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Knowing what I know now, I say go for it, lol.

That big hump in the middle is where the fuel pump assembly is located. The flat area with the tire hold down should be where the solid portion of line runs. The top of the tank should match mine and comparing pics should help judge where to cut.

This a picture of the removed piece stuck back on. My plan was to secure it properly at a later date but I had to pull the thing yet again and slapped it back on even worse. It's on my 'one of these days" list.



EDIT. Once you have the tank out of the way, looking at the floor from below makes what to cut a lot more obvious.
 

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Discussion Starter #22
Knowing what I know now, I say go for it, lol.

That big hump in the middle is where the fuel pump assembly is located. The flat area with the tire hold down should be where the solid portion of line runs. The top of the tank should match mine and comparing pics should help judge where to cut.

This a picture of the removed piece stuck back on. My plan was to secure it properly at a later date but I had to pull the thing yet again and slapped it back on even worse. It's on my 'one of these days" list.



EDIT. Once you have the tank out of the way, looking at the floor from below makes what to cut a lot more obvious.
Thank you so much for sharing - obviously the wagon is different, but the hole is smaller than I figured it might be. Going off that, I'm guessing the sedan hole might look something like this?

196789
 

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Not sure if this helps at all, but I made a hatch to clear my Aeromotive Phantom twin pump setup. I had to extend the bump in the trunk a little further towards the rear to clear the phantom hat, and my factory sending unit comes out a bit easier since the lines are cut short/pinched/capped to seal them off. If I were to make one for the factory setup though, I'd probably just cut the area around the hump out, weld flanges onto the sides of the cutout piece and then mount it the same way as mine with studs welded to flat strips and inserted through the floor from the bottom and nut-serts on the top portion. Even better would be to weld nuts into the top half so they don't hang down as much but I got lazy lol.

I do need to cut the studs shorter and put some cap nuts on them or something for a cleaner/more flush look but overall it does the job. You could use a gasket material of your choice on the flange and the whole thing maintains the structure of the trunk. Only issue is if you decide to crawl into your trunk, you may kneel on a stud which wouldn't be fun LOL.


IMG_0932 by Kris A, on Flickr

IMG_2479 by Kris A, on Flickr
 

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Discussion Starter #24
Not sure if this helps at all, but I made a hatch to clear my Aeromotive Phantom twin pump setup. I had to extend the bump in the trunk a little further towards the rear to clear the phantom hat, and my factory sending unit comes out a bit easier since the lines are cut short/pinched/capped to seal them off. If I were to make one for the factory setup though, I'd probably just cut the area around the hump out, weld flanges onto the sides of the cutout piece and then mount it the same way as mine with studs welded to flat strips and inserted through the floor from the bottom and nut-serts on the top portion. Even better would be to weld nuts into the top half so they don't hang down as much but I got lazy lol.

I do need to cut the studs shorter and put some cap nuts on them or something for a cleaner/more flush look but overall it does the job. You could use a gasket material of your choice on the flange and the whole thing maintains the structure of the trunk. Only issue is if you decide to crawl into your trunk, you may kneel on a stud which wouldn't be fun LOL.


IMG_0932 by Kris A, on Flickr

IMG_2479 by Kris A, on Flickr
Thanks for sharing! Based on that, I'm thinking the hole for a stock setup could be even small still?
196802
 

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I think you will find that you have to go further toward the front to let the sending unit lines clear the floor. You could cut the smaller hole and then get a better idea of how large the hole needs to be.

Ken
 

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An alternative approach to doing this that you might consider...

If you look in a junkyard for 90's front wheel drive cars, they have fuel pump access panels that are about 6x8 oval shaped and have a rib with gasket around them using wood like screws to hold them down (typically 10mm hex head or phillips). You'll need to find one that fits the "dome" in your floor and still allows access (which will be tight). Volkswagon jetta's, golf's, etc (99.5-06+) have similar panels under the rear passenger seat that might work?

This will make the access clean, sealed and only the size it needs to be, however this then requires modifying the fuel lines and electrical connections.

