Fuel Tank Sending Unit Plug

fatweasel · **Posted:** Wed Oct 04, 2017 8:33 pm

Does anyone know if the plug on the existing OE wire harness is compatible with a fuel pump/sender unit?

My sender has failed and I figure if I am going to drop the tank might as well install a unit with a fuel pump - like a CARTER-P76148M.

I realize that the current harness only has 2 wires for the OEM level sender. Was wondering if I can add the 2 additional wires, for the fuel pump power and ground, to the existing plug or do I need a new plug with 4 wires?

dh100m · **Posted:** Wed Oct 04, 2017 8:46 pm

no best way is to get one from a gas 3.7 libby it is easy to change over a few wires in the plug socket and your good to go
there is a very good thread on this site google it and you should find it I cut an access hole in the floor instead of removing tank
So any future trouble is easy to get at
best of luck

GordnadoCRD · **Posted:** Wed Oct 04, 2017 8:47 pm

fatweasel wrote:

Does anyone know if the plug on the existing OE wire harness is compatible with a fuel pump/sender unit?

My sender has failed and I figure if I am going to drop the tank might as well install a unit with a fuel pump - like a CARTER-P76148M.

I realize that the current harness only has 2 wires for the OEM level sender. Was wondering if I can add the 2 additional wires, for the fuel pump power and ground, to the existing plug or do I need a new plug with 4 wires?

Every sending unit body that I've seen, with pump or without, uses the same 4 wire plug. This includes the wrecking yard ones from 3/4 and 1 ton diesels, and even gas models. The only differences I've found are the sending unit float arm, which is easily switched with yours, and the 'tab' from the outside ring, which isn't strictly needed anyway... as long as the fittings face directly forwards, or directly backwards. Either works if you replace the stupid plastic tab-lock junk that connects the tank to the steel lines.

{EDIT} Unless you're comfortable with making the necessary wiring loom modifications yourself, you should get the pre-fabbed wiring loom from Sasquatch parts. It's plug and play, no worries, no hassles, and doesn't have the old insulation issues that oem wiring can have.
Don't worry about dropping the tank, as long as you have all the fuel pulled out. It's way easier than it seems when you think about it but haven't done it before.

WWDiesel · **Posted:** Wed Oct 04, 2017 8:57 pm

fatweasel wrote:

Does anyone know if the plug on the existing OE wire harness is compatible with a fuel pump/sender unit?

My sender has failed and I figure if I am going to drop the tank might as well install a unit with a fuel pump - like a CARTER-P76148M.

I realize that the current harness only has 2 wires for the OEM level sender. Was wondering if I can add the 2 additional wires, for the fuel pump power and ground, to the existing plug or do I need a new plug with 4 wires?

The Carter unit is a good Pump!
The two wires can be added to the plug at the tank end and one wire to the connector under the rear seat if you you have the correct wire ends.
Wire can be resourced from most any parts store.

I did this to mine way back before whole wiring harnesses were available like the ones from Sasquatch Parts.
Only one male connector wire is required at the connector under the rear seat as the other one is simply attached to a ground bolt on the body at that location.
You will need two female ends for the connector the plugs into the top of the fuel pump module.
I would get a few spares of both just in case you mess one up; they are cheap!
After I crimped the wires to the ends, I soldered them for extra insurance of a good long term connection.

The correct APEX wire ends both seem to still be available from Mouser.

This is what I used back in 2013:
Wire Terminals: APEX 2.8MM
male, 14-16 gauge wire, part no> 649-54001441
> http://www.mouser.com/Connectors/Automo ... 41&FS=True

female, 14-16 gauge wire, part no> 649-54001403RWC
alternate part no. with tin plating instead of gold > 10762803-L
> http://www.mouser.com/Search/Refine.asp ... d=54001403

APC9199 · **Posted:** Wed Oct 04, 2017 9:29 pm

I also cut a hole in the rear floor to access the top of the tank...but BE CAUTIOUS if you go this route. The fuel tank sits flush with the bottom side of the sheet metal that you will be cutting through. If you go too deep you will puncture the tank and have to repair or replace it and also deal with whatever slag you inadvertently flung into the tank with your cutting tool. A sparkless cutting tool with a depth stop is the best way to accomplish this. Even though I highly recommend doing it this way, you have to be extremely careful doing it. The added headache of doing this actually saved my butt once when one of the pins in the connector to the in-tank pump vibrated loose and the CP3 didn't have enough draw to pull through the in-tank unit. In less than 10 minutes I had figured out that it wasn't a fuse/relay problem, had the back "hatch" opened up, wire re-inserted, hatch closed and was on my way. Try doing that when you have to drop the tank while parked on the side of the road to find the problem!

WWDiesel · **Posted:** Thu Oct 05, 2017 9:38 am

APC9199 wrote:

I also cut a hole in the rear floor to access the top of the tank...but BE CAUTIOUS if you go this route. The fuel tank sits flush with the bottom side of the sheet metal that you will be cutting through. If you go too deep you will puncture the tank and have to repair or replace it and also deal with whatever slag you inadvertently flung into the tank with your cutting tool. A sparkless cutting tool with a depth stop is the best way to accomplish this. Even though I highly recommend doing it this way, you have to be extremely careful doing it. The added headache of doing this actually saved my butt once when one of the pins in the connector to the in-tank pump vibrated loose and the CP3 didn't have enough draw to pull through the in-tank unit. In less than 10 minutes I had figured out that it wasn't a fuse/relay problem, had the back "hatch" opened up, wire re-inserted, hatch closed and was on my way. Try doing that when you have to drop the tank while parked on the side of the road to find the problem!

Wouldn't it be so nice if they had of just put a bolt on access plate/door for the fuel tank module from the factory! Would make things so much easier!!! :roll:

69Hcode · **Posted:** Sun Oct 15, 2017 8:53 pm

I don't understand cutting a hole in floor when these tanks are so easy to pull!

WWDiesel · **Posted:** Mon Oct 16, 2017 12:39 pm

69Hcode wrote:

I don't understand cutting a hole in floor when these tanks are so easy to pull!

I agree; if you run it until the tank is almost empty (1 gallon or less), dropping the tank is real easy! :wink:

But again, it would be real nice if they had put a bolt on access plate from the factory! :roll:

papaindigo · **Posted:** Mon Oct 16, 2017 2:01 pm

Actually it would have been nice if DCJ had not REMOVED the access panel from the rear deck. IIRC it was there up through the 04 model year.

WWDiesel · **Posted:** Mon Oct 16, 2017 2:20 pm

papaindigo wrote:

Actually it would have been nice if DCJ had not REMOVED the access panel from the rear deck. IIRC it was there up through the 04 model year.

Dang, and to think they only saved probably 3 or 4 bolts! :banghead:

taroo · **Joined:** Sun Apr 27, 2008 2:14 pm **Posts:** 271

69Hcode wrote:

I don't understand cutting a hole in floor when these tanks are so easy to pull!

Yeah. This entire project is easy. You do need to source the connector male and female pins so you can add the hot and ground to the pump. All is well documented on this site. I think they come in a box of ten of each type. Here is what I ordered:

1 x FCI, Apex 2.8 MM Unsealed Series, Female Pigtail, 54001800 (411257) = $8.00
1 x FCI, Apex 2.8 MM Unsealed Series, Male Pigtail, 54001801 (411258) = $8.00

I got them at https://www.midwestconnectorsupply.com

Fuel Tank Sending Unit Plug

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