Sending Unit/Fuel gauge

[minifridge1138]

Hey everyone,

I won't bore you with details, but I have to switch from the stock electric fuel pump to a mechanical fuel pump. (I really don't have much choice, please don't tell me all the reasons this is a bad idea. you'll only depress me).

I am thinking of switching to a 1981 fuel tank sending unit. The only thing i haven't worked out is the fuel gauge. I still have the stock sending unit and the gauge works perfectly.

If i switch to an 1981 sending unit, what will i need to do to make sure the fuel gauge still works? Other than plumbing to accommodate the in-tank pump, i'm not sure what changed from 81 to 82.

Any thoughts/suggestions/tips are VERY appreciated.
Thank you!

 

[wishuwerehere82]

I don't think you need to remove the 82 sending unit. Just extend the fuel pickup hose to bypass where the pump was taken out. It should work just fine using the original sending unit and fuel lines with a mechanical pump.
You have too much presure with the electric pump to work with a carb setup.

 

[minifridge1138]

hmm.....
I hadn't really thought about extending the hose.

I thought the hose terminated outside the tank by connecting to some metal tubing. Then the metal tubing runs to the fuel pump and the fuel pump sucks in fuel.

I didn't think the fuel line ran INTO the tank. Just TO the tank.

 

[wishuwerehere82]

The fuel line connects to the filler neck at the same flange as the sender connector. If you pull out the sender unit, the pump is right there on thr same metal bracket. All you need to do is take out the pump, and put a section of rubber hose between the pickup sock and the metal tube that the fuel pump was on. That's it!

And you might want to connect the 2 fuel pump wires together to ensure that in the future there is no chance of someone plugging in the fuel pump connector and blowing themselves up.

 

[Hib Halverson]

Hey everyone,

I won't bore you with details, but I have to switch from the stock electric fuel pump to a mechanical fuel pump. (I really don't have much choice, please don't tell me all the reasons this is a bad idea. you'll only depress me).

I am thinking of switching to a 1981 fuel tank sending unit. The only thing i haven't worked out is the fuel gauge. I still have the stock sending unit and the gauge works perfectly.

If i switch to an 1981 sending unit, what will i need to do to make sure the fuel gauge still works? Other than plumbing to accommodate the in-tank pump, i'm not sure what changed from 81 to 82.

Any thoughts/suggestions/tips are VERY appreciated.
Thank you!

If that 82 is still equipped with electronic fuel inection, the engine is unlikely to run properly with a mechanical pump because most O.E. type, engine-driven pumps cannot supply adequate pressure for the EFI to run right.

 

[wishuwerehere82]

If that 82 is still equipped with electronic fuel inection, the engine is unlikely to run properly with a mechanical pump because most O.E. type, engine-driven pumps cannot supply adequate pressure for the EFI to run right.

It's not. He is running a 600 CFM Holley carb.

 

[minifridge1138]

Yeah, i've got a carb.

Don't blame me.
The previous owner(s) removed the crossfire.
I bought the car because I always liked the C3 and it was a good price.
The car ran, but needed some work. Frame and body were straight. The interior only had minor wear and tear (as expected on a 25 year old car).

The upside is that carburetors are easy to adjust and there are no longer any sensors or computers in the car.
The downside is that i get to fix a lot of things the previous guy did wrong.

The reason i started this thread is that the previous owner put in the carb and a mechanical fuel pump. BUT he left the electrical one in the tank and killed the power to it. He then hooked the mechanical fuel pump to the return line to the tank. There are several problems with this. The main one being that the fuel return doesn't go to the bottom of the tank so I am out of gas when the gauge reads 1/4.
I'm also using a fuel line that is smaller in diameter.

I always wanted an old car that I could "play" with. Be careful what you ask for.

Thanks!