There are many ways to do these modifications to suit your preference...
They make tube adapters for flare fittings that would be clean, easy to change through the access hole and reliable. You only need something like this on the pressure line. The return line and vent line could just use hose pushed on and spring clamps. No harm in doing all 3 lines like this though.

Male end - https://vibrantperformance.com/cata..._1447&osCsid=200c3be8db66745455d0ada4d593c6b3
Female end - https://vibrantperformance.com/cata..._1446&osCsid=200c3be8db66745455d0ada4d593c6b3

Modify your current pump and a spare pump to have these connections (reverse the genders on like sizes so you don't mix them up :)). Just cut the hard lines close to the sending unit so they can be accessed through the cover. Leave the OEM connections in place up by the axle.

Now all that's left is the wiring - A simple MP150 series 3 position connector (just like the OEM one) can be similarly located near the pump for easy R&R. Again, modify your current and spare pump to have these connectors.

Easiest (though expensive on a per part basis) is something like this from Ballenger. Pick a mating pair of any 3 position of sealed connector (MP, GT, DT, etc)

If you want to assemble this yourself (and plan to do more wiring...) Waytek is the best source I've found.

This should give you 100% top side change out capability without huge cutout holes.

Hopefully I've explained this well enough - let me know if there are areas that are unclear and I'll try to fix that.
 

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Please forgive me for offending, but this may be one of the most ridiculous threads on any forum I've seen. I've been in the automotive business for over 25 years. There are some car manufacturers that put access holes for fuel pumps, but they almost always require significant labor to remove the tank. Our cars do not require significant labor. 2 straps, fuel lines, filler neck, and a plug. I know aftermarket part quality is not very good, but don't cheap out. Buy the best parts available and you won't do this more than every 100k plus. Make sure there's nothing in the tank that can cause the pump to fail (debris, bad fuel). Use good fuel, ethanol free if you don't go through a tank in 6 weeks. Keep the tank from going below 1/4 tank at the minimum. The fuel keeps the pump cool extending its life. Make sure to properly diagnose your issue. I've seen people throw the same part at a car over and over assuming it's a defective part when its really something else. The Fuel pump is usually the first part to throw. Nobody should be changing a fuel pump on the side of the road either.

If you lack the skill, tools, or space to properly diagnose and work on a car, take it to a professional. Cutting a hole in a perfectly good floor or trunk pan that isn't available to buy is ridiculous. I believe these cars will be worth some money in the future. Don't do something that you will regret later.
 

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I'm not saying I would do this mod but as a thought experiment it's better than half the crap I waste my time on on the internet.

-Brian
 

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BMX, that drawing you made seems to be about right but I think you may be able to make the top part a little shorter. i THINK, it's hard to say since my hard lines are cut short and I don't remember exactly how long they were, but I feel like cutting up to that first bead roll in the sheet metal may be enough.

Podor, to each his own. I used to feel the way you felt about cutting up a car but for me, this was my first car and i have years of labor into it. I'm never going to sell it, nobody is ever going to know the trunk was cut up except me and anyone I wish to share it with and other than it 'not being original' it does absolutely no harm to the mechanical function, look or structural integrity of the car if done with some thought. Not to mention, if I ever wanted to convert it back to stock I could always find a trunk from a donor car, cut the section out and weld it back in, grind the welds down flush and I guarantee you even the best of body men wouldn't be able to tell if it were ever altered after paint.

Personally, if I didn't HAVE to cut my trunk for my aftermarket fuel setup, I wouldn't have seen the need to either because as you said, dropping the tank isn't too hard of a job. But Chicago Area BMX races his car often, and in my experience with race cars ANYTHING you can do to make replacing or diagnosing ANY part of the car quicker and easier is worth its weight in gold when you're stranded in the pits with limited time and limited tools. Carry a spare pump with you and the hatch makes replacing it a 10 minute job. One less thing that can down you on race day.

