Installing ADM FPCM and ZL1 pump through an access door

[Hardymon]

This is a DIY for installing the ADM FPCM and ZL1 fuel pump by cutting an access door instead of dropping the tank. I know that a lot of people feel this is the "wrong way" to do it, because you should never cut on your car, blah blah blah, but some of us don't plan to go over the 600 or so rwhp mark, and don't feel like spending the 6+ hours to drop the entire rear cradle and gas tank. That said, if you're in the "this is wrong" crowd, your feelings have been acknowledged, please don't post that here. As a note, photos are at the end, I was having trouble linking them for some reason.

I will say, this procedure does involve some risk, does require some precision, and I take no responsibility if you try this and damage something. This post is only to provide those who are interested with some information so that they can hopefully make an informed decision and proceed accordingly.

As to the risk/precision warning, the gas tank is extremely close/basically right against the seat pan in most places. It's hard to appreciate in the pictures, but your margin for error in terms of the depth of your cut is VERY SMALL. If your cutting tool of choice goes too deep, you will cut into the gas tank, electrical wires or gas feed lines. Hopefully my explanation will prevent you from doing any of these. The other thing is, that seat pan is not flat, so unless you have a friend with an English wheel or some other means of shaping the metal, you will need to use a lighter gauge metal that is more flexible, so consider this as well. The new FPCM does require tuning adjustments, so if you don’t have HP Tuners/EFI live, plan accordingly. Lastly, do this as close to an empty tank as you can. I thought I could get away with doing this on a 1/2 tank and still ended up spilling a lot of gas in my friend's driveway. I think that does it for the warnings now, let's get to the good stuff!

Step one: Removing the back seat. Estimated time: 10-20 mins

This is pretty basic, there is a single tab roughly centered on each seat well, (2 in total), that just need to be pulled up. Slide your fingers along under the seat until you find each tab and then just pull straight up. The seat should pivot up. Push the seat belt latches through the seat. There are 2 bars in the back of the seat that hold the rear of the seat. Slide your fingers into the break between the upper and lower portion of the seat and slide the seat covering off of the wire retainers. Now the bottom portion of the seat should be free and can be removed.

The next step is to remove the top portion of the seat. Pull the loop as if to fold the seat down. After doing this, you will see a latch on both sides. If you can, try to release both latches. I was having an issue with my driver’s side latch and opted to just work around it, so this can be done, but I would recommend pulling it out entirely if you can.

At this point, the back seat should be out. The next step is to pull off the back passenger side trim panel.

I started by pulling up the kick panel as it is interlocked with and over the panel you need to remove. Once I disengaged the back trim from the kick panel, I started from the bottom and gently worked my way up to the top and then towards the back. Once you have this large trim panel removed, you now have access to the FPCM, and a little more room to work on the access door.

Step 2: Installing the ADM FPCM. Estimated time: 5 minutes

Once you have the back trim panel off, you will see a little black box with a bunch of wires going to it. First, disengage the wire connector. This is accomplished by pulling back on the small red locking tab and then pivoting the locking clamp towards the front of the car.

With the wire harness disengaged, remove the single nut from the stud. Once the nut is off, pivot the FPCM towards the back of the car and pull it out. (There are a pair of tabs holding the other side in)

Simply reverse these steps to install the new FPCM. Tuning WILL need to be done to make this run properly.


Step 3: Cutting the door and installing the pump. Estimated time: 1 hour

The first thing to do is bleed the pressure out of your fuel line. There is a little Schrader valve covered by a black plastic cap on the front of the driver’s side fuel line. Place something very absorbent under and slightly in front of the valve before you bleed off the pressure because there is a good bit of gas in there and it’s under a good bit of pressure.

Next, plan your cut. Mine was about 7 ¼ “ wide by about 8 ½ “ tall.


I measured the width starting about a ¼ “ from the dip where the rubber grommet with the electrical wires goes through. If you go much to the passenger’s side then you’re going to interfere with the grommet, or be over too much of the pump. I measured so that my “driver’s side” cut would land between the 4th and 5th ridge in the seat pan.

I selected my height basically by just cutting to the outside of the ridges of the pan so that I could ensure a nice flat surface for the door to mate against. (Again, when I say flat, that’s relative, the pictures don’t show all the contours of the seat pan). If I were to do it again, I would probably have cut a little bit of a scoop instead of a straight line since I had more than enough room height wise and it would have left more material to mate against.


