Teekass Posted June 27, 2007 Share Posted June 27, 2007 I was involved in a fuel gauge thread a while back, and thought I would post my findings from the fuel gauge I just bought. I have a '77 2+2. I removed my sending unit, and it tested at 88 ohms empty and 10 ohms full. I bought Auto Meter's #4815 which is 73 ohms empty and 10 ohms full (they also have other styles with that ohm range). With the gas tank completely empty, the needle points at the E (not the yellow E "mark", but the white letter E). The needle was just above the peg. I added one gallon at a time, and the needle didn't move (from pointing at the E) until I added 4 gallons. With 4 gallons in the tank, the needle pointed between the E and the yellow E mark. 5 gallons was just below the yellow E mark. 6 gallons, the needle pointed at the yellow E mark. 9 gallons = 1/8th tank 11 gallons = 1/4 13 gallons = 1/2 15 gallons = 3/4 16 gallons = F It works in the correct direction, but it's not linear and is unuseable with less than 4 gallons. I'm still happy with it though. Quote Link to comment Share on other sites More sharing options...
Dat260 Posted June 27, 2007 Share Posted June 27, 2007 Hi Teekass, Thank you for doing this and posting it. I too was following the fuel guage thread. It's good to know you still have 6 gallons left when it points to empty. Ari, Quote Link to comment Share on other sites More sharing options...
Daeron Posted June 27, 2007 Share Posted June 27, 2007 Maybe I am displaying my ignorance (I cannot recall exactly what the entire float assembly looks like) but couldnt you just bend an arm to get something of a calibration? You would just need to find a way to maybe extend the arm, and give it a slightly different angle..? I don't know, its a thought. Quote Link to comment Share on other sites More sharing options...
MrFancypants Posted June 27, 2007 Share Posted June 27, 2007 Did you test your stock fuel sender to make sure that it delivers a linear signal to the gauge? Not that Im saying the Autometer gauge isnt at fault -- they havent been the greatest quality in my experience. - Greg - Quote Link to comment Share on other sites More sharing options...
het976 Posted June 27, 2007 Share Posted June 27, 2007 Could you put a resistor in the circuit to make it more usable at the lower end? Quote Link to comment Share on other sites More sharing options...
aziza z Posted June 27, 2007 Share Posted June 27, 2007 nice. But has anyone ever found a diffrent sender that can be modified to our tanks? Thats kinda what im trying to do right now. I already have a 0-90ohm fuel guage. Quote Link to comment Share on other sites More sharing options...
Teekass Posted June 27, 2007 Author Share Posted June 27, 2007 Hi Teekass,Thank you for doing this and posting it. I too was following the fuel guage thread. It's good to know you still have 6 gallons left when it points to empty. Ari, You're welcome! I feel the same way about the 6 gallons. As thirsty as mine is, at 6 gallons, it's time to think about getting fuel anyway. Quote Link to comment Share on other sites More sharing options...
Teekass Posted June 27, 2007 Author Share Posted June 27, 2007 Did you test your stock fuel sender to make sure that it delivers a linear signal to the gauge? Not that Im saying the Autometer gauge isnt at fault -- they havent been the greatest quality in my experience. - Greg - Great point Greg. No, I sure didn't check to see if the sender was working linear. I would bet the 30 yr. old sender would be to blame (for not being linear) before the fuel gauge. I still don't think the gauge would give an indication until it had a few gallons in it though, since it would be more than 73 ohms. I'm definitely not complaining about the Auto Meter gauge. It gives me the information I need, now it's up to me to get use to the way it works.....I remember a post from Larry (COZY Z COLE) where he said that his fuel gauge works backwards, and he likes the looks he gets when he stops for gas when the gauge reads full ! Quote Link to comment Share on other sites More sharing options...
Teekass Posted June 27, 2007 Author Share Posted June 27, 2007 Maybe I am displaying my ignorance (I cannot recall exactly what the entire float assembly looks like) but couldnt you just bend an arm to get something of a calibration? You would just need to find a way to maybe extend the arm, and give it a slightly different angle..? I don't know, its a thought. Could you put a resistor in the circuit to make it more usable at the lower end? I guess the above ideas could be worth a try...although I don't know that much about resistors. My gas tank needs to be "Renu'd." When I have that done, I'll try to get a good sending unit and see if that works any better (just need to do some "searching" and find out where to get one). My guess (after reading Greg's post) is the sender is the reason for the gauge not being linear......I hope Datsun didn't make them work that way on purpose! Either way though, I can still use it the gauge the way it is. Quote Link to comment Share on other sites More sharing options...
Teekass Posted June 27, 2007 Author Share Posted June 27, 2007 nice. But has anyone ever found a diffrent sender that can be modified to our tanks? Thats kinda what im trying to do right now. I already have a 0-90ohm fuel guage. I've read where people have the same ohm range gauge as you, and the gauge works fine....just backwards. Seems like I also read where someone sent their gauge back to the factory and they changed the linkage in it so that it reversed the way the needle worked. If it's an Auto Meter, I've been impressed with their customer service and warranty. I'd bet they would work with you on it. Quote Link to comment Share on other sites More sharing options...
aziza z Posted June 28, 2007 Share Posted June 28, 2007 I've read where people have the same ohm range gauge as you, and the gauge works fine....just backwards. Seems like I also read where someone sent their gauge back to the factory and they changed the linkage in it so that it reversed the way the needle worked. If it's an Auto Meter, I've been impressed with their customer service and warranty. I'd bet they would work with you on it. alright thanks. i will give them a call and we'll see. Quote Link to comment Share on other sites More sharing options...
