Rembrant Posted September 3, 2019 Author Share Posted September 3, 2019 Generally, filling problems are caused by the neck vent collapsing, or being kinked or out-of-place. There should have been a steel support in the tank's fill nipple to keep the bottom of the vent tube up where it belongs. Did you insert the tube into that support? I suppose this is a stupid question, but what happens if you remove the plastic vent tube from the filler neck all together? If you ran the gas nozzle slow, theoretically it would be better without the vent tube, right? The vent tube is just to help you fill the tank at a faster rate? I'm wondering if that little metal support in my new tank was too big and has allowed the plastic vent tube to push further into the tank?...Hmmm... I'm going to check that, and if need be I'll bend that little support a little bit to make sure the vent tube stays high. Link to comment Share on other sites More sharing options...
Gary Lewis Posted September 3, 2019 Share Posted September 3, 2019 Generally, filling problems are caused by the neck vent collapsing, or being kinked or out-of-place. There should have been a steel support in the tank's fill nipple to keep the bottom of the vent tube up where it belongs. Did you insert the tube into that support? I suppose this is a stupid question, but what happens if you remove the plastic vent tube from the filler neck all together? If you ran the gas nozzle slow, theoretically it would be better without the vent tube, right? The vent tube is just to help you fill the tank at a faster rate? I'm wondering if that little metal support in my new tank was too big and has allowed the plastic vent tube to push further into the tank?...Hmmm... I'm going to check that, and if need be I'll bend that little support a little bit to make sure the vent tube stays high. They say that no question is stupid if you don't know the answer. And I sure don't know the answer to that one. But I'll hide and watch to see the results. Link to comment Share on other sites More sharing options...
Steve83 Posted September 3, 2019 Share Posted September 3, 2019 ...what happens if you remove the plastic vent tube from the filler neck all together?It's been decades, but I vaguely remember trying that, and filling being AGONIZINGLY slow. But that's the worst that can happen - give it a try, and let us know what you observe. Link to comment Share on other sites More sharing options...
Randy Posted September 4, 2019 Share Posted September 4, 2019 Gentlemen, I installed a new fuel tank this past winter (Spectra Premium # F14A 16.5 Gallon), and a brand new sending unit (Spectra Premium FG75A). I tested the sending unit before I installed it in the tank, and it stroked the fuel gauge with no issue. So now for the past few weeks driving the truck, the gas pump cuts off and the fuel gauge only shows 1/2 tank. I don't know how much fuel is in there...I drive it until I hits Empty, and then refill it...today it took 8 gallons. How did it work before the last few weeks? I ask because I installed a new tank and the same sender that you installed. The first fillup took a full 16 gallons (the 5ish were put in at my friend's hangar and the 10ish we put in when we drove to town) but the gauge didn't read. I was not as smart as you and didn't test it before I installed it. So I managed to remove it without dropping the tank thinking I'd confirm that the sender was bad. But it worked just fine outside the tank. I bent the wire a bit to get it to register higher; now it reads 1/2 tank when I fill up, but I never put more than about 7 gallons in because it feels so weird driving on E, even though I suspect that when I get to E I still have another 8 gallons. Link to comment Share on other sites More sharing options...
Gary Lewis Posted September 4, 2019 Share Posted September 4, 2019 Gentlemen, I installed a new fuel tank this past winter (Spectra Premium # F14A 16.5 Gallon), and a brand new sending unit (Spectra Premium FG75A). I tested the sending unit before I installed it in the tank, and it stroked the fuel gauge with no issue. So now for the past few weeks driving the truck, the gas pump cuts off and the fuel gauge only shows 1/2 tank. I don't know how much fuel is in there...I drive it until I hits Empty, and then refill it...today it took 8 gallons. How did it work before the last few weeks? I ask because I installed a new tank and the same sender that you installed. The first fillup took a full 16 gallons (the 5ish were put in at my friend's hangar and the 10ish we put in when we drove to town) but the gauge didn't read. I was not as smart as you and didn't test it before I installed it. So I managed to remove it without dropping the tank thinking I'd confirm that the sender was bad. But it worked just fine outside the tank. I bent the wire a bit to get it to register higher; now it reads 1/2 tank when I fill up, but I never put more than about 7 gallons in because it feels so weird driving on E, even though I suspect that when I get to E I still have another 8 gallons. Make sure your tank is grounded. And, to test your gauge, ground the Dark Blue/Yellow for the front or Yellow/Light Blue Hash for the rear. With the key on the gauge should go to Full. Link to comment Share on other sites More sharing options...
Randy Posted September 4, 2019 Share Posted September 4, 2019 Make sure your tank is grounded. And, to test your gauge, ground the Dark Blue/Yellow for the front or Yellow/Light Blue Hash for the rear. With the key on the gauge should go to Full. I tested with the sender connected to the cable after I removed the sender from the tank, the meter goes E <> F in concert with moving the sender. I also tested it using resistors across the cable contacts. 22 ohms (a number I found on one of your posts) puts it right at 1/2 tank. I also tested the sender with an ohm meter. Overkill, perhaps, to make up for my complacency when I installed it the first time. I plan to get back at it soon. The first step might be to find out just how much gas I do have in the tank. It's a bit harder now that I finished my Duraspark II conversion and gas mileage increased by 50%. Link to comment Share on other sites More sharing options...
Randy Posted September 4, 2019 Share Posted September 4, 2019 I tested with the sender connected to the cable after I removed the sender from the tank, the meter goes E <> F in concert with moving the sender. I also tested it using resistors across the cable contacts. 22 ohms (a number I found on one of your posts) puts it right at 1/2 tank. I also tested the sender with an ohm meter. Overkill, perhaps, to make up for my complacency when I installed it the first time. I plan to get back at it soon. The first step might be to find out just how much gas I do have in the tank. It's a bit harder now that I finished my Duraspark II conversion and gas mileage increased by 50%. Would the tank ground influence the meter since the meter cable gets its return through the cable? Link to comment Share on other sites More sharing options...
Gary Lewis Posted September 4, 2019 Share Posted September 4, 2019 Would the tank ground influence the meter since the meter cable gets its return through the cable? The schematic below shows the senders grounding via ground G701, which is on the firewall behind the radio. So I was wrong about checking the tank for being grounded as the ground comes through the cable. Sorry. Link to comment Share on other sites More sharing options...
Steve83 Posted September 4, 2019 Share Posted September 4, 2019 Would the tank ground influence the meter since the meter cable gets its return through the cable? What do the battery terminals look like? https://supermotors.net/getfile/723279/thumbnail/07done.jpg Link to comment Share on other sites More sharing options...
Randy Posted September 4, 2019 Share Posted September 4, 2019 The schematic below shows the senders grounding via ground G701, which is on the firewall behind the radio. So I was wrong about checking the tank for being grounded as the ground comes through the cable. Sorry. sorry? no need for that. Thanks for all the great stuff on this site. Link to comment Share on other sites More sharing options...
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