82 720 idles too low and stalls!

[jayceng]

Sorry for the long post just want to give you guys as much detail as possible to help me fix my problem.

I just bought a 1982 datsun 720 and its my first carbureted car. When I bought the car and drove it for a couple days it ran fine. I let the car sit for a day.
First day with problem

The next day I tried to start it and the battery was drained. So I jumped it and let it warm up then tried to drive to work. As I was driving I went down hill and saw my gas gauge go from almost half tank to empty. I thought it would go back up like it would usually do. So I kept driving then it started to sputter so I went to a gas station and out gas. The car wouldn't turn on again so I had to jump it, we let it charge and sit there for a while. Tried to drive it home and it would sputter and almost die out. So I parked it and took the battery to a local auto part store to charge it. They said it was still good. I put it back in my truck and drove home. I took out the alternator and had it tested and it was fine. I later found out that the cable connected to the battery and alternator wire was loose. Turned the car on and it was fine. But them the idle was too low so it started stalling without pressing on the gas. I adjusted the throttle cable to 1500 so it wouldn't die out.

Day 2 of problems

Thought I fixed the problem I started my car for work and it idles way too low and have to press on the gas pedal to keep it on, drove to work and I adjusted the cable again, and carburetor cleaned spray.after work the idle was fine.

Day3 same problem. I warm up the car 30 minutes with my foot on pedal, still stall if I release the gas pedal. While driving to work the idle slowly goes back to 1100-1400 but when I step on the gas hard and put on neutral the idle will drop fast and it would stall, sometimes it'll catch it's self before it stalls,

My question is why is my idle so low even if I mess with the cable and why does it take so long to warm up, also when I drive home from work my car works fine, morning The outside temp is about 55-60 and after work like 70 degrees, and also I notice today that my temp gauge is not working anymore and it use to before all this happened.

[jayceng]

Noob question. Where is the fuel filter in a 82 720? The book says there is 2 and I know where the one by the gas tank is at I'm just trying to figure out where the one by the battery is at.

[foxfan1992]

Just a note here... I'm not the most technical of guys but I do have an '84 Datsun that has given me plenty of 'bonding time' with it not working properly. I too had similar issues where the truck would sputter and die after putting it into gear or occasionally just randomly after working fine for ten minutes or so. What I did was I adjusted the idle speed screw under the air filter to make it idle a bit faster. This fixed my problem, so you can try that.

As for the battery being drained, this has happened to me too. Actually ended up in a fun situation being stuck at the top of a mountain pass awaiting a tow back home because of it. In the end the reason for this happening was because the alternator belt was loose. Once it was tightened it ran with no issues, so check the alternator belt too ;-).

[PEZi]

There aren't 2 fuel filters.... just 2 locations depending on the year. If you found the one by the tank, you found your filter. And the problem sounds to be more than likely a vac leak... not actually a fuel problem. Hope that helps... but vac leaks can take forever to find!