ZXRockie Posted July 11, 2007 Share Posted July 11, 2007 My problem is a whole new thing. I'm planning on using a 240sx cluster with speedo and tach calibrated to work with my engine and the temp gauge will work also. the only gauge left out is the fuel guage and this is the ohm measurements 240 Ohms Empty, 33 Ohms Full. Where can we rebuilt our sending unit and get it calibrated at the same time? Quote Link to comment Share on other sites More sharing options...
Teekass Posted July 12, 2007 Author Share Posted July 12, 2007 My problem is a whole new thing. I'm planning on using a 240sx cluster with speedo and tach calibrated to work with my engine and the temp gauge will work also. the only gauge left out is the fuel guage and this is the ohm measurements 240 Ohms Empty, 33 Ohms Full. Where can we rebuilt our sending unit and get it calibrated at the same time? I'm sending my sending unit to http://www.tristarrradiator.com/Untitled-8.html to have it rebuilt and hopefully make it measure more accurately throughout its range (it seems to work correctly empty and full, just not linear between the two). I talked to the owner Dan, who said the charges to rebuild a sending unit are normally around $100.00. He also said sending units can be adjusted a bit, but not to whatever value you want. I measured my sending unit, and it was 88 empty and 10 full. The fuel gauge I have is 73 empty and 10 full. He thought mine were probably close enough to be calibrated to work together. What are the ohm measurements of your sending unit, and are they close to 240-33? I'll post my findings as soon as I get my sending unit back. Quote Link to comment Share on other sites More sharing options...
ZXRockie Posted July 18, 2007 Share Posted July 18, 2007 I'm sending my sending unit to http://www.tristarrradiator.com/Untitled-8.html to have it rebuilt and hopefully make it measure more accurately throughout its range (it seems to work correctly empty and full, just not linear between the two). I talked to the owner Dan, who said the charges to rebuild a sending unit are normally around $100.00. He also said sending units can be adjusted a bit, but not to whatever value you want. I measured my sending unit, and it was 88 empty and 10 full. The fuel gauge I have is 73 empty and 10 full. He thought mine were probably close enough to be calibrated to work together. What are the ohm measurements of your sending unit, and are they close to 240-33? I'll post my findings as soon as I get my sending unit back. I have the stock sending unit, I haven't measure the ohms, but I'm very sure is the same as yours. thanks for the website ... I guess i need to work the gauge intead of the sender. a resistor or something... Quote Link to comment Share on other sites More sharing options...
Teekass Posted July 18, 2007 Author Share Posted July 18, 2007 I guess i need to work the gauge intead of the sender. a resistor or something... Thats beyond the extent of my electrical knowledge . I've read posts by Pop N Wood and others who talked about formulas to get the sending unit ohms closer to what the gauge needed.....I'll try to dig them up. Does your gauge manufacturer make a 73-10 ohm fuel gauge? I can't recommend you get another gauge just yet though because mine hasn't worked correctly, but if rebuilding the sending unit fixes my problem then getting another fuel gauge may be easier for you than doing the resistor thing. My gauge worked correctly at empty and full, it just didn't work well in between the two. I should have it back the first of next week, and I'll post my findings. Quote Link to comment Share on other sites More sharing options...
Teekass Posted July 27, 2007 Author Share Posted July 27, 2007 Did you test your stock fuel sender to make sure that it delivers a linear signal to the gauge? Not that Im saying the Autometer gauge isnt at fault -- they havent been the greatest quality in my experience. - Greg - Well Greg, you're experience was right. It seems the Autometer fuel gauge isn't working correctly. I just got my sending unit rebuilt, and it's exactly 73 and 10 ohms. At half throw of the float, it's 35 ohms......I guess the fuel gauge should be around 42 ohms, so thats pretty close. 1/4 and 3/4 is pretty close to what it should be also. I hooked it up and tested it, and the fuel gauge did that same thing it did before (doesn't move off E until way late, then goes up to F really quickly as the arm approaches the full up position. I should have tested the fuel gauge with resistors before having my sending unit rebuilt. A couple of tests with 10 and 22 ohm resistors quickly told me the fuel gauge was jacked up . Oh well, live and learn....at least it's still under warranty. Quote Link to comment Share on other sites More sharing options...
MrFancypants Posted July 27, 2007 Share Posted July 27, 2007 That's a bummer, Chris. Oh well -- at least your sender is good for another 30 years now - Greg - Quote Link to comment Share on other sites More sharing options...
Tanman280z Posted May 6, 2011 Share Posted May 6, 2011 Im still having trouble with my sending unit. I may just need a new one though, but at $225 + shipping for a 77' sending unit, I might as well buy a fuel cell that comes with a new sending unit that will work with my new $130 autometer guage. Let me know if anyone found any tricks to use another sending unit from a different car. Quote Link to comment Share on other sites More sharing options...
crazyoctopus Posted May 6, 2011 Share Posted May 6, 2011 http://www.egauges.com/vdo_ind.asp?Type=Fuel_Level&Series=Z_Series&PN=ATM-2642 73 Ohm empty/ 8-12 Ohm full. pretty damn close. Quote Link to comment Share on other sites More sharing options...
Dunlop Posted May 6, 2011 Share Posted May 6, 2011 How do you test the stock sending unit? Also how to you wire it? I have everything ready to go even with the resistor, but i dont know how you wire the sending unit. please help Quote Link to comment Share on other sites More sharing options...
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