Please look closely at the pictures as this should be about how your lines are run. Note how close they run to the surface of the seat pan. When you make your cuts, be extremely careful with how far you let your blade go through the material. In addition to the lines that run through here, be aware, the way I made my cuts, in the corners, the gas tank is nearly touching the seat pan, so be very careful in the corners as well.

After you make your cut, the rest should be relatively easy. Start by disconnecting the wiring harness from the pump and then remove the clamp blue clamp from the fuel line and pull the line off of the connector. (Have some rags ready as there may still be a little bit of pressure and gas left over, be aware, it may still squirt a bit, even in spite of relieving the pressure in the line).

At this point, try to have some sort of bucket available to catch the gas that will be trapped in the pump housing when you pull it out. After everything is disconnected from the top of the pump, remove the retaining ring with the retaining ring tool or by hitting a screw driver placed into the notches on the outside with a hammer. It will require some firm hammering, but if you’re careful, it can be done this way without damaging the ring. If you’re not confident, see if your local parts store will rent you the removal tool.

Once you get the ring off, gently begin to lift up on the pump. (Take not of the orientation as the new pump will have to go back the same way). You will need to lift and pivot the pump to clear the fuel level sensor and the line on the bottom. The hose on the bottom of the pump is a quick connect and is released by pressing the green button and pulling gently.

Once the pump is out, you will likely need to transfer the fuel level sensor to the new pump. This is done by taking the two wires, (one each on the left and right side of the sensor), out from under the retaining hooks and disconnecting the wire harness from the pump. Now that the wires are disconnected, press gently on the two tabs on the sensor and slide it up and out. Install it in the new pump by performing these steps in reverse.

With the level sensor installed on the new pump, reconnect the quick connect line from the gas tank to the bottom of the pump and start working the pump back inside the tank. Place the locking ring back on and then reconnect the supply line and the electrical harness.

Now that everything is back in place you need to put a panel back. You have a few options available to you at this point depending on what’s available to you. You know your abilities and resources, so I’m only going to cover the way I did mine.

I’m fortunate enough to have a friend with an English wheel, so I opted to go with a heavier 16 gauge steel plate to make up for the rigidity that the ridges provide in the thinner steel. I cut the plate so that it would overlap as much as possible, which is not a lot on the front and passenger’s side, maybe about ¼ “. The driver’s side had plenty and I neglected to factor in the slight shrinkage of the outer diameter when I formed the plate, so I was a tad shy of where I would have liked to be on the rear side, but I still had just enough. After I cut and formed the plate, I marked where I wanted my holes and drilled very carefully, again so as to avoid puncturing the tank. I deliberately placed the screws where I knew there was both enough space, and nothing important would be running under them, and they would secure the contours of the pan without leaving big gaps.

After my holes were drilled, I primed the plate and the edges of the hole to help prevent rust. After the primer was dry, I ran a generous bead of RTV auto/marine sealant around the rim of the hole. I then screwed the plate down using 3/8” #8 sheet metal screws. As a belt and suspenders measure, I added a second generous bead of sealant around the outside of the plate.

After this, it’s time to put everything back together. Put your trim panel back in first. Again, I started from the bottom of the door and worked up and back. Then comes the upper part of the back seat, this should just drop back into the latches on either side. Finally, the lower portion of the seat. Start by hooking those bars under the wire hooks on the back, then maneuver the seat-belts up through the holes. At this point, everything should be fairly lined up and the tabs in the front should just push in. Congratulations, you’re done!

[hammdo]

A few have actually just removed the 2 font rear cradle bolts to drop the cradle just enough to remove the tank, but as you said, your car and you choice... Sure looks easier your way...

Thanks!

-Don

[hou30guy]

What tool can i buy at harbor freight to cut the metal

[Hardymon]

I just used a 4" grinder with a cut-off wheel.

[caper]

just wantedto say thanks for this write up! i just did this and it really helped. i also 2nd the less gas tip. i had no choice but to do it with a 1/2 tank....ohboy that was allot of gas on garage floor! dangerous actually. also i plan on using the panel i cut out for the door and just using some silicone etc to put it back on. no need for a new piece. also yes the margin for error is very very small in the corners - as in 2mm. i used a dremel and just imagined scraping away not just cutting. take your time.

[Iam Broke]

Thanks for the well documented procedure to do this, I did it a few years back but your procedure is much better to follow.

[ZX1truth]

Thank you for the excellent write up.....this is the way I'm going with my dremel!!!

[Hellboi]

Could you still drive the car before the tune or would you need to tune it right after the install?