Need help with fuel gauge that stop working

UNCbronco · Jun 12, 2019

OK My fuel gauge stop work a while back, So I changed the sending unit in the tank. The old one I took out had seen better days. So I put the new one in and had my fuel gauge back working for about two weeks till today and it stop working again. I took the orange and black wires off the back of the gauge and hook a battery to gauge to check and see if it would read. It goes up to full and I take power off and it will drop back down to empty. So I am thinking the gauge is good. My question to anyone that can help me is what do I check now ? Where does the power come from to make this work ? I am lost to check for something else. Thanks for any help. Keith

rydog1130 · Jun 12, 2019

check your ohms on your sending unit...those brass floats can leak then sink to the bottom of the tank. If your sending unit is reading 73 ohms and you know you have gas in there then your float is bad. I had the same issue... 10 ohms full and 73 ohms empty....grave yard sells a plastic float that doesn't leak....start there first

UNCbronco · Jun 12, 2019

rydog thanks for the help, My buddy borrowed my ohms meter and has not brought it back. So I will have to get it back from him tomorrow and check the ohms. So you think the new sending unit that I bought from Dennis Carpenter is bad ? If that`s the case then the last three parts that I have gotten from them has been bad parts. I live here in NC and I am thinking this is a good business to buy from. I am second guessing myself now. Just saying that the sending unit is still good, what would I check then ? Thanks, Keith

UNCbronco · Jun 12, 2019

Hey rydog, I looked on Graveyard`s website. Are you talking about the 66-89 composite float for $12.00 item number 10223 ? If so, take the sending unit out and replace the brass float with this one here ? Thanks

rydog1130 · Jun 12, 2019

My brand new unit from jeffs crapped out on me too... its just poorly made. I tested like I mentioned above before pulling it to confirm it was the unit and mine was reading empty. I replaced the float with this guy....

https://shop.broncograveyard.com/19...mposite-Sending-Unit-Float/productinfo/10223/

ok, so unit is working fine...wiring next...check your ground and connections. Make sure theyre clean. The ground is usually right on the frame above where the sending unit faces. Clean the prongs on the unit and plugs, check gauge for reading. If that doesn't work check the continuity of your positive lead to your guage, if that's ok then it might be the gauge itself. This part might be bad but if your other gauges are working probably not the case https://shop.broncograveyard.com/1966-1977-Ford-Bronco-Constant-Voltage-Regulator/productinfo/17121/
and link to new guage https://shop.broncograveyard.com/1966-77-Ford-Bronco-Fuel-Gauge/productinfo/17128/

I'm thinking though its your float in the tank....if you cant get you multi meter back HF has them for $8

UNCbronco · Jun 12, 2019

Yes I took the ground a loose and cleaned it on the frame rail . I had put a new fuel gauge in two weeks ago before I changed the sending unit thinking that was my problem. Like I said in my first post I hooked it up to a battery and it went up to full and I took it off the battery and it went back down to empty, so I am thinking it`s still good. right ? All my other gauges in the cluster are working fine. Like you said it all goes back to the sending unit. I will check the olms with a meter tomorrow. Thanks a lot for your help.

rydog1130 · Jun 12, 2019

UNCbronco said:
Hey rydog, I looked on Graveyard`s website. Are you talking about the 66-89 composite float for $12.00 item number 10223 ? If so, take the sending unit out and replace the brass float with this one here ? Thanks

yup that $12 float is what you need...they just pop in and out...super easy

UNCbronco · Jun 13, 2019

Got my meter back this morning and ohms the sending unit out and got 43 ohms on the meter. If that`s right my unit is showing half full of gas in the tank. If you look up sending units on Graveyard`s website under sending units on that listing it shows 10 ohms is full and 80 ohms is empty. So if my unit shows 43 ohms is that half full ? Thanks

.94 OR · Jun 13, 2019

Could be half empty...

DavidDFW · Jun 13, 2019

That was funny

rydog1130 · Jun 13, 2019

you might have a loose connection on the back of your cluster, or your wire from the unit to your gauge has a short. I'm also wondering if you might have damaged your gauge by hooking a battery up to it? Those run off 8 volts hence the little voltage regulator on the back of the cluster. One member to consult would be Kevin from Classy Gauges. He specializes in rebuilding these. You can look him up in the vendor section. His user name is falling down I believe...he might be able to help

UNCbronco · Jun 13, 2019

I hooked up a small 9 volt battery to it to check it. Today I ran a new orange wire from the sending unit to the back of the fuel gauge. I also put a new plug on the sending unit with a new ground wire to the frame above the sending unit. I also check the plugs on the back of the fuel gauge. All this being done still no movement from the fuel hand on the gauge. Man this has been something to get this damn hand to move and tell me how much gas I have in the tank.

rydog1130 · Jun 13, 2019

Last two options A) check your battery make sure its charged, B) check your switch that controls what sending unit is being read ....good luck!

Need help with fuel gauge that stop working

UNCbronco

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rydog1130

Bronco Guru

UNCbronco

Full Member

UNCbronco

Full Member

rydog1130

Bronco Guru

UNCbronco

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rydog1130

Bronco Guru

UNCbronco

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.94 OR

Bronco Guru

DavidDFW

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rydog1130

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UNCbronco

Full Member

rydog1130

Bronco Guru

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