I'm glad it can help you out. Also use the different resistors to get the gauge to read in different positions. The basic test of grounding and ungrounding the sender wire can lead one to think the gauge is good but in reality the tests with resistors will show for sure any additional issues.
just bought a 1970 Nova as a project car for my high school boys and me to work on. It was set up for racing. Am going to remove the fuel cell and electric fuel pump and restore the fuel system back to stock. This video was VERY helpful. Thank you.
Great video thanks almost done with my 67 firebird 455 just getting the little things out of the way and wanted to check on the fuel gauge this video will help me
You're Welcome. It's not a very elaborate system but things need to be right for it to work. Look around under stlnovas on youtube and there are other things I've written about the fuel gauge system.
thank you so much for the video! super helpful! Hoping that my ol' girl gets her gauge back up and going. The guessing game and math all the time is breaking my brain LOL
Thanks for the dislike on 2018-8-20 from a United States viewer. If you can hit the dislike, why can you not say what you dislike ?. Boy gotta love the idiots out there.
You're welcome. Did it help you out ?. Be aware that the tests of grounding and un-grounding the sender wire only gives you so much input. I have found out that if the resistor across the back of the gauge (or built in to some of the newer ones) is bad or not in place, then these two tests of grounding and ungrounding can give you a false impression that the sender is bad so ideally do more tests with different value resistors to mimic what the sender would be at different levels. On a 0-90 ohm system, a 45 ohm resistor should have the gauge reading 1/2 full, while a 22.5 ohm resistor should make the gauge read 1/4 full, and a 67.5 ohm resistor should make the gauge read 3/4 full. A 90 ohm resistor would make it read full. Jim
Awesome I'm going to find me some resistors of same resistance and try it out when my printed circuit board that I broke during removal arrives. Thanks.
You just need to go through some testing and replace or repair what is needed. Start with the basic checking the fuse for the gauge and connection points. Ideally get a shop manual and this might help out too. Don't get a chiltons but an actual GM shop manual.
Henry, You need to ground out the sender wire to see if you can get the gauge to read empty or below. If it does not, then it might just be ONE issue from that test point forward towards and through the gauge BUT be aware that even if you get that working right you still could have a sending unit issue and/or with the sender's ground. To then test further you will need to do some tests like I did WITH the resistors. I used to think that just grounding the sender wire to get the gauge to read empty or below and then leaving it disconnected to get the gauge to read full or above was enough, but it is NOT. A quick search and I think you have a 0-90 ohm sender and if so, get something close to a 90 ohm resistor ( or anywhere from let's say 80 to 100 ohms) and then another resistor close to 45 ohms (or anywhere from let's say 40-50 ohms) and then another one close to 22.5 ohms (or anywhere from let's say 20-25 ohms).
If it is a stock gauge then instead of it being a 0-90 ohm setup, yours should be a 0-30 ohm setup but the basic two tests of grounding out the sender wire going towards the gauge and then leaving it ungrounded and connected to nothing should get it to go from empty or below and then to full or above. If the gauge passes one part of the two tests then I would be thinking a gauge issue and then I would take the gauge out and bench check it. If it does neither and does not move, possibly a power and/or ground issue. Jim
I also have a 68 Nova and the fuel gauge is always at empty. When I pulled out the sending unit wire connector, the fuel gauge was still at empty (it did not go up to full tank as in your example). Does this mean I have a broken wire somewhere? Is the sending unit broken? I've also been under the car and I can't see those two ground points/bolts that you have...?! Btw; the previus owner said the gas gauge worked when he had it, but suddenly it stopped working. Thanks in advance for your help!
If the gauge is working but the wire to the sender is NOT connected to anything, then the gauge should go to full or above. If the sender wire is shorted after the gauge towards the sender in the tank, then the gauge should read Empty or below. It's possible maybe the gauge is not getting power due to a blown fuse in the fuse block or maybe up in the dash. The gauge may also might not be getting a ground. The gauge may actually be broke. The test back by the taillight panel or at the sender in the gas tank should show if there is an issue towards the tank or towards the gauge. If it's not doing anything by doing things on the wire at the tank or taillight panel, then I would be checking fuses and then if things check out there, pull the dash apart to get at th backside of the gauge to verify things and then if all is good there, take the gauge out and bench check it with a 12V power supply.Jim
looks like I'll have to invest in a decent mulit-meter after all. Not the one I got from Big Lots.. This should be the same principle for a 1970 Lesabre right?
