yard. I am going to have to buy tires anyway because I don't want to run these loud ass mud tires all year. I'll do some digging to figure out what to get. Walmart has a great deal on some Goodyear Wranglers all terrains in 235/75/15 but that's the smallest they have, $80 each. Drop down to 215/75 or 225/75 and they don't even have any knock off chinese tires that cheap in an all terrain. Just nervous that the 5% higher ratio from the 215/75/15s will annoy me.

Man 215/75/15s will look mighty small on this truck but it's seems clear these 30.5s are way too big. I will definitely clean the calipers up this weekend and make sure the pads are moving fine, added to my list of other things to do before putting the truck on the road. Hopefully I'll have the transmission swapped out this weekend.

I also noticed when I changed the drivers side wheel bearing that when I put the caliper back on the inside brake pad was dragging on the rotor quite a bit causing a lot of resistance to turning the wheel. I know the lines have air in them because I have to pump the brakes at least once before they feel normal so that is something else that could be causing a major impact to acceleration.

Question for everyone here who has plenty of experience driving 4x4 720 trucks. I recently purchased another 720 that runs and drives but needs the transmission repaired and I believe the motor might be a little tired to say the least. How much of a power difference have you noticed with a taller tire? The truck currently has 30.5x9.5x15 tires on it and it came stock with 235/75/15. The 30.5s are about 1.5 inches taller than the stock tires and I believe these particular tires run on the tall end of that size spectrum as well. They are also mud tires and are pretty heavy. Just curious how much that could be playing into the lack of power this truck has. My 2wd will run circles around this truck but it has a fairly fresh motor in it with a Weber carb. This truck feels decent in 1st and 2nd gear because they are so low but as soon as I shift into 3rd on any kind of incline acceleration is barely there. The truck still has the original catalytic converter on it as well so not sure if that could be a little clogged. Haven't checked yet. I did a compression check and all cylinders were low (around 120psi on a cold engine that hadn't been cranked in 2 weeks) but I am not sure how accurate my gauge is. I will check my 2wd this weekend to see what that reads. I also noticed that even though all cylinders were fairly even, #1 plugs were black while the others looked like they should. Not sure if that cylinder isn't firing properly or if the valves need adjusting, planning to do that regardless. I would think if it was the valves way out of adjustment the compression would have been lower on that cylinder. I may just swap the wheels and tires from my other 4x4 720 and take it up the road since they are factory size but they are VERY dry rotted and it doesn't seem like the safest thing to do lol. Here is a pic of the truck.

It was the relay, back up and running in minutes.

thanks Mike that'll save me some troubleshooting time.

I bought another 720 two weeks ago, (I think I may have a problem lol), it's an 86 4x4 ST and the body is in really good condition. The hope was that I could fix the exhaust and drive it for a while and slowly work on it. I have another truck that is the exact same color that I had started another thread on and will continue with progress on this truck in that thread since I'll use parts from both to make one good truck. Anyway, It had a really bad oil leak that appeared to be coming from the filter, i checked it and it was loose so I figured all was good. After changing the oil and filter, oil is still leaking pretty bad around that general area so hopefully it's just the sending unit. After that I went to change the transmission fluid and this crap fell out and there was a LOT of metal shavings on the magnet. So the transmission has to come out and have at least one bearing replaced, luckily I have a spare from the other truck so I'll just use that for now and fix this one later. Was hoping not to have to pull the transmission but I guess that's how it goes. After changing the oil and driving it up the road the engine also has a little bit of a rattle, especially as the RPMs get higher so I'll have to see what that is. I am wondering if the previous owner didn't put something in the oil to try and make the engine a little quieter because the oil didn't smell like normal used motor oil when I drained it. Also went to change the drivers side front wheel bearing only to realize the automatic hub internals were in bad shape with metal shavings and really worn parts. Once again, it pays to have more than one truck 🙂 Then after realizing all of that, I got in my daily driver 2wd 85 720 to run to Lowes to get something and the fuel pump went out on it before I even got out of the driveway. I just went inside, took a shower, and decided to call it a day. Figured maybe I shouldn't touch anything else lol.

You may have better luck finding a decent bed off another truck. I got lucky and scored this beauty from a scrap yard not far from me over two years ago. It's been sitting where it's at behind my shop ever since waiting for me to find a use for it. It's in the best condition of any Nissan bed I have ever seen, at least that wasn't on a restored vehicle. It had a shell on it most of it's life so the inside is in really good shape as well.

same here

This is one of the things I like about living in NC. Vehicles 35 years and older do not require any type of inspection. 🙂

It's the box to the left of the blower motor. Since you are trying to get the AC working it's probably a good idea to take that all apart anyway because there is no telling what's in there. Trucks this old tend to have gotten leaves, trash, mouse nests, etc in there over the years. Clean it out real good and use something to clean the evaporator off as well before reassembly.

I used this product to "paint/dye" the center console lid black on my daily driver 720. Has anyone on here tried the blue to see how well it matches the factory blue interiors? I have found that this stuff holds up very well. My center console lid was sprayed a few years ago and I rest my elbow on it everyday and you still can't tell it wasn't originally black.

Price is high but some people are willing to pay high prices for certain things so I figured I would share this. I just saw it on Facebook Marketplace.