datsundave Posted May 9, 2011 Share Posted May 9, 2011 Hey guys and gals, I just bought another z this time a 260. It is an automatic don't know that it matters bought it drove it for a day ran great no problems. At the end of the day I put SEA FOAM in the gas tank and filled up. Stop buy a store came back out to find gas leaking from tank. leaked out to 1/2 tank. The next day I drove car for about 40 min. When I started to pass someone I lost all power and when I let off the gas power came back. Parked car latter drove about 10 min. and the car did the same thing. Now that car looses power and dies after about 5 min. My first thought was vapor lock, however it starts right up and will run until I put it under load. Can anyone help? Has anyone else had this happen to them. It could be one of the fuel pumps should I here the electric fuel pump buy the tank. Please positive post only. The 260z does have flat top su's I know that someone is going to be an ass an tell me that someone else had a post about this however, I did several searches and did not finding any real help. I also know that many will tell me to change the carbs and while that may be a good idea not sure that is the problem. I don't know all the answers or I would not beasking for help. We are all car guys and here to help each other, all of us have something to give and we all will need to take at some point. Quote Link to comment Share on other sites More sharing options...
Pharaohabq Posted May 9, 2011 Share Posted May 9, 2011 Well my guess is that the seafoam you put in the tank knocked loose some old crud in the tank. (thus the leak etc) and now you're car is dying out due to fuel starvation. I would almost guarantee your fuel filter is clogged up. This isn't too much to worry about, though it's very likely you'll need to drain and drop the tank, Get it cleaned out (hot dipped is recommended) then replace the filter, hook it all back up and I bet you'll be good to go... Anyone else got a better diagnosis? Please post what it turns out to be once you get it figured out. Phar Quote Link to comment Share on other sites More sharing options...
datsundave Posted May 10, 2011 Author Share Posted May 10, 2011 Thanks you for the reply I didn't think about the fuel filter, one of those too simple couldn't be that items. I will give that a try. Will see what happens. I was planing on pulling the fuel tank anyway. Could the SeaFoam affect the carbs in a negative way? Thanks Again. Quote Link to comment Share on other sites More sharing options...
Matt K Posted May 10, 2011 Share Posted May 10, 2011 Seafoam shouldn't directly affect them, however any dislodged particulates in the fuel system could wreak havoc with the carbs... Quote Link to comment Share on other sites More sharing options...
Austin240Z Posted May 10, 2011 Share Posted May 10, 2011 Well my guess is that the seafoam you put in the tank knocked loose some old crud in the tank. (thus the leak etc) and now you're car is dying out due to fuel starvation. I would almost guarantee your fuel filter is clogged up. This isn't too much to worry about, though it's very likely you'll need to drain and drop the tank, Get it cleaned out (hot dipped is recommended) then replace the filter, hook it all back up and I bet you'll be good to go... Anyone else got a better diagnosis? Please post what it turns out to be once you get it figured out. Phar I've seen identical symptoms on a lot of cars. Including one case where someones kids put dirt and marbles in the tank. So, Same diagnosis here, however, every instance I've seen has been on tanks with an internal sock filter. Dirt would get stirred up and block up the sock, and once the car stopped, it had a chance to settle again. Usually this would happen in 10-15 minutes, only needed a minute or so before the car could start up again, but then would die out again 5-10 min after that. The S30's dont have an internal sock filter, but it could very well be that a big chunk of rust or dirt(most likely rust) got loosened up and is blocking the feed line that's inside the actual tank on the 260. If it were in the line or filter already..... odds are it would probably stay clogged or clog again within a few seconds to a minute. There's a chance some crud made it's way past the filter and got into the actual carbs, but I'd look more toward the tank for the problem first. I've had 2 Z's with super rusty tanks. Both of which did not allow any flow out of the tank itself. Thanks you for the reply I didn't think about the fuel filter, one of those too simple couldn't be that items. I will give that a try. Will see what happens. I was planing on pulling the fuel tank anyway. Could the SeaFoam affect the carbs in a negative way? Thanks Again. I've sold and used SeaFoam on dozens of different types of cars for a number of years. It wont affect the carbs themselves in a negative way. But it can stir up a lot of dirt and grime gremlins... I personally use the Brake booster line method rather than putting it in the tank 99% of the time mainly because I'm concerned with the oil/carbon build up in the intake manifold and combustion chamber. It's a lot more effective on the carbon build up that way. (sorta like the old water through the carb trick) S30 tanks are great in that they have a drain plug, I'd suggest getting a container, pullin the plug. See what comes out first off. Once it's empty, you can take the fuel level sender out and take a better look inside without having to drop the tank. That's of course if you're not sure that you actually want to drop the tank. Quote Link to comment Share on other sites More sharing options...
