Fuel tank swap

[Hotrod1967]

I’m replacing the fuel tank on my 2003. It had and evap leak when I bought it and after pulling the tank I can see why.
I’ve got another tank to replace it with but after installing it got no response from the fuel pump or sending unit. I think the 2nd tank is from an 05 and has a different pump and connector. Any thoughts on how to get this to work? The 2nd tank is installed right now.
Thanks Scott

 

[Steel City 06]

Have you tried the old pump in the new tank? I don't think the pumps are interchangeable between vehicle years

 

[toximus]

Switch the positive and ground wires to the pump in the wiring harness. Their pin position changed between those years.

There's 4 wires in the harness: 2 smaller 20ga, 2 larger 18ga. The 18ga wires are for the pump.

 

[toximus]

Have you tried the old pump in the new tank?

It's close but unfortunately won't fit.

 

[LukesfirstJeep]

The replacement tank is a later model and the fuel pump is different. I don't know how to make it work. If your old pump fits in the new tank, make sure you "fix" the little check valve in the filler neck. It's a 5 minute job. I think there's a video in the How To section.

 

[Hotrod1967]

Switch the positive and ground wires to the pump in the wiring harness. Their pin position changed between those years.

There's 4 wires in the harness: 2 smaller 20ga, 2 larger 18ga. The 18ga wires are for the pump.

Thanks. This sounds like my best and easiest option. Otherwise I was gonna look for a used 03 tank. The newer one is installed already so I’ll try switching the wires. My harness is for the 03. They are all the same gauge but different colors. Do you know where I could find a diagram?

 

[qslim]

Thanks. This sounds like my best and easiest option. Otherwise I was gonna look for a used 03 tank. The newer one is installed already so I’ll try switching the wires. My harness is for the 03. They are all the same gauge but different colors. Do you know where I could find a diagram?

View attachment 129545

Look the the "Resources" forum, all the TJ FSMs are there for every year. Section 8W for wiring.

 

[toximus]

You don't need the pump side of the connector, only the vehicle side connector. Unless your Jeep was made incorrectly the wires are different sizes.

To fit your vehicle side connector onto the 05-06 pump you'll need to shave the "key" off the connector on the pump. Other than the key it's the same connector.

 

[Hotrod1967]

Thank you. I did shave it down. I’ll try switching the pump wires. Does the sending unit utilize the same ground. This has been great advice. I appreciate it.

 

[toximus]

Thank you. I did shave it down. I’ll try switching the pump wires. Does the sending unit utilize the same ground. This has been great advice. I appreciate it.

The fuel pump and sending unit have different grounds.

 

[Hotrod1967]

The fuel pump and sending unit have different grounds.

Thanks

 

[Hotrod1967]

Coming from the front are the black and green with white line the 2 for the fuel pump? Leaving the blue with green line and black with green line for the sending unit?

 

[Hotrod1967]

If so, the green with white line should be the only powered one correct?

 

[toximus]

Coming from the front are the black and green with white line the 2 for the fuel pump? Leaving the blue with green line and black with green line for the sending unit?

Correct.

 

[Hotrod1967]

Fuel tank swap update.
The 2005 fuel tank is installed in my 03. Everything is reconnected. I’ve got no response from the pump or gauge. When I first tried it I had the wires set up like the 03. Then after the reply’s I slipped the 2 larger wires and still nothing. Would it blow a fuse or anything from my initial starting attempts? The pump and tank are used but look to be in good shape.is there a factory pump kill switch that needs reactivated. Any thoughts are welcome.

 

[toximus]

Fuel tank swap update.
The 2005 fuel tank is installed in my 03. Everything is reconnected. I’ve got no response from the pump or gauge. When I first tried it I had the wires set up like the 03. Then after the reply’s I slipped the 2 larger wires and still nothing. Would it blow a fuse or anything from my initial starting attempts? The pump and tank are used but look to be in good shape.is there a factory pump kill switch that needs reactivated. Any thoughts are welcome.

Did the pump work before the swap?

 

[Hotrod1967]

Did the pump work before the swap?

The original one from my 03 tank ran fine. I don’t know about the one in the 05 tank. It looked in good shape but I didn’t test it before swapping the tank.

 

[Hotrod1967]

This is the new one.

 

[toximus]

Check the fuel pump fuse under the hood. If the fuse is fine, test the connector with a test light or multimeter. There should be power to the pump for a few seconds when turning the key to the on position.

 

[Hotrod1967]

Will do. Thx