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Hi, I'm Mike from 1A Auto. I hope this how-to video helps you out, and next time you need parts for your vehicle, think of 1AAuto.com. Thanks.
In this video, we're going to show you how to replace the fuel pump and sending unit on this 2003 GMC Envoy XL. It's the same part and similar process on a variety of these Envoys, from 2002 to 2004. You can view the parts page on our website, and there's a list of the vehicles it fits. The items you'll need for this is a new fuel pump and sending unit module from 1AAuto.com, 7mm and 15mm socket and ratchet, 11mm wrench, flat blade screwdriver, pliers, drip pan, hammer and a chisel, pick, paper towels, jack and jack stands, and depending on the condition of your fuel tank straps you may also need a reciprocating saw.
Start out by locating the relay for your fuel pump and there's a fuse box under the hood right behind the battery. Ours is number 41, which is that one there. Start up the vehicle and then pull that fuse relay. Eventually the engine will cut out as it loses fuel. Then put the relay back in after you have turned off the key. You can put the relay back in. Make sure you don't turn the key on again. That will re-pressurize the system.
Now you can take off underneath in front of the fuel tank, this is the drain for the fuel. We're just going to use a screwdriver, take the cap off and press in the valve. That will allow the fuel to drain and we have a drip pan underneath to catch it.
The next step will be to disconnect the fuel lines. You push in on the fuel lines and then there is basically a clip that you press the ears, you can see it better on this on. I use the pliers to press the ears in on the clip, and then you should be able to pull the fuel line off. Some of them come off easier than others. You'll want to disconnect three fuel lines in total. The one coming from the front to the fuel filter, and then the two up top here. There are flat spots at the top and bottom of this. Push the fuel line trying to get it loosened up.
Now at the back of the vehicle you just want to loosen up this hose clamp on the fuel filler neck. Now pull that hose tube from the filler neck. It takes a little bit of force. Also, you want to check the condition of your filler neck. At 1A Auto we also sell new filler necks. If yours is rusted or anything like that, it may be time to replace it.
Now just lift up on the tab and disconnect that harness. Then you want to remove these four 15mm bolts on this crossbar. We'll fast forward as Mike does that and pulls that crossbar down. You can use a socket and ratchet, but we're going to use some air powered tools to speed it up.
Now there's a 15mm bolt on each gas tank strap. You want to go ahead and remove those. It does help to remove them if you add some penetrating oil. Then we'll just go ahead and remove those. Now, with this one, we had some problems. We couldn't actually get the bolt to come out. We ended up breaking off up in there, so we're going to use a reciprocating saw to just cut it. You want to be careful not to cut the tank. Be careful not to cut anything but that bolt. If this doesn't work or you don't have a reciprocating saw, you can also use an air hammer and just get it out that way. Then, to remove it, you turn it and pull it down and out.
This back one, you actually have to remove the drive shaft if you want to remove this entirely. You bend it out of the way. Then you want to lower your jack. Ideally you're going to want to have your truck about two feet off the ground to have enough space to do that. You're bringing the front of it down and then you kind of slide it forward to get it out. On the back of it there's a harness right here. You want to lift up on that tab and disconnect that harness. Then, from the front up on top of the gas tank, there's another harness. Again, just lift up on the tab and disconnect it. Then have someone help and hold the other side of the gas tank. Remove that jack stand and if you're lower to the ground because you're using standard jack and jack stands and not a lift, you won't necessarily need two people. You can just move it out carefully. You also want to make sure that this is as close to empty as possible. You want to work it down and this strap on the back may get in the way. Just lift that out of the way. Then your tank is free.
Okay, so you can see here this is just really in bad shape. These are all crusty, they're probably leaking. It could even be leaking right through the top of here. This is all fuel around the sides. We're just going to clean this all up and get rid of all this junk. Then remove this and replace the sending unit. All right, so these should push in and then you should be able to push these tabs and disconnect, but these lines are so rusty I have to actually clean it out in here I think before I can do it. We did the same thing to this one. We dug out underneath and we got the clip to unlock. It looks like it's actually going to come off. It just takes a little bit of convincing, I guess.
All right, so now we're going to remove this which is held in by retaining ring. There's a little lock here that you have to push that way. I'm going to use my chisel to get the ring moving. Once you get the ring free, carefully lift it off of the fuel pump and sending unit, and you want to make sure that you're not letting any rust fall down into the tank or any dirt. You want to do this very carefully. Then just lift the fuel pump and sending unit module up and out.
I'm going to very carefully try and clean this without getting dirt in the tank at all. Wipe around and then out. Up and around, out.
All right, so we went and dumped out some of the gas, and you can see we got a lot of the junk out of there. A good way to kind of filter gas is to get a funnel with a filter in it and then take a paper towel and put it down in the funnel. The paper towel is going to actually funnel the gas to a finer extent. It takes it some time, but you pour the gas in and it soaks through the paper towel. Then we don't pour, we wait, once we get to that sludge at the bottom we just stop. You can see how much the paper towel picked up. We actually are going to kind of drain the tank, and I'm not one to give up gas so we'll feed the gas in like that.
On the left is the old fuel pump and sending unit; on the right is the new one from 1A Auto. You can see they're identical and they'll fit exactly the same. Now remove the rubber washer and that clip, and you want to do that from both of those and remove the packing caps from the new fuel pump and sending unit. Then push on the clip and the rubber washer.
Feed your new fuel pump and sending unit down into the tank. Take that retaining ring and lower it in place. Then, using the hammer and the chisel, you want to just knock that back into place until that clip re-clips in.
Now reconnect your hoses. This may take a little persuasion.
Now we're going to re-install. Can't go all the way up yet. That looks good. Reach up in, find the harness. Reconnect this harness at the top of the fuel tank, clip in your gas tank strap and replace the bolt. To get the other gas tank strap in if it fell out when you were putting the tank up and in there, you're going to have to remove these four 11mm bolts with an 11mm wrench. Then you want to just put those brackets and bolts back in a little bit so that when you go to remove the drive shaft it doesn't just go flying off. Take a hammer, hit it a couple of times to loosen it up. Then, using a pry bar or a large flat blade screwdriver, just pop it out. Once you get it to break free you can remove those brackets. Then pull the drive shaft down and put the gas tank strap back up into place. Once you get it in place, put the drive shaft back in and just use a hammer to tap it back into place. Then replace those brackets and the 11mm bolts and tighten them all up.
Then replace the bolt for this gas tank strap and tighten up both the gas tank strap bolts. Now you can lower your jack stand and remove it.
We'll reconnect this harness up here and then reconnect this other harness. Push your fuel tank filler neck hose back into place. Once you get it all the way pushed in you want to just slide that hose clamp up into place and tighten that up.
Reconnect the fuel lines and then just push them in to place.
Reconnect this line then replace the crossbar and the four 15mm bolts that hold it in place and tighten them all up.
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