Kegomatix

Nope, it seems to be running exactly as it did before the light came on, which is really well. And it has the stock carb.

Thanks for the replies. Yes it's next to the battery light, says sensor. I've disconnected the battery for over 30 minutes and it came back. Is there any way to tell if the 02 sensor is bad other than just replacing it?

My buddy (well rather a buddy of a buddy) took the 720 mudding in my back field. It sounded like he had it pinned down at redline the entire time.... Anyhow, the sensor light kicked on but it doesn't seem to be running any different. I can't imagine there would be too many possibilities on an 86, and the 02 sensor was replaced pretty recently. Could it be anything else or is it pretty much only tied in to the 02 sensor?

I figured it out, it was the fuse block. I unscrewed it and just by moving it around some everything started working again on and off. Got it in a perfect spot then screwed it back down and everything has worked ever since. I still need to go through all the wiring down there, I might have a chance this weekend because obviously there is a loose connection or some corrosion causing a bad connection. Been driving it around no issues, just got my first gas mileage estimate and this is all in town/back roads driving and it got me 25 mpg. Not sure how these trucks are supposed to do but I'm really happy with that. I'm used to getting about 13-15.

Checked all the connections, everything seems to be fine and there is continuous power throughout. Now, I sat down in the drivers seat, and maybe in a bit of frustration smacked the fuse block a few times. Battery light turned off and my gauges started working again. Tried the blinkers again, and I can hear the blink a couple times, and it the battery light starts to flash. Then the gauges die again. There has to be a short or bad connection somewhere tied in with the turn signals. Any idea where I can start there?

No I started having the issues first, then took them apart. This truck ran without any issues until I did some regular maintenance to it. Thanks for the help, I'm gonna go check them right now.

Oh yea also forgot that when I fire it up, at first the battery light doesn't come on. Temp gauge fuel gauge and blinkers or still in-op. As soon as I give it a little gas the battery light comes on. It gets brighter the higher the RPM. First fired up with the battery light off the alternators output is 12.5V. When I rev it a little and the battery light comes on it jumps to 14.5V and remains there until I shut it off. Is it over-charging? I understand that 15V + could mean the voltage regulator went out. So I'm not sure if 14.5V is correct or too high.

Sorry, I forgot to mention that I disconnected each of those and made sure as best I could that all the contact points were cleaned up. Clipped them back together firmly and they seem to be good.

Oh, and because it's my first post, here's the beauty right here... And then my usual daily driver, that prompted me to buy the little gas saver. I'm no stranger to Datsun/Nissan, have literally owned dozens of them. Just a stranger to the pickups.

Just bought an 85 720 from my dad for $250. Pretty solid truck overall, biggest issue was that he severely neglected the maintenance. In the 4 years that he owned it, he did NOTHING, and yes, that includes oil changes. But it also never gave him any troubles at all. Never broke down and was incredibly reliable. I drove it the half hour home, problem free. The thing drives and shifts like new, no issues. Well, then I did the maintenance that it has needed for so long. Changed the oil, new valve cover gasket (old one was leaking) plugs, wires, cap and rotor. Fuel filter and air filter (had been running for who knows how long without one). Rear diff fluid, serviced the transmission, changed out brake fluid and clutch fluid. Flushed the radiator (and it reeeally needed it) and filled up with antifreeze. I think that's all. So bear with me, kind of a long story but I feel everything should be included to help me troubleshoot. After all the work I go to fire it up, thinking that it is going to run even better from all the much needed love. It fires right up and sounds better than ever. About 45 seconds in, it starts stumbling and eventually dies. Wouldn't start back up, verified it had spark so I go to check for fuel and of course, it's not getting fuel anymore. After some research I find that the fuel pump relay is a common problem and seemed to fit my symptoms so I buy a new one, and it works.. Sort of. So I go through all the ground connections from battery to fuel pump and clean them up good, that works and the truck runs again. It's running, and it seems to be running great. Only problem is now my battery light is on, fuel and temp gauges stopped working, and my turn signals don't work. WTF?! Another day of trying to figure this out, I unhook the negative on the battery while it is running just to see if the alternator was putting out enough charge to keep the system running. It is, with no issues, so I hook it back up. Voila! The gauges started working again! Everything seems normal, until I try the turn signals. Everything died again. Disconnect the negative and reconnect then all is well again. I even took it down the road and was able to use the signals. Get back home and park it for a while then go back to try again, and they're not working. Disconnect and reconnect, didn't do the trick this time... I am so confused by this! I've gone through every connection and they all look pretty free of corrosion. I am missing the fuse box cover so I don't know what fuse is for what. I have tried researching this issue but haven't found anything similar to what I'm experiencing. Sorry for the long post, I hope somebody has time to skim through it and help me out. Thanks in advance.