I have nearly zero mechanical knowledge, you probably figured that out by the post title. Can anyone tell me what the wiring inside the rear bumper and towards the top of the gas tank is? When I bought the car I was told the connection can be dicey on hot days. I just got stranded, tried jumping it, then remembered about this wiring, so I got under there, jiggled it around and the car started right up. I need to replace this thing, seems like a simple enough fix, let me know your thoughts.
Wire Behind Gas Tank
- Thread starter Eman1019
- Start date
-
Sponsors (?)
Drop the tank, if it has a lot of miles plan a fuel pump install, pretty easy, things you will need, fuel pump (duh), the rubber gasket for the fill pipe, fuel filter, be sure to pay attention to the plug and wires that go to the fuel pump, they can turn black from bad connections, poor installation, drain as much gas as you can, I will summon @jrichker, he has an excellent procedure for draining the tank that is almost effortless.
Here are some useful tips...
I have done the tank removal three times, and the main issues are getting the car up on jack stands and getting the gas out of the tank. DO NOT try to do this job without jack stands. Becoming a pancake is not part of the repair process.
Pumping out the old gas:
If the old pump still works, you can use it to pump the tank out.
1.) Separate the pressure line (the one with the Schrader valve on it) using the fuel line tools.
Look in the A/C repair section for the fuel line tools. They look like little plastic top hats. You will need the 1/2" & 5/8" ones. The hat shaped section goes on facing the large part of the coupling. Then you press hard on the brim until it forces the sleeve into the coupling and releases the spring. You may need someone to pull on the line while you press on the coupling.
OR
View: https://www.youtube.com/watch?v=vRTjYAxvaCs
Use a piece of garden hose to run from the pressure line to your bucket or gas can. Make sure it is as leak proof as you can make it. Fire and explosion are not part of the repair process...
2.) Jumper the fuel pump test point to ground.
Turn the ignition switch to the Run position. the fuel pump will pump the tank almost dry unless the battery runs down first.
Some 5 gallon paint pails lined with garbage bags are good to hold the gas. The garbage bags provide a clean liner for the pails and keep the loose trash out of the gas so you can reuse it. If you decide to use a siphon, a piece of 1/2" garden hose stuck down the filler neck will siphon all but a gallon or so of the gas.
Remove the filler neck bolts and put them in a zip bag. Disconnect the supply & return lines by removing the plastic clips from the metal tubing. If you damage the clips, you can get new ones form the auto part store for just a few dollars. I have used tie-wraps, but that is not the best choice. Then you remove the two 9/16" nuts that hold the T bolts to the straps. Put the nuts in the zip bag with the filler bolts. Pull the plastic shield down and away from the tank. Once the tank drops a little bit you can disconnect the wiring for the pump & fuel quantity sender.
The pump assembly comes out by removing a large metal ring that unscrews from the tank. You are supposed to use a brass punch to tap on the ring so that you don't make sparks. Look closely at the rubber O ring gasket when you remove the sender: it is very easy to damage on reinstallation. If it gets damaged, the car will smell like gasoline when you fill the tank up. The pump assembly requires some twisting and turning to get it out the hole.
Look very closely at the electrical wiring. The stock fuel pump wiring can overheat and melt the insulation. Mine had some really crummy plastic tubing slid over the quick disconnects. If the wires ever got together, there would be sparks inside the fuel tank and no more Mustang. I eliminated the splice in the middle of the wiring and went straight from the pump to the feed through connectors for the wiring. It required some soldering and crimping of new tabs on the wires, but it made a neater job.
Inspect the pump mount to metal tubing bracket. Mine broke and I couldn't get it to solder back together. I drilled a small hole for a machine screw & self locking nut to hold the clamp and bracket together.
The pump is easy to get off the mount but is somewhat difficult to get back it the tank without damaging the sock filter or tearing it on the tank baffle. When you install the metal ring that holds the pump in place, watch out for the gasket O ring. Some RTV may be helpful if the ring is not in excellent condition.
The tank to filler pipe seal is a large rubber grommet. Inspect it for hardening, tears and damage. At $20 from the Ford dealer, it might be a good idea to replace it.
I used a floor jack to help lift the tank back in place. A piece of ¾” plywood cut to about the same size as the tank will help insure that you don’t damage the tank by using the floor jack to lift it in place. You may find that it is the only time you really can make good use of a helper.
