Guest mynameiszhen Posted September 2, 2008 Share Posted September 2, 2008 Hi i am still new to this site but i need some help i have bought a 1972 240z with a L28 few weeks ago, but the engine has a problem. at first the car starts up with absolutely no problem and runs really strong, but after a good ten minutes of running it loses power and will not accelerate, even when i downshift. then i have to turn the car off and wait a few minutes to restart to run again. Also there was once when i was idling on a stop light, the car slowly turn off by itself. please give me advises or ideas of how to fix this problem. thank you so much.! Quote Link to comment Share on other sites More sharing options...
m1noel Posted September 2, 2008 Share Posted September 2, 2008 Sounds like it could be vapor lock. A new fuel pump may fix the problem. Good luck, Mike Quote Link to comment Share on other sites More sharing options...
silver280zx Posted September 3, 2008 Share Posted September 3, 2008 Does your fuel tank have rust in it? I had that problem for a while, and what waws happening was the engine ran and the pump built up pressure, sucking the crap up from the tank into the fuel filter, clogging it up. When the engine is off and the pump isnt running the dirty fuel would back back up into the tank and lines. Quote Link to comment Share on other sites More sharing options...
MatMan Posted September 3, 2008 Share Posted September 3, 2008 I second the tank. Does your L28 have FI or carbs? If its FI, vapor lock is not likely to be happening. I had similar problems. It would run just long enough to get me about 2 miles form my house, then die and not restart. I had my tank boiled and lined, and I have not had that problem since. A radiator shop will be able to help you. Where in CA are you? Quote Link to comment Share on other sites More sharing options...
Guest mynameiszhen Posted September 4, 2008 Share Posted September 4, 2008 it has carbs, and i don't think my tank has rust in it. the engine doesn't always die but it loses lots of power and will not go and it dies once in a while at idling i'm located in LA Quote Link to comment Share on other sites More sharing options...
Guest mynameiszhen Posted September 4, 2008 Share Posted September 4, 2008 Also i have an electric pump that has a kill switch that i must turn on before start engine. does this have anything to do with problem? Quote Link to comment Share on other sites More sharing options...
AK-Z Posted September 4, 2008 Share Posted September 4, 2008 Check/clean in order. (with battery disconnected) (clean. A little di-electric grease helps) 1.tps connector 2.maf sensor connectors 3.ecu connector fuel filter. Quote Link to comment Share on other sites More sharing options...
naviathan Posted September 4, 2008 Share Posted September 4, 2008 Check/clean in order. (with battery disconnected) (clean. A little di-electric grease helps) 1.tps connector 2.maf sensor connectors 3.ecu connector fuel filter. He said it has carbs... Check/replace the fuel filter(s). Doubtful it's the pump because with carbs it would just stumble and die once the bowls emptied so clean and tune the carbs. Outside of a fuel system problem it could be a bad coil that gets weak after it heats up. Quote Link to comment Share on other sites More sharing options...
MatMan Posted September 4, 2008 Share Posted September 4, 2008 If you have carbs, do you run SUs? If you do, there "should be" what are called banjo filters right between the float bowls and the fuel rail. Those may be gooky. Why do you think the tank is clean? Have you had it boiled within the last few years? My theory with the tank is... when the car is originally started, the gunk and grime is at the bottom of the tank, after running the car a bit, the stuff is swished around, and eventually gets to the pickup tube, and restricts the complete flow of fuel. If you shut the car down for a while, the suction holding the clog is cut off, and the junk falls back to the bottom of the tank. My tank was in bad shape. The entire pick up tube was corroded, allowing only a trickle of fuel through, even though I was running BOTH the mechanical and electric FPs. I think after you do the easy stuff like Naviathan said, the tank's your next best bet. Quote Link to comment Share on other sites More sharing options...
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