Pharaohabq Posted May 10, 2011 Share Posted May 10, 2011 Yeah with the tank leaking it would certainly be a really good idea to drop the tank, though becareful with your hoses, they're liable to be old and brittle, may need to replace some lines, and possibly the rubber part of the fuel filler neck. Let us know what you find out. Quote Link to comment Share on other sites More sharing options...
datsundave Posted May 12, 2011 Author Share Posted May 12, 2011 Thank you everyone for all the help I plan to work on it this weekend I will let you know the outcome. And thank you for only posting positive feedback. Dave Quote Link to comment Share on other sites More sharing options...
Pharaohabq Posted May 17, 2011 Share Posted May 17, 2011 How'd it go Dave? Quote Link to comment Share on other sites More sharing options...
Austin240Z Posted May 18, 2011 Share Posted May 18, 2011 I am also curious to hear the results Quote Link to comment Share on other sites More sharing options...
twofouroh Posted May 18, 2011 Share Posted May 18, 2011 I'm running flat tops on my '74 also, and they're really better carbs IMO, as long as you unhook all the smog crap on the manifold. I think you need to check and make sure the carb pistons aren't stuck in their bores, and that the damper pistons have the correct amount of red ATF in them, though. Either could cause the good idle, no WOT problem you're having. If they are stuck, you can take the tops off and clean them with the carbs still on the car. Be VERY careful with the needles! If you so much as bend them, they are ruined! Don't sand or shine the needles up either, you'll make them run rich. Take off as little metal as possible while freeing the pistons up. If they don't show any signs of recent maintenance, you should probably do a rebuild kit on them. Autozone has kits. There is no sock in the tank, the pickup is just a pipe, as I recall. Also remember that there is a filter inside the factory electric pump as well as the one before it, and it has probably never been replaced. NAPA is the only place I found the external filter with the correct case size - AZ, Advance, and CarQuest all tried to sell me one that was too big to fit in the clip that holds it to the bracket. As long as you're unhooking all the fuel hoses under there, you might as well put back new hose, it's plenty cheap, and 6 feet should do it. Your gas tank leak is probably a broken off vent hose fitting on the tank. It has several (3?) vent hoses, the fittings are just soldered on to the tank, and people will crack the solder yanking on the tank before they figure out there's still a hose attached. Look for a hose coming out just above the seam, on the driver's side, towards the back. I had to pull my tank, and resolder that hose fitting - thanks PO! It's the only hose low enogh to empty half the tank, unless it's the filler hose on the other side. Good luck finding another one if your filler hose is cracked. Anyway, good luck with it! Quote Link to comment Share on other sites More sharing options...
datsundave Posted May 28, 2011 Author Share Posted May 28, 2011 Well Guys I pulled the inline filter it was full of S... when i empty it the fuel came out black. however my other 2 z's are 240's did not realize the electric pump had a filter in it so I had to change that filter as well. I think that I want to put an after market fuel pump on it and get rid of both factory fuel pumps. But it helped. is it true that the electric pump only kick's in when the car is over a so many RPM's on the 260? Quote Link to comment Share on other sites More sharing options...
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