Fuel tank sender type

[JSenseney]

Greetings again from ‘72 Monte Carlo novice. There’s been a bit of talk about the fuel sending unit possibly causing the meter to peg.

I want to preorder the fuel sending unit from SS396, but would like verification on which.

I do not want to drop the tank just yet, so I crawled under the car and took a photo.

On the picture shown here… two lines going above the fuel tank from front of car. i’m guessing this is the dual pipe version?  Based on your guys Monte intelligence… is this the dual?

Thanks again to all. 

Edited June 23 by JSenseney
additional information

[cny first gen 71]

It does look like it from that angle,  have you checked the ground yet? That's the first thing to check.

[Dtret]

Agreed. Double check all the wiring and the gauge first. 

[Rob Peters]

When you say the gauge is "pegged", do you have a picture of the gauge?  Either a photo or if looking at the gauge as a clock face where is the gauge needle pointing.

rob

[JSenseney]

Thank you, Rob. Attached is the gas gauge photo. I should add, the clock also is not working, but temperature gauge is. 

[72 Monte Carlo]

James,

I think you have more of a bad connection/ wiring issue with the fuel gauge fully pegged at the 3 o'clock position. 

[JSenseney]

Let me look at it from that angle. When I had dash off to replace speakers, i noticed on that circuit board film… that someone had soldered an extra ground lead on for a gauge near speaker. I will take dashboard off again and mirror look at all.

Do you know if these circuit board films being reproduced? 

[GRAY 70 Monte Carlo]

Many sites are reproducing the print circuit boards

[72 Monte Carlo]

James,

I got my circuit board from OPGI, but other sites will have them as well.

You should be able to test the fuel gauge wires with an ohm meter to test continuity for both the positive and negative wires.

[Rob Peters]

James,

With the needle pointing to the 3:00 O'Clock is an indication of an open someplace between the fuel sender unit and and the gauge.  

Find the tan wire in the trunk (The wire is just to the left of the trunk latch as you are looking into the trunk.  It will have a plug connection.  Try disconnecting that plug connection.  Then take a wire and connect one end to a GOOD ground in the trunk and take the other end of  of that wire and connect it securely to the wire going to the front of the car to the  dash.  Then turn he key on and watch the gas gauge. With that wire going to the front is attached to a good ground the gas gauge should read EMPTY.

rob

[Dtret]

Do the investigation of the fuel gauge by the above suggestions but don’t let the clock be an indication of bigger issues. The clock itself is wired to an always hot circuit but in most circumstances they don’t work anyway. The clock motors go bad and are usually gummed up. 

[Scott S.]

The clock is always right twice a day.... Mine's at 2:31.   

[72 Monte Carlo]

1 hour ago, Scott S. said:

The clock is always right twice a day.... Mine's at 2:31.   

Now that's funny 🤣

[DragCat]

11 hours ago, JSenseney said:

Thank you, Rob. Attached is the gas gauge photo. I should add, the clock also is not working, but temperature gauge is. 

Gauge pegged is usually a ground issue........

[cny first gen 71]

3 hours ago, Scott S. said:

The clock is always right twice a day.... Mine's at 2:31.   

Mine is at 5 o'clock it's always time for a beer 🍺 

[JSenseney]

On 6/25/2025 at 12:23 PM, Rob Peters said:

James,

With the needle pointing to the 3:00 O'Clock is an indication of an open someplace between the fuel sender unit and and the gauge.  

Find the tan wire in the trunk (The wire is just to the left of the trunk latch as you are looking into the trunk.  It will have a plug connection.  Try disconnecting that plug connection.  Then take a wire and connect one end to a GOOD ground in the trunk and take the other end of  of that wire and connect it securely to the wire going to the front of the car to the  dash.  Then turn he key on and watch the gas gauge. With that wire going to the front is attached to a good ground the gas gauge should read EMPTY.

rob

Thank you, Rob and others.  
In my case, Rob’s step by step is exactly what happened. Gauge went to empty.

So am I to think now, that it is the sending unit and/or to look at wire going to sending unit and check it? 

(I had to remove dash again for speaker related fix, so I checked for ground at the fuel gauge post and it had ground present)  

[cny first gen 71]

I assume you did check the ground wire from sending unit to the body where it attaches to the body?

[JSenseney]

I have not yet. That’s next. 

I was also able to research my answer on what’s next a bit further by using the search feature on the website.  

Thanks for the assist.

[Dtret]

On the top of the tank there is a wire attached to the sender, that wire lays on top of the tank. The other end just gets screwed to the body, passenger side close to the middle of the car. If it’s still connected take it off clean the end and the body and reattach. Rust plays havoc on that one. 

[Rob Peters]

1 hour ago, Dtret said:

On the top of the tank there is a wire attached to the sender, that wire lays on top of the tank. The other end just gets screwed to the body, passenger side close to the middle of the car. If it’s still connected take it off clean the end and the body and reattach. Rust plays havoc on that one. 

That ground wire on my 70 was and still is screwed to the body on the drivers side.  It is screwed to directly to the gas tank strap mounting bracket.  That ground wire is soldered to a blade on the sending unit.  The tan wire that goes into the trunk just snaps onto a pin on the sending unit.  I guess where the ground wire attaches to the car body doesn't really matter as long as it is a good clean mounting connection.

rob

[Dtret]

41 minutes ago, Rob Peters said:

That ground wire on my 70 was and still is screwed to the body on the drivers side.  It is screwed to directly to the gas tank strap mounting bracket.  That ground wire is soldered to a blade on the sending unit.  The tan wire that goes into the trunk just snaps onto a pin on the sending unit.  I guess where the ground wire attaches to the car body doesn't really matter as long as it is a good clean mounting connection.

rob

Thanks Sir. 

[Leghome]

1 hour ago, Dtret said:

Thanks Sir. 

ROFLMAO

[Rob Peters]

4 hours ago, Dtret said:

On the top of the tank there is a wire attached to the sender, that wire lays on top of the tank. The other end just gets screwed to the body, passenger side close to the middle of the car. If it’s still connected take it off clean the end and the body and reattach. Rust plays havoc on that one. 

 

Is possible that different assembly plants and maybe even assembly lines within  the same plant may have attached that ground wire differently and dare I say deviated from the assembly manual?

rob

[Dtret]

8 hours ago, Rob Peters said:

 

Is possible that different assembly plants and maybe even assembly lines within  the same plant may have attached that ground wire differently and dare I say deviated from the assembly manual?

rob

That would never happen. lol. Rules are rules. 😝

[JSenseney]

Update to my Fuel Gauge problem (pegged at 3 o’clock position)

It was the Fuel Sender. 

Starting again with a big thanks to all of you for your helping answers.

Emptied tank, marked all 5 lines from tank, dropped tank.  While tank down, i treated the metal under and around the tank with Ospho and then Eastwood rust encapsulator. New hoses. 

Installed Dorman 692-244 Fuel Sender. 
Gas Tank reinstalled. Pain dealing with old compression clamps and new hose thickness. 

Refilled tank…. Checked gauge…. YES!!! we have a gauge. 

So if you’ve read this far…. one more simple question. While on creeper and rolled under differential, I noticed these 4 lines.  Assume fuel.  Didn’t see clamps on these. Are clamps necessary?