Honestly, with the quality I have seen on so many new aftermarket and even OEM parts these days and how parts supposedly ethanol compatible end up shitting the bed after a few hundred miles on 10-15% mixes like we have here in NY, I couldn't blame anyone for doing it. The quality of replacement parts has plummeted over the last decade or so to the point where I wouldn't be so confident my replacement pump would last 75k or even 25k miles anymore.
 

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BMX, if it helps, I can measure from that first bead roll to the BACK of my sender (i'll circle where on a pic) so you can compare that to the length of your hard lines and see if the space would cover it.
 

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Discussion Starter #31
BMX, if it helps, I can measure from that first bead roll to the BACK of my sender (i'll circle where on a pic) so you can compare that to the length of your hard lines and see if the space would cover it.
Thanks for the offer, but after Podor flamed my thread, I think I'm going to sell the car. To him. Since it's so cherry and easy to work on, especially with 20 gallons of fuel in the tank, in a parking lot. :giggle:

No but seriously I appreciate the offer, but I was under the car last night eyeballing that area and it looks like the connections are right between the first ridge and the spare tire hold down. What you said about swapping the pump in the paddock in 10 minutes is exactly my reasoning. Track time is literally $2 to $3 a minute, so a little homework to make my day go more smoothly and save time/money when at the track is pretty priceless.
I'm ok with having to crawl underneath to disconnect a few things. Hell, I'm ok with unbolting the straps and lowering the tank a bit on a jack if it means I can reach connections and swap the sending unit through a hole on the top. What I don't want is to have to wrestle a tank with 15-20 gallons of fuel in and out of the car by myself, laying on my back, with just a floor jack and some stands, in less than the hour that I have between sessions. Or on the side of the road. 🤞
 

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Discussion Starter #32
An alternative approach to doing this that you might consider...

If you look in a junkyard for 90's front wheel drive cars, they have fuel pump access panels that are about 6x8 oval shaped and have a rib with gasket around them using wood like screws to hold them down (typically 10mm hex head or phillips). You'll need to find one that fits the "dome" in your floor and still allows access (which will be tight). Volkswagon jetta's, golf's, etc (99.5-06+) have similar panels under the rear passenger seat that might work?

This will make the access clean, sealed and only the size it needs to be, however this then requires modifying the fuel lines and electrical connections.

There are many ways to do these modifications to suit your preference...
They make tube adapters for flare fittings that would be clean, easy to change through the access hole and reliable. You only need something like this on the pressure line. The return line and vent line could just use hose pushed on and spring clamps. No harm in doing all 3 lines like this though.

Male end - https://vibrantperformance.com/cata..._1447&osCsid=200c3be8db66745455d0ada4d593c6b3
Female end - https://vibrantperformance.com/cata..._1446&osCsid=200c3be8db66745455d0ada4d593c6b3

Modify your current pump and a spare pump to have these connections (reverse the genders on like sizes so you don't mix them up :)). Just cut the hard lines close to the sending unit so they can be accessed through the cover. Leave the OEM connections in place up by the axle.

Now all that's left is the wiring - A simple MP150 series 3 position connector (just like the OEM one) can be similarly located near the pump for easy R&R. Again, modify your current and spare pump to have these connectors.

Easiest (though expensive on a per part basis) is something like this from Ballenger. Pick a mating pair of any 3 position of sealed connector (MP, GT, DT, etc)

If you want to assemble this yourself (and plan to do more wiring...) Waytek is the best source I've found.

This should give you 100% top side change out capability without huge cutout holes.

Hopefully I've explained this well enough - let me know if there are areas that are unclear and I'll try to fix that.
I appreciate your diligence, and I'll definitely check out what you linked more thoroughly, but my initial thoughts are that I'd like to keep most of this stuff as stock as possible, for parts store availability, etc. Once the mods start on that kind of stuff I feel it's a slippery slope, and can lead to some issues down the line if I goof something up, which is not unlikely, haha.
 

