Install aftermarket fuel gauge?

insidegroove

Member
Joined
Jul 14, 2022
Messages
19
Reaction score
13
Location
01550
I'm ordering a new sending unit for my 1969 Roadrunner. My factory fuel gauge is still giving me fits even though ive gotten every other gauge and dash light working. my question is, has anyone ever just installed an aftermarket stand alone fuel gauge on the bottom of their dash? can i buy one and just wire in that one direct and just ignore the factory one up in the dash? would i have to buy a particular gauge or would any work since im starting new?
 

Russ69Runner

Well-Known Member
Joined
Aug 4, 2016
Messages
7,155
Reaction score
2,625
Location
Lake Wales Fl.
Your original gauge should work fine. Don't know why you are having a problem with it. But I did have a guy go through my dash cluster for me. He checked and cleaned everything. Don't know if they sell that fuel gauge for non-rally cluster. If that is what you have.
 

Rumrunner

Well-Known Member
Joined
Mar 27, 2019
Messages
97
Reaction score
69
Location
Manteca CA
I've been doing a nuts and bolt restoration for three years now. Of course I have a life to fill the gaps.
My fuel gauge has never worked. First thing I did was get a new fuel sending unit, nothing. Had other problems and didn't work on this but from time to time. I have spent about fourteen hours (beer breaks) with separate car friends for the last three days just on this problem
I believe the gauge works because I attach a wire from the battery ground to the connector behind the driver kick panel where the schematic says to the fuel gauge and the gauge slowly goes to full. (help me if this is wrong). I checked continuity form wire that attached to the fuel sending unit ot it's other end behind the kick panel and that's good. I checked the new sending unit and the ohms change when i move the float that attaches to the rheostat and that's working.

When I hook it all up,,,nothing!

69 Hemi stated that the ohms from the fuel gauge and the sending unit have to match. Huh?
Russ, I did clean the back of the gauge cluster when It was out. (don't remember how)

Even though I believe the sending unit (along with the original that I threw away) work, I ordered a new one that has not arrived but didn't see anything about ohms when I ordered it. (Maybe didn't look close enough)

What are the ohms for these supposed to be? How do I check the ohms on the fuel gauge? As far as I can tell the ohms on the sending unit change depending where the float is.

This problem has been a issue since I got this car but after this week I am lost.
Help!
 

69hemibeep

Sponge Bob Square Wheels
Joined
Sep 10, 2008
Messages
21,896
Reaction score
1,955
Location
AZ Desert,
I was talking about an stand alone aftermarket gauge. I would check the wire from the kick panel to the tank next
 

V.R.D

Well-Known Member
Joined
Oct 27, 2020
Messages
287
Reaction score
324
Location
florida
zero empty and 70 ohms full. i have had 2 new send units and neither worked with my gage but i have a digital dash but back in the day i would take apart the rheostat and clean it with 1000 grit sand paper and test with meter and got them to work these new sending units are not wound the same as factory . if you could find a old one it would clean up and work. test your new one buy hooking up the blue [ i think ] to the unit and ground the sending unit and mock it moving to see if you can get a reading.
 

Rumrunner

Well-Known Member
Joined
Mar 27, 2019
Messages
97
Reaction score
69
Location
Manteca CA
Thanks for your quick responses.

I've check the continuity each time I approach this issue and it is good.

Just now checked the ohms on the sending unit. Low was 9 and high was 76.
1,000 grit sand paper a few times and low is now .3 and high is 75 so it did make a difference.
Of course I threw the old one away about two and a half years ago.
I don't know what you mean by hooking up the blue?
 

V.R.D

Well-Known Member
Joined
Oct 27, 2020
Messages
287
Reaction score
324
Location
florida
the wire to the fuel tank is blue look at the wiring diagram
 
Top