A decent meter should be a basic tool for working on cars or for even things around the house. Just like a decent set of sockets or wrenches. Cheap ones will round the heads off nut or bolts and are not built to very tight tolerances. Anyway, yes, the same principle would apply to a 1970 Lesabre. Those should have the 0-90 ohm setup as what is on my 68 Nova in the video. Be aware that the basic unplugging and shorting of the sender wire to ground going towards the gauge can give one a false positive and ideally you should get the resistors to do further checking. While I have seen different issues with the fuel gauge system, most issues seem to be on the sender end BUT one cannot be sure until some tests are done. Jim
+Chris Craft I'm glad you liked it. I've helped many with fuel gauge issues and it's nice with something like this to explain things with pictures instead of just words. Jim
You need to identify the sender wire at the tank or at some connector between the tank and the gauge (or even at the back of the gauge) and then do the basic test with having the ignition switch to the run position and then having the wire to the sender disconnected to see if the gauge reads full or above and then grounding the sender wire which goes towards the gauge to see if it goes to the empty or below mark. I've also found out this test is VERY basic but to confirm the gauge is reading properly is to use different resistors like a 90 ohm, a 67.5 ohm, a 45 ohm, a 22.5 ohm, and some others between the sender wire going to the gauge and to ground to verify it reads about 1/4 full with the 22.5 ohm resistor and then about 1/2 full with the 45 ohm resistor and then about 3/4 full with the 67.5 ohm resistor and about full with the 90 ohm resistor. Most of the gauges have what they call a shunt resistor across the back of the gauge which if bad can throw of the accuracy of the gauge.
This video was very informative. Thank you for posting. This will help me fix the gas gauge on my 74 nova
I'm glad it can help you out. Also use the different resistors to get the gauge to read in different positions. The basic test of grounding and ungrounding the sender wire can lead one to think the gauge is good but in reality the tests with resistors will show for sure any additional issues.
just bought a 1970 Nova as a project car for my high school boys and me to work on. It was set up for racing. Am going to remove the fuel cell and electric fuel pump and restore the fuel system back to stock. This video was VERY helpful. Thank you.
I'm glad it helped you out. I also have other video's and information on a flickr account of mine www.flickr.com/photos/121766713@N04/albums
I hit the "like" button, but I really like videos where someone is talking. Silent films went out in the late 1920's & "talkie's" still rule today.
Great video thanks almost done with my 67 firebird 455 just getting the little things out of the way and wanted to check on the fuel gauge this video will help me
Have a non working gauge and didn't know how to troubleshoot. Your video was very helpful, Thank You.
You're Welcome. It's not a very elaborate system but things need to be right for it to work. Look around under stlnovas on youtube and there are other things I've written about the fuel gauge system.
Great vid and very clear explanations. Thank you for making and posting.
I hope it helped you out.
thank you so much for the video! super helpful! Hoping that my ol' girl gets her gauge back up and going. The guessing game and math all the time is breaking my brain LOL
awesome brother you helped me alot !!!
nice ...and good explanation to the point...thanks
Thank you you made my day
Awesome video! Need to fix it now, guage stuck on "FULL" key on and off.
Who ever said "Silent Movies" went out of style after 1900 & 29????
Thanks for the dislike on 2018-8-20 from a United States viewer. If you can hit the dislike, why can you not say what you dislike ?. Boy gotta love the idiots out there.
StlNovas screw them!! This video saved me a butt load of time! Thanks!!!
Awesome. Thanks for this video.
You're welcome. Did it help you out ?. Be aware that the tests of grounding and un-grounding the sender wire only gives you so much input. I have found out that if the resistor across the back of the gauge (or built in to some of the newer ones) is bad or not in place, then these two tests of grounding and ungrounding can give you a false impression that the sender is bad so ideally do more tests with different value resistors to mimic what the sender would be at different levels. On a 0-90 ohm system, a 45 ohm resistor should have the gauge reading 1/2 full, while a 22.5 ohm resistor should make the gauge read 1/4 full, and a 67.5 ohm resistor should make the gauge read 3/4 full. A 90 ohm resistor would make it read full.
Jim
Awesome I'm going to find me some resistors of same resistance and try it out when my printed circuit board that I broke during removal arrives. Thanks.
Unprotected conecctions are dangerous i always put a little of cover plastic cream in every circuit.
Thanks for the video, have 67 Bonneville. The gauge always reads 1/2 full. Key on or off. Any ideas? Thnks
You just need to go through some testing and replace or repair what is needed. Start with the basic checking the fuse for the gauge and connection points. Ideally get a shop manual and this might help out too. Don't get a chiltons but an actual GM shop manual.
Still answering questions ? My 67 g10 van used to be accurate but now I run out of gas at 1/3 on the gauge. Full tank pegs the needle past full.
Thanks.
