View Full Version : How To: Replacing the Fuel Pump on 99-02 F-bodies

04-22-2013, 01:33 AM
This write up will take you step by step on how to replace your fuel pump on a 99-02 F-body. The process and assembly are a little different on the last four years of the fourth generation cars. These instructions might seem like a lot, but in hindsight, it wasn***8217;t too difficult. Let***8217;s begin***8230;

First, you are going to need to get your pieces and parts.



I got mine from HighFlow Performance and it includes everything you***8217;ll need. Here***8217;s the link.


It***8217;s a venturi style 255lph pump, good for up to 500HP. It***8217;s a good upgrade if you plan on going FI. Also, since it has the venturi valve, you won***8217;t have to modify your bucket and keep the tank above full. They also sell an OEM replacement pump here.




If you do the trap door method like I did here, you***8217;ll need a 12 x 12 metal panel to cover the hole you are going to cut. I just went with some 26GA for Home Depot.

BIG BEER (optional)


You will also need some odds and ends, like RTV, sheet metal screws, etc. to finish off the floor.

Ok, let***8217;s move on to cutting out the trap door.

Start by removing the two rear side panels and pulling the carpet back. We are going to only cut three sides, as to make a flap, instead of completely cutting the entire section out. Use this picture as your guide to cutting. I drew a ***8220;line***8221; across the bolt tabs for those tie down things we have in our hatches, and then cut down directly on the edge of those channels and right where the metal starts to curve in the back.


Bend the flap up like this.


Be careful what you cut this with, as the wires and fuel lines are rather close to the surface. I used a nibbler cutter, but others have used a Dremel tool or even tin snips. The metal is very thin and cuts easily. Here are a few pictures showing you how close the wires and lines are.




Next, we must relieve the pressure from the fuel lines. I pulled the fuel pump relay from under the hood and started the car several times to use the residual fuel in the system. I also depressed the shredder valve on the fuel rail to release any remaining pressure.



At this point, disconnect the negative wire from the battery. We don***8217;t need anyone getting blown up here.

Ok, back to the gas tank. Disconnect the two wiring connector. One has a little blue lock that must be removed to unplug the connector. Disconnect the three fuel lines by squeezing the tabs and pulls.


Now, there is a metal ring that twists into place holding the fuel pump assembly in place. This has to be carefully pounded counterclockwise to unlock. I used a hammer and a small pry bar, but you might be able to use a big screwdriver or something similar. Just be careful not to hit the tank. This ring was on there pretty good so expect to whack on it for a bit. Slowly the ring turned and eventually spun off.


Carefully lift the assembly out of the gas tank. The bucket is most likely going to be full of fuel. You will find it fits though the hole very tightly.

AS YOU PULL THE ASSEMBLY UP, BE VERY CAREFUL WITH THE FUEL LEVEL FLOAT AND SENDER!!! You will have to tilt the assembly to the right and angle the floater out of the tank. Have towels ready; you may spill some gas. Use extreme caution with this part, as it***8217;s very sensitive and you can mess up your fuel level reading. Once you get the assembly out, dump out the gas into a container or into the tank (it you can without making a mess***8212;I couldn***8217;t). I also taped up the floater to protect it a bit.



Cover the hole up in the gas take. I used a CD and and some duct tape. It closed it up pretty good actually. Take note of the rubber ring sealer around the hole.


Here***8217;s where I made my first mistake. I broke off the strainer on the bottom of the assembly.


Apparently, Autozone and Advanced doesn***8217;t sell these replacements. They do, however, sell the fuel pump strainer for the 93-98***8230; and mine had it in stock. It***8217;s an Airtex FS29 and it fit right onto the bottom of the 99+ bucket.



Now, we remove the smallest black hose from the venturi valve on the fuel pump. Mine was on there good and since my kit came with a new one, I simply cut it in half. You will need to remove/cut this hose to pull the pump assembly out of the bucket. It attaches to a valve on the bottom of the bucket.


Using a little screw driver, disconnect the red locking tab from the harness on the top of the assembly and disconnect the fuel pump and sending unit***8217;s wires.


Disconnect the plug from the motor.

Once this is removed, you can pull the pump assembly out of the bucket. Locate the two tabs on the side of the bucket and gentle push them in with a screw driver or something similar. Lift the assembly out of the bucket.

