Hello. My name is Mike and this is my first post on this forum. I've been driving a silver 2004 FWD Vibe since 2018 but this car has been in the family since new.
I just swapped out my rusted metal tank for a 2007 plastic tank from a scrap yard Matrix. My gas tank has been leaking at the seam for a while now and have been putting off a swap due to a lack of data about such a swap. I can confirm that it is possible, but is most definitely not a direct bolt in swap. Disclaimer: I am not a mechanic, so if you see something in my post that looks like I did it wrong, then I probably did
I started the process by making a scouting trip to the U-Pick scrap yard near me to see what they had. Found a 2007 Matrix almost entirely intact. Next step, pull out my tank and look at what was needed off the 2007 Matrix before going in the scrap yard with the tools. I had already bought a plastic tank from another yard because this U-Pick yard drills out the tanks to drain the fuel.
What I ended up taking off the Matrix:
1: Fuel tank with pump assembly inside (took the tank straps with it + they looked almost new)
2: Charcoal Canister and all hoses attached to it (kept it attached to the tank when I pulled them)
3: Fuel filler neck (turns out the vent lines are different sizes, so the hoses to canister were different)
4: I clipped the wires from the fuel pump assembly and the canister because I had already seen that there were differences.
5: Unrelated Bonus items to the swap, sitting in the back of the Matrix were the two straps that come with the car (still have the Vibe straps) and a bag with the little attachment points that screw down into the sliding rail for the back of the car (I use mine all the time so now I have extras).
6: Took the heat shield, but it's rotten at all attachment points so I grabbed it to eventually use it as a template for bending a new one.
Main differences and similarities between models:
1: '04 Vibe has two elec. connections at the top of tank. One for fuel pump assembly and one for tank pressure sensor (I believe that's what it's called). The '07 Matrix has only the fuel pump assembly connection and it's wired the same as the '04 (It's the same connector)
2: '04 Vibe canister only has 2 wires going to it for the vent valve (not sure if that's what it's really called. The '07 had a 7 wire connector on it. It had the pressure sensor at the canister along with the vent vale and a leak detection pump.
3: The gas tank straps are different. The '07 straps bolting right in holding the plastic tank in place.
4: Possibly the biggest difference and largest modification was the hole in the floor for the pump assembly. The '07 tank was too far forward and the pump assembly touched the floor (almost cleared).
5: '04 Vibe has 3 fuel system lines running to the front of the car (fuel supply line and two related to the EVAP system). '07 has only 2 lines (fuel supply line and one EVAP line).
Here's what I did to the '04 Vibe to pull this swap off. I didn't necessarily do all this in the order listed because there was some trial and error and refitting that had to happen. The easy stuff started with swapping out the fuel filler neck. It uses all the same bolts on the inner fender well. swapped the fuel pump assembly from the '07 Matrix (remember the tank had been drilled out to drain by the yard) to the one I got from another yard. Put the tank in the car with the '07 straps. Bolted up the charcoal canister from the '07 after drilling out 2 of the 3 bolt holes that had broken off removing the old one. Connected up all the hoses from the filler neck, canister and tank as they were in the '07 Matrix. I couldn't really find any info on the '04 EVAP system online, so I had to guess on which of the two EVAP system lines to use that go up to the engine compartment. One of them goes up towards the top of the air intake box and has a test valve (schrader valve???) on it. I hooked up to that line. The second one on the '04 runs to some kind of sensor or switch that has an electrical connection in it and then connects to the air intake box lower on the side. I can't find what that thing is called. It's currently not connected to the EVAP system at the back right now for lack of hoses off the canister of the newer car. I cut the electrical connector on the top of the fuel pump that goes to the pressure sensor and extended the yellow, brown, blue wires to the charcoal canister and wired them up to the canister's connector matching wires (found an '07 wiring diagram to confirm that's where the pressure sensor went). I also wired up the black and red wires going to the original canister to the 'same connector as the pressure switch wires matching the black and red wires. I was left with a grey and a white with black stripe wires not connected. It seems they are for the leak detection pump on the '07, but I couldn't find where this would be on the '04 so I'm assuming it's not on the car until I find out otherwise and left them wrapped up with the other wires in that cluster. Before the tank was fastened in, I cut the access hole in the floor larger (close to 50% larger) towards the front of the seats to give proper access to the fuel pump assembly and made a new cover and just used sheet metal screws to fasten it to the floor. This curved cover also gives a bit of room for the top of the fuel pump assembly for clearance.
In the end it all seems to work, except for a potential gas gauge issue. When first turning on the key after the swap, the gas gauge didn't move. It sat below empty (normal resting state when off) and the low gas level light was on. After some messing around and watching some YouTube videos I couldn't determine why it didn't work. The amount of gas added to the tank after the swap should have moved it to 1/8 of a tank or more. I drove the car to the closest gas station and filled it up. When I got in the car and started it, the gauge was reading full (not quite to the top of the full line). Time will tell if it reads empty when it's got plenty in it. Might take a week of driving to work to figure that out.
I think I covered everything there, but I do have a couple questions that I hoped someone could answer. 1) If the ohm range for the two fuel sending units were reading different, would that be why the tank was reading empty until it was filled. If so, would it be advised to go back to the scrap yard and grab the fuel gauge that went with that sending unit to read accurately. I didn't really know what I was doing but I watched a video on testing the ohms of the sending unit to see if it worked. The '07 unit was somewhere around 300+ ohms empty down to 15 when the float was lifted all the way up. The '04 unit was just over 100 ohms at empty and less than 15 when all the way up (full tank or more). Could it be that the gauge thinks that 100 ohms is empty and won't move up until the newer sending unit gets to that part of it's range? Or am I looking at this all wrong
. 2) Can someone tell me what the second line, or maybe it's easier to say what both lines coming from the charcoal canister to the engine compartment go to on an '04 Vibe? Probably applies to an '03 as well.
If you got to this point, thank you for your patience, and I hope it all made sense