When full, gauge reads past F, when empty reads between E and 1/8. Can I adjust the needle by adjusting the float on the in tank fuel sending unit? Jack
Now that you know what the parameters are, leave it as is, and fuel up when you get to 1/4 of a tank.
That's what I am doing, just would like it to read more accurate. On this car getting access to tank fuel sending unit fairly simple Getting access to the gauge, not so much, actually PIA. Jack
When I build a car or buy one I run it out of gas, I look at the gas gauge to see where it is and put one gallon in at a time and see when the gauge starts to move off of empty. Know I know how much gas I have left
You didnt say what kind of car you're working on. If you have a Model A Ford, then ,Yes, bending the float arm will solve your problem. Anything that involves battery power to operate, the sending unit is a rheostat, and varies according to level, affecting the gauge needle. Bending the arm or adjusting the float will not really affect where the needle on the gauge falls when full and empty. Your problem is in the gauge, not the sending unit. I agree with the others, they told you how to fix it, and how to live with it. Good Luck.
Hello, Not knowing your type of gas gauge, is there by any chance a fuse is connected or attached to the gauge? We had a similar situation in our last 30 foot sailboat. We were going to another harbor 60 miles away and had filled up the gas tank to the brim prior to starting out. We sailed most of the way and stopped in a nearby harbor to see the level of gas if and when we were ready to power into the last harbor and dock. By the time we got outside of the harbor jetties, the waves were nearing 6 feet and our sailboat plowed through those deep channels and wave swells. It was found out later that that day in the summer was one of the harshest days of weather, swell and winds to hit the So Cal shoreline in ages. The waves in Newport Beach were so strong, causing a national news item about a young lifeguard having an accident in those waves. We did not know that and just sailed until we had to drop the sails due to the strong winds, current and wave direction. So, we started the motor and plodded up/down and across the faces of the waves to get to the other side. When we finally arrived at the next stop as the sun was starting to set, we stopped for gas before entering our dock. The guy just kept pumping gas into the filler for longer than normal. We were surprised at how much the gas tank took. We were running on empty and luckily did not run out of gas in those 6 foot plus waves and currents. When we arrived at the final destination in another marina up the coast, the tank was empty again. We were motoring on fumes, even though the gauge said 3/4 to near full on the gauge. Relying on the gas gauge is usually reliable. Jnaki We did the same thing, although once I checked the gas tank, it looked empty. But, the gauge still read 3/4 full. Upon arriving back to our own Dana Point dock, our mechanic checked things out and said the fuse was blown. Once he put in a new fuse after crawling into the narrow compartment, the gas gauge read full once we went to the gas dock for a fill up. We did not know the sailboat gauge had a fuse. But, it was a simple replacement and back to checking the gauge before we went out open ocean sailing, again. So, since there are plenty of different gauge companies, if your gauge has a fuse, it might be faulty and registering a mis-reading of the actual gas level. YRMV
I use this fuel sender. Order longest size that will fit in tank, with the correct ohm range to match dash gauge. Very accurate and trouble free. https://www.isspro.com/page_Level_Fuel_Senders.php
I have some old Chevys that have electric fuel gauges that it's real easy to bend the needle, to correct a problem like that. But I also have no idea what kind of fuel gauge you have, so this may or may not help you at all. When asking a question, please include all the details....then you might get a useful answer.
It is a 48 DeSoto, using original gauge, but has been converted to electronic by CON2R. The sending unit and gauge have same ohms range. The sending unit float is "universal" and the float rod is adjustable in and out, and can be bent. I think adjusting in and out would be better, if that would make a difference? If I adjust it in or out, which should I do. Needle needs to move from right (F) to left (E). Gauge is rectangular, not round. Jack
Phil, I looked at that one, and I like the concept. Had never seen one in person. Is a simple, remove old traditional sending unit and install this one. Wiring same, a power and a ground? Jack
I worked on my float to get the best I could on a 17 gallon tank. It stays full for 50 miles. I usually fill it a 1/4 and it takes 12/13 gallons. I have a milage book in the glove box on all my cars and know when it’s to 140/150 to fill up.
If you know the gauge and the sender are the same ohms range, then adjusting the float seems like the way to go.
Moparjack44: Perhaps I missed it, but what year car are you working on re: gas guage and sending unit. That unit posted by Phil sure look like an excellent choice. I wonder what it would "read" if it was connected to 6V system. Thanks, JIM
If the float is hitting the tank, then bending the arm would work. You need the float to hit the top of the tank sooner. If the float makes no contact with the tank, then adjusting the stops on the sender itself, or the rheostat contact arm might be needed. You may need to adjust both the arm and the built in stops. Before any bending or adjusting, run the sender from full to empty and compare it to the gauge. It could also be an electrical problem where the ohms don't quite match up, then bending the gauge needle would be needed. It depends on what is stopping the float arm if the ohms are right.
Pull the sender out but leave the wire connected. Run a ground to the sending unit mounting flange. Move the float to where it should be when the tank is empty. Does the gauge read "Empty"? Now move the float to it's highest level. Does the gauge read "Full"? If so, adjust the float so that, when the sending unit is mounted in the tank, it has the full range of movement. If not, then either your sending unit or gauge is at fault. FYI, it's not uncommon for a gauge to read past the full mark, and I'd adjust the float so that the gauge reads empty when you still have a couple gallons in the tank.
Did they use servos for the gauges? If so, might be able to move the needle relative to the shaft. The original gauge has a needle that you can bend... As mentioned, the float arm will only move so far. Since the needle is just offset, and the gauge travel has the correct range, I'd really want to fix the gauge, not the sender.
This unit uses the standard 5 bolt SAE bolt pattern used on cars of the 60's to current. Some manufacturers may have adopted it earlier. I would say most aftermarket tanks use this standard pattern fuel sender. Do you have a part number for your current sender, so I could look at it online? I found the wiring to require no change, just attach to new unit.
These guys like to make this stuff complicated. Bend the float arm so the rheostat reads empty when the tank is empty. My guess is you will need to bend the float arm so the float sits higher, but make sure it doesn't lay the float or the float arm against the tank or the pickup tube. The bend will probably be pretty minor, it may take a few shots at it to get it to read the way you like it reading.
If the sender is already at the end of it's travel when the gauge reads 1/4 tank, then no amount of bending is going to fix it. That's why we're making it complicated...because it's a complicated problem.
Then it would be safe to say the sweep is “most likely” (no guarantee yet) is correct on the gauge. It’s been mentioned already, pull sender from tank reconnect wire to terminal then ground sender to the car via wire. Now run sender arm up and down and compare with gauge still in the dash.
First thing I did. Needle reads past F with arm at full position, reads between 1/8 and E with arm at empty position.
If you can pull out the gauge and take some pictures of it, we might be able to help you figure out how to fix the problem. It's really hard to help a guy when he's working on something that no one else can see!
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