Note inside the bucket, there is this little floater thing. Not sure what it does, but know it***8217;s in there.


Remove the hoses from the pump, bucket and top of the assembly. I used a razor blade and cut them off, because they are on there GOOD. I didn***8217;t want to risk breaking something and since the kit has all new stuff, I didn***8217;t need to save it.


Mine kit came with this new wiring harness. The only thing is it doesn***8217;t include the sending unit. No problem. Get a stick pin or similar and locate the tiny slot above where the connection is made.


Push the pin into this hole. The connecter has a little tab that locks in into the harness. Push this down and the wire will come out.


The factory harness has a little brown secondary lock that further prevents the wires from coming out. Remove this and remember the two purple wires from the sending unit. You may have to lift the locking tab that you pushed down with the pin back up a little to make the wire lock into the new harness. Pay close attention to inserting the wire into the correct location. Do this for both wires and the harness is now ready for the new pump motor. Reinstall the brown locking tab.



The factory pump has a rubber case around it. Work this off. It***8217;s tight, but you will want to use it on the new pump instead of the one from the kit. Install this on the new pump, paying attention to the hole in the bottom for the new fuel pump strainer. I used a razor to widen the hole to make more room for the new strainer.



Once the rubber case is on the new pump, simply slide it back into place.


Now let***8217;s attach the new hoses. These things can be a bear. They are incredibly tight, but I found something that works great***8230; A HAIR DRYER. Heat the ends of the hoses up a bit and they slide right on.


First, start with the small black hose in the bucket. This can be a little tricky to get to.


Then attach the larger hose to the top of the pump and the top of the hosing. I used one of the supplied clamps of the pump side, but didn***8217;t see it necessary on the housing side due to its design.

EDIT: At the advise of the power manufacturer, I did install the clamp on the upper feed line as well. It is very tight, but apparently can still leak in some incidences.



Go ahead and plug the power harness onto the pump motor.


Now, slide the assembly back into the bucket. Pay attention to route the small black tube though the grove. Lock the two tabs back into position.

Heat the end on the black tub and connect it to the venturi valve on the pump.

If needed, install the new strainer to the outside of the bucket.

That***8217;s it. The fuel pump module is ready to be reinstalled.


Reinstall the opposite way you removed it. CAREFULLY! Remember the rubber O-ring. Lock the module back into place by tapping the locking ring the same way you removed it. For me, it went back on easier than it came off.

Reconnect the fuel lines, power and fold your flap back over.


Reconnect your battery and replace the fuel pump relay. Cycle the key on and off several times to pressurize the system. Check for leaks. If all seems ok, start the car.


I cut a 12***8221; x 12***8221; piece of 26GA sheet metal to make my patch panel.

I first applied a bead of RTV around the hole. I then screwed the sheet metal into place. PLEASE NOTE THE LOCATION OF THINGS WHERE YOU ARE SCREWING. Make sure your screws are short and the location isn***8217;t over fuel lines, the tank, etc.

You will need to bend the rear side down with a hammer like this.


That***8217;s about all there is to it. Pull the carpet back and reinstall the side panels.


Enjoy your new fuel pump!


04-22-2013, 09:33 AM
awesome write up. its quite different than 93-98 tanks.

04-22-2013, 09:07 PM
Excellent write-up! That huge beer is probably the key to success.

04-22-2013, 09:56 PM
Thats loads different from mine. On mine I had a fair bit more room from the tank to the floor.

Pewter six
04-23-2013, 12:18 AM
Very great write-up, Bone! I will need this in the future, especially the part about the trap door.

04-23-2013, 06:39 AM
Indeed, excellent write up!

One question though.
Would substituting the large beer with a six pack be acceptable? Also what about rum&coke? :P

04-23-2013, 09:36 AM
Thats loads different from mine. On mine I had a fair bit more room from the tank to the floor.

probably because our lines run to the front of the tank and then runs to the left side. those go straight to the pump.

04-23-2013, 10:04 AM
One question though.
Would substituting the large beer with a six pack be acceptable? Also what about rum&coke? :P

Perfectly acceptable.

04-23-2013, 10:10 AM
Sweeeet :P note taken!

04-25-2013, 01:52 AM
Great write up! Glad the install went well :tup:

04-25-2013, 06:06 AM
Thanks y'all.