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Please forgive me for offending, but this may be one of the most ridiculous threads on any forum I've seen. I've been in the automotive business for over 25 years. There are some car manufacturers that put access holes for fuel pumps, but they almost always require significant labor to remove the tank. Our cars do not require significant labor. 2 straps, fuel lines, filler neck, and a plug. I know aftermarket part quality is not very good, but don't cheap out. Buy the best parts available and you won't do this more than every 100k plus. Make sure there's nothing in the tank that can cause the pump to fail (debris, bad fuel). Use good fuel, ethanol free if you don't go through a tank in 6 weeks. Keep the tank from going below 1/4 tank at the minimum. The fuel keeps the pump cool extending its life. Make sure to properly diagnose your issue. I've seen people throw the same part at a car over and over assuming it's a defective part when its really something else. The Fuel pump is usually the first part to throw. Nobody should be changing a fuel pump on the side of the road either.

If you lack the skill, tools, or space to properly diagnose and work on a car, take it to a professional. Cutting a hole in a perfectly good floor or trunk pan that isn't available to buy is ridiculous. I believe these cars will be worth some money in the future. Don't do something that you will regret later.
You're forgiven for offending.
You're also forgiven for not seeing this from the perspective of quite possibly the final generation of automotive enthusiasts who BOTH
A. actually drive the everlovin schidt out of their 26 year old cars because they're STILL awesome to drive
B. actually work on their own cars whenever possible (within reasonable limits depending on local circumstance)

The ISSF has already been saying the whole 'clean tank, 1/4 tank minimum, diagnose it properly, don't throw parts at it' spiel for about 2 decades now; you're forgiven for judging this thread as ridiculous too.

If you lack the urge to help us make these cars easier to diagnose and work on, I can certainly understand, but the nanny state has nothing to teach us.
If you think cutting a fuel pump service access panel is ridiculous, use better evidence to make your case - unless you're uninterested in actually contributing to the ISSF's technical body of experience and knowledge, which (if you've read as many automotive forums as you vaguely imply) is (to be modest) exemplary.

(Roadmasters and Fleetwoods are already escalating in resale value, by the way.)
 

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You'll also need to run the fuel pump wires through the access hole or you won't be able to pull them out as they are sandwiched between the tank and the body.
196919
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These are race cars, not show cars.
The way I look at it every car that exists today will be in a junk yard, crushed and shredded one day, but today, I own it and will have FUN with it!
 
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Discussion Starter #37
Thanks for the photo Nab. Somebody else may have mentioned it, but I didn't grasp the idea until you posted your photo. The wiring harness that comes off the sending unit is fairly long and connects at that plug all the way back near the rear bumper after looking under the car recently. Silly me to assume the fuel pump connector plug was ON the sending unit. Now that I'm looking at the photos of sending units, its obvious. Do you think there's enough space to thread the harness through if one unbolts the straps at either end and lowers the tank on a jack slightly? The reason I'm going through all this trouble is that I'm usually a one man show when I go to the track, and wrestling a full tank back into place by myself on my back seems like it'd really suck.

Also, I know folks have mentioned in the past having better luck with some sender assemblies than others?
Senders to stay away from? Looks like Delco is out of stock at RockAuto, but Dorman is avail for $134.
 

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Somebody else may have mentioned it, but I didn't grasp the idea until you posted your photo. The wiring harness that comes off the sending unit is fairly long and connects at that plug all the way back near the rear bumper
"5) The wiring disconnects back by the rear bumper, NOT at the tank."
Sinister's post #16 picture

Now all that's left is the wiring - A simple MP150 series 3 position connector (just like the OEM one) can be similarly located near the pump for easy R&R. Again, modify your current and spare pump to have these connectors.
You'll also need to run the fuel pump wires through the access hole or you won't be able to pull them out as they are sandwiched between the tank and the body.
The benefit to this is a separate ground wire from the rear lights, and shorter wiring for pump and sender.
 

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One can easily run a separate ground regardless, I did...
 

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Discussion Starter #40
Sinister's post #16 picture
Yeah makes sense now. I didn't compute that detail fully until today I suppose.

Do the Dorman sending units suck? I'm looking to order for a backup/spare to bring to the track with me, and looks like Delco is discontinued. Not sure where to find the Spectra.
 
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