Tekira Posted July 23, 2004 Share Posted July 23, 2004 Hi, I have narrowed my problem down to the tank. My 260, triple 40 mikunis rear pump only with regulator before carbs, started to "jump" when i gave it gas, not enough fuel getting to carbs, so i changed out my rear electric pump and filter from a 2.5-4psi pump to a 5.5-9psi pump and now it sucks all of the gas out of the filter between the tank and pump. There is just not enough gas getting form tank to the pump. Is there some kind of in tank filter getting cloged or somthing? I have taken my carbs apart and changed out everything in fuel system and sprayed lines and jets with compresed air. The only thing that has not been serviced on the fuel system is the tank. Quote Link to comment Share on other sites More sharing options...
2126 Posted August 3, 2004 Share Posted August 3, 2004 Tekira, it seems as though you have found the sourse of your problem by the process of elimination. It's likely that there is some sort of crud restricting the flow, at the tank outlet, to your filter and pump. These old cars are good candidates for this, considering their age and all. The fun part is trying to get the crud out, short of removing the tank and having it reconditioned. Remember, the outlet is about 3/16" I.D. and it doesn't take much to restrict it. I've read about trying to back flush the tank through the outlet, with the tank drain open, using a non flammable liquid (no water or oils) with sucsess. If your lucky enough to have access to an illuminated fiber-scope that's fuel proof, you can do a visual inspection either through the fill spout or through the drain plug. Anyway, it sounds to me as though you have some crud in there that need to be removed. Oh the joys of an old car!!! Good luck and let us know what happens. Quote Link to comment Share on other sites More sharing options...
Tekira Posted August 6, 2004 Author Share Posted August 6, 2004 Well i have spent some money on this tank trying to get it fixed and still no results. I droped it had it cleened and boiled. i even blew off the filter sock off the end of the send pipe. That helped at least i can drive it around. If i let it sit at idle for 3min the car chokes and dies and when i drive it in traffic same thing. I am going to test the system to see if it is the tank or not causing the problems. I will just take the send line, disconnect it from tank and put in a gas can. That way if it runs good i know the tank is crap. Also as i said before i am running a 5.5 to 9 psi pump but i am only getting 2 to 3 psi at the carbs! The gas cant loose that much pressure. Its sucking air instead of gas because something is block the feul flow in the tank. the car "hicups" and the fuel filter is always almost empty. Looks like ill be looking for a new gas tank! Quote Link to comment Share on other sites More sharing options...
Tekira Posted August 11, 2004 Author Share Posted August 11, 2004 Well i fixed it as good as i can for now. I took off the drain plug on the right front of the tank a screwed a 5/16 90 degree brass fitting in its place and ran a fuel line from there to the pump and damn if she doesnt run good! I put the 2.5-4 psi pump back in and drove her around and no more atalling in trraffic and pulls hard through the gears. To give you an idea ov how bad my prob was when i drained the tank by turning on the pump and running a fuel line to a can the fuel would pulseate out of the line instead of a steady line of gas. It took about 25 min to drain 6 gal of fuel. Sheesh! Well thx guys. Quote Link to comment Share on other sites More sharing options...
namz7791 Posted August 11, 2004 Share Posted August 11, 2004 Tekira - glad to hear that you got it going! I am facing a similar issue on my 77 280Z. Does the 5/16" fitting screw into the metric threads or did you have to tap them? Is this something that could be accomplished with the tank in the car? Did you continue to run the fuel line in the stock location or did you flatten it out and go under a non pivoting point on the rear suspension? Was a high flow fuel filter required between the pump and the tank? Thanks in advance for your insight! Quote Link to comment Share on other sites More sharing options...
Tekira Posted August 12, 2004 Author Share Posted August 12, 2004 When i said 90 degree 5/16 fitting i ment the NPT was 5/16 the thread size is 1/4. Its easier to find a 1/4 thread to a 3/8 NPT 90 degree wich also works. The drain plug has 1/4 size threads so no tapping just screws right in! And yes you would want to use a fuel filter before the pump for obvious reasons. The plug is located (if u are looking at the rear of the car) front right bottom of the tank so its very easy to put in with out dropping tank. And just run a fuel line straight from the new NPT to a filter then to your pump. AND MAKE SURE U BLOCK OFF YOUR OLD SEND PORT ON THE TANK!!! I forgot and gas came out!!! Just take a 5/16 fuel line and insert a 5/16 or 1/4 blocking cap and clamp in down. Ill take a pic of it to show u my installation. Good Luck!!! Any Car parts store carries the fittings Quote Link to comment Share on other sites More sharing options...
Guest 350zgto Posted August 30, 2004 Share Posted August 30, 2004 I want to use the drain outlet as the tank to pump line. What kind of fitting did you use on the tank threads? They do not appear to be pipe threads. Must be metric, I know it's 1.25 threads per inch. I want to use a 3/8ths hard line. Thanks Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.