I have done the tank removal three times, and the main issues are getting the car up on jack stands and getting the gas out of the tank. DO NOT try to do this job without jack stands. Becoming a pancake is not part of the repair process.
Pumping out the old gas:
If the old pump still works, you can use it to pump the tank out.
1.) Separate the pressure line (the one with the Schrader valve on it) using the fuel line tools.
Look in the A/C repair section for the fuel line tools. They look like little plastic top hats. You will need the 1/2" & 5/8" ones. The hat shaped section goes on facing the large part of the coupling. Then you press hard on the brim until it forces the sleeve into the coupling and releases the spring. You may need someone to pull on the line while you press on the coupling.
OR
View: https://www.youtube.com/watch?v=vRTjYAxvaCs
Use a piece of garden hose to run from the pressure line to your bucket or gas can. Make sure it is as leak proof as you can make it. Fire and explosion are not part of the repair process...
2.) Jumper the fuel pump test point to ground.
Turn the ignition switch to the Run position. the fuel pump will pump the tank almost dry unless the battery runs down first.
Some 5 gallon paint pails lined with garbage bags are good to hold the gas. The garbage bags provide a clean liner for the pails and keep the loose trash out of the gas so you can reuse it. If you decide to use a siphon, a piece of 1/2" garden hose stuck down the filler neck will siphon all but a gallon or so of the gas.
Remove the filler neck bolts and put them in a zip bag. Disconnect the supply & return lines by removing the plastic clips from the metal tubing. If you damage the clips, you can get new ones form the auto part store for just a few dollars. I have used tie-wraps, but that is not the best choice. Then you remove the two 9/16" nuts that hold the T bolts to the straps. Put the nuts in the zip bag with the filler bolts. Pull the plastic shield down and away from the tank. Once the tank drops a little bit you can disconnect the wiring for the pump & fuel quantity sender.
The pump assembly comes out by removing a large metal ring that unscrews from the tank. You are supposed to use a brass punch to tap on the ring so that you don't make sparks. Look closely at the rubber O ring gasket when you remove the sender: it is very easy to damage on reinstallation. If it gets damaged, the car will smell like gasoline when you fill the tank up. The pump assembly requires some twisting and turning to get it out the hole.
Look very closely at the electrical wiring. The stock fuel pump wiring can overheat and melt the insulation. Mine had some really crummy plastic tubing slid over the quick disconnects. If the wires ever got together, there would be sparks inside the fuel tank and no more Mustang. I eliminated the splice in the middle of the wiring and went straight from the pump to the feed through connectors for the wiring. It required some soldering and crimping of new tabs on the wires, but it made a neater job.
Inspect the pump mount to metal tubing bracket. Mine broke and I couldn't get it to solder back together. I drilled a small hole for a machine screw & self locking nut to hold the clamp and bracket together.
The pump is easy to get off the mount but is somewhat difficult to get back it the tank without damaging the sock filter or tearing it on the tank baffle. When you install the metal ring that holds the pump in place, watch out for the gasket O ring. Some RTV may be helpful if the ring is not in excellent condition.
The tank to filler pipe seal is a large rubber grommet. Inspect it for hardening, tears and damage. At $20 from the Ford dealer, it might be a good idea to replace it.
I used a floor jack to help lift the tank back in place. A piece of ¾” plywood cut to about the same size as the tank will help insure that you don’t damage the tank by using the floor jack to lift it in place. You may find that it is the only time you really can make good use of a helper.
It's not that hard, you can swing this one.
Hardest part will be putting the tank back in. They can be a little btchy.
Hardest part will be putting the tank back in. They can be a little btchy.
These foxbody Mustangs are cars for enthusiasts. guys and gals who have mechanical skills and aren't afraid to jump in and do things. There are a lot of things that need attention either due to age, mileage or previous owner's attempts to modify the car.If you are going to keep the car, learn how to work on it. You will need tools, a place to work on the car and at least a Chilton shop manual for your year car. Stangnet is one of the best places to get help if you get stuck or want some troubleshooting assistance.
If you aren't up to this, I suggest that you sell the car and buy something else. Otherwise, there will be a constant stream of little things that cost $$$, the mechanic will have a chokehold on your wallet and you will grow to hate the car.
Last edited:
This is a great chance to really learn how to do it. Assuming this is not a everyday car and just a weekend cruiser, run it till it's almost out of gas, put it on jacks stands and get it done. You'll be glad you did it.
