Hi everyone! I recently found and purchased a 1984 Nissan 720 4x4 (gas, manual transmission) pickup locally and drove it home. Everything seemed mechanically sound and it drove great at speeds up to 110km/h on the highway and I got it home no problem. I had always intended to clean and fix it up a bit, and that started pretty quick as I had only driven it around for 80kms or so when I went to start it and got halfway down the alley and it sputtered out and died. It started again but only went a few yards back to my property and died again. So I began to check it out and looked online for tips.

The engine cranked but wouldn't start, so checked the plugs and they all passed for spark, pulled the fuses and everything looked good. Noticed that I couldn't hear any hum from the fuel pump, and also read online that the fuel relay switch is problematic and could be the issue. I pulled the relay and found that there was rust on some of the solder connections and the board .. and decided to replace that with an OEM one I found new on ebay. I also ordered the OEM fuel pump as well figuring I would likely have the problem beat at this point.

With the key in the ON position, I checked for voltage to the fuel pump and it was good. Drained the gas tank, changed the fuel filter and installed the fuel pump and made sure to get a good ground connection to the frame. Added about 10 liters of midgrade to the tank and figured that might be it. Turned the key after everything was hooked up and heard a whir from the fuel pump, and some clicking from the passenger side where the fuel relay is. Moment of truth, I tried to start it but no luck as it still just cranked but didn't fire. (Also during this process, I had noticed that if I added a small amount of gasoline straight into the carb, the engine would fire up and run for a short time and die out. So I'm thinking I'm close ..)

That's where I'm at now. I haven't checked the fuel pressure yet (have to get a gauge) so I figure that's next. Was also thinking I'll check around the fuel filter and pump connections to see if there's any gas getting through. I feel that I'm very close to getting it starting again but any help would be greatly appreciated!

Also does anyone use a different fuel filter than the standard plastic OEM one? I was thinking of maybe getting a larger metal-style and maybe that will help.

Cheers everyone and thanks for the tutorials and great discussion on here .. I've already found it a great resource for this truck (and my previous hardbody)

Andy

How does the carb look? If its all gunked up with old bad gas residue that could be your problem right there.

When I had a look with just the air cleaner off, it seemed to have a bit of gum/residue on the throttle valve opening .. I didn't think it was a lot but I poured a bit of Seafoam in there in between several times pouring some gas inside and starting it. I thought the fuel might take a bit to work it's way down the lines but it didn't seem to work. I also added some Seafoam to the gas in the tank when refilling it. I figure maybe I'll get some Gunk Carb Cleaner or similar and do a more thorough job of cleaning it up?

Also noticed at the fuel filter, the filter didn't look like it was getting any gas from the tank, as it sat 3/4 full before and after several attempts at starting. I think I'll check those lines as well and make sure the gas is making it's way from the tank to the filter and beyond. It just seems like there isn't any gas passing through the filter ..

Got it started! I took a look at the line between gas tank and the fuel filter and nothing was coming out .. used a syringe to see and barely any gas came out. Took a closer look after taking that hose out and the hose was clogged up. Replaced that section and after that turned the key to on and took a look .. the fuel filter was rushing to full! Ran around and got in, started it right up. A bit of grey smoke for a while but I think that is the seafoam? Probably helped to clean up the carb a bit too

Nice! 720 lives Look forward to reading and contributing a bit here .. cheers