Henry, You need to ground out the sender wire to see if you can get the gauge to read empty or below. If it does not, then it might just be ONE issue from that test point forward towards and through the gauge BUT be aware that even if you get that working right you still could have a sending unit issue and/or with the sender's ground. To then test further you will need to do some tests like I did WITH the resistors. I used to think that just grounding the sender wire to get the gauge to read empty or below and then leaving it disconnected to get the gauge to read full or above was enough, but it is NOT. A quick search and I think you have a 0-90 ohm sender and if so, get something close to a 90 ohm resistor ( or anywhere from let's say 80 to 100 ohms) and then another resistor close to 45 ohms (or anywhere from let's say 40-50 ohms) and then another one close to 22.5 ohms (or anywhere from let's say 20-25 ohms).
@@StlNovas thanks for very detailed suggestions. Henry
@@henrytupper6959 Hopefully you will get it figured out. If not, reply back.
@@StlNovas thanks, can’t ck till later in the week.
THANK.YOU SIR
How about when gauge needle goes up to 1/8th and no higher? I've tried everything on my 56 Chevy truck.
If it is a stock gauge then instead of it being a 0-90 ohm setup, yours should be a 0-30 ohm setup but the basic two tests of grounding out the sender wire going towards the gauge and then leaving it ungrounded and connected to nothing should get it to go from empty or below and then to full or above. If the gauge passes one part of the two tests then I would be thinking a gauge issue and then I would take the gauge out and bench check it. If it does neither and does not move, possibly a power and/or ground issue.
Jim
I also have a 68 Nova and the fuel gauge is always at empty. When I pulled out the sending unit wire connector, the fuel gauge was still at empty (it did not go up to full tank as in your example). Does this mean I have a broken wire somewhere? Is the sending unit broken?
I've also been under the car and I can't see those two ground points/bolts that you have...?!
Btw; the previus owner said the gas gauge worked when he had it, but suddenly it stopped working.
Thanks in advance for your help!
If the gauge is working but the wire to the sender is NOT connected to anything, then the gauge should go to full or above. If the sender wire is shorted after the gauge towards the sender in the tank, then the gauge should read Empty or below. It's possible maybe the gauge is not getting power due to a blown fuse in the fuse block or maybe up in the dash. The gauge may also might not be getting a ground. The gauge may actually be broke. The test back by the taillight panel or at the sender in the gas tank should show if there is an issue towards the tank or towards the gauge. If it's not doing anything by doing things on the wire at the tank or taillight panel, then I would be checking fuses and then if things check out there, pull the dash apart to get at th backside of the gauge to verify things and then if all is good there, take the gauge out and bench check it with a 12V power supply.Jim
My gauge jumps up to 1 quarter tank, won't go any higher no matter how much fuel is in it, any advice?
What were your results doing the testing like what I showed in the video ?.
looks like I'll have to invest in a decent mulit-meter after all. Not the one I got from Big Lots.. This should be the same principle for a 1970 Lesabre right?
A decent meter should be a basic tool for working on cars or for even things around the house. Just like a decent set of sockets or wrenches. Cheap ones will round the heads off nut or bolts and are not built to very tight tolerances.
Anyway, yes, the same principle would apply to a 1970 Lesabre. Those should have the 0-90 ohm setup as what is on my 68 Nova in the video. Be aware that the basic unplugging and shorting of the sender wire to ground going towards the gauge can give one a false positive and ideally you should get the resistors to do further checking. While I have seen different issues with the fuel gauge system, most issues seem to be on the sender end BUT one cannot be sure until some tests are done.
Jim
Great video!!
I'm wiring a fuel tank on a 69 Chevelle, I'm assuming this is similar?
Yes, if you are working on an all original type of system, then it should be the same.
I’m working on a 72 Chevelle trying to address this issue. I’m tired of running out of fuel.
good video..
+Chris Craft I'm glad you liked it. I've helped many with fuel gauge issues and it's nice with something like this to explain things with pictures instead of just words. Jim
how would i trouble shoot the gas guage for a 68 c10
You need to identify the sender wire at the tank or at some connector between the tank and the gauge (or even at the back of the gauge) and then do the basic test with having the ignition switch to the run position and then having the wire to the sender disconnected to see if the gauge reads full or above and then grounding the sender wire which goes towards the gauge to see if it goes to the empty or below mark. I've also found out this test is VERY basic but to confirm the gauge is reading properly is to use different resistors like a 90 ohm, a 67.5 ohm, a 45 ohm, a 22.5 ohm, and some others between the sender wire going to the gauge and to ground to verify it reads about 1/4 full with the 22.5 ohm resistor and then about 1/2 full with the 45 ohm resistor and then about 3/4 full with the 67.5 ohm resistor and about full with the 90 ohm resistor. Most of the gauges have what they call a shunt resistor across the back of the gauge which if bad can throw of the accuracy of the gauge.