I'm not afraid to try things on my own, I'm looking to replace the throttle body myself, just don't have a comfort level with the gas tank as the prior owner did some work on it and i got stuck on the side of the road due to his shoddy work.
If you can change a tire you can do the gas tank. There is no better feeling than a job you did yourself, even if it poops out because you did something wrong or didn't resolve the issue at hand you can say 'I screwed it up all by myself and didn't need anybody to help me'.
Now get after it.
No, really, it's rolling down the driveway, you didn't set the parking brake.
Now get after it.
No, really, it's rolling down the driveway, you didn't set the parking brake.
What really helps many of us, I know especially myself included, is to have been lucky to begin early (like 12 years old, or less) working with, experimenting with, trying ideas, failing, trying again, learning, gaining experience, mentally verifying failures so as to not repeat mistakes.....
Electrical
I learned from Lionel Trains. My folks were astute, saw my intense interest, bought me stuff of technical value. At 14, I dropped the oil pan of my old man's '55 Merc Transmission, and disassembled the Valve Body. Barely lived through that one! But re-assembled, it worked! (Thank God!).
Now, a "pencil-pusher" reaching 30, or 40, experiencing problems with his vehicle, has passed through those very important early-years unexposed to the Maelstrom of Trouble. He is understandably lost, has heard the everyday "jargon", uses it, which misleads us gearheads, and we bury him with EFI "PIPS", "SPOUT", etc.
Those are the guys I would like to help. imp
Electrical
I learned from Lionel Trains. My folks were astute, saw my intense interest, bought me stuff of technical value. At 14, I dropped the oil pan of my old man's '55 Merc Transmission, and disassembled the Valve Body. Barely lived through that one! But re-assembled, it worked! (Thank God!).Now, a "pencil-pusher" reaching 30, or 40, experiencing problems with his vehicle, has passed through those very important early-years unexposed to the Maelstrom of Trouble. He is understandably lost, has heard the everyday "jargon", uses it, which misleads us gearheads, and we bury him with EFI "PIPS", "SPOUT", etc.
Those are the guys I would like to help. imp
That's me, I didn't have the early years of experience, just getting into it at 44.What really helps many of us, I know especially myself included, is to have been lucky to begin early (like 12 years old, or less) working with, experimenting with, trying ideas, failing, trying again, learning, gaining experience, mentally verifying failures so as to not repeat mistakes.....
Electrical
Now, a "pencil-pusher" reaching 30, or 40, experiencing problems with his vehicle, has passed through those very important early-years unexposed to the Maelstrom of Trouble. He is understandably lost, has heard the everyday "jargon", uses it, which misleads us gearheads, and we bury him with EFI "PIPS", "SPOUT", etc.
Those are the guys I would like to help. imp
@Eman1019
I understand that. What counts in your favor is an ability to think things through, view the problem at hand, then devise ways to approach it if you haven't encountered anything like it before.
Part of this depends strongly on your personal background, your experiences of a technical nature. If your academic career was based on non-technical curriculum, such as Social Sciences, you are at a decided disadvantage, sorry to say. However, OTOH, if you showed interest early on for some of the things which drove many of us to fanatic desire to understand WHY they designed it this way, WHY it works this way, WHAT makes it work this way, there is no reason why you cannot start picking it up at 44. Never to old to learn. I learn something everyday at 75. Some of it is useless, but not all. If we can help, we will. imp
And, you really can do this. It just seems intimidating is all.
After you do it, you'll think "that wasn't so hard at all".
After you do it, you'll think "that wasn't so hard at all".
I have tackled things on my car and my truck too that in the past I have paid others to do, I do have a close friend with a auto repair shop that has done my work in the past, this is what he's told me,
'You can do it and when you screw it up I can charge you a butt load of money to fix it right'
'You can do it and when you screw it up I can charge you a butt load of money to fix it right'
- Jul 12, 2017
- 2,408
- 1,381
- 173
I just replaced that harness your talking about. Sending unit and fuel pump harness. The plug to my sending unit was dry rotted and in a million pieces. I was able to find a used one, I heard bad things about new aftermarket. Dropping the tank, replacing the fuel pump, sending unit, and all new seals took about 2-1/2 hours. Really not that bad. Take everyones advice and try to do it yourself. Its really not that hard.
Similar threads
