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How to replace the fuel pump

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Car is a 1994 GT.  I wrote this up for my blog:  geargambler.blogspot.com.  You can add whatever pump you want or replace the assembly all together.  Here is what went down for me!  


It finally happened.  I pulled into the gas station, shut the car off, filled it up.  When I tried to start the car again, it just cranked and cranked without firing up.  I hit the key a few times listening for that familiar noise from the fuel pump priming - Nothing…


The helpful guys at the station pushed me into a parking spot where a tow truck could scoop me up.  They pushed, I steered.  Tow truck came and brought me home to my place, frustrated.


I KNEW that the pump would eventually fail.  I'm really glad it wasn't while I was on a road trip across the nation.  I already have a new pump - Walbro GSS307, a new gasket and a new filler neck grommet.    While cruising around online I found deals on these things, and I picked them up and kept them in the car just in case I was in a remote place.  At the least, I didn't have to wait for the parts.


Back to the fun.  I did have to wait a few days because of other priorities, but I finally got some time to get the car up in the air.  Here is what went down!



I jacked the car up and got some jack stands under the subframe connectors.  Then I moved the jack under the gas tank, and jacked it up under the car.  Now remember, the gas tank is absolutely full.  There's no way to syphon fuel out (the 95 fuel neck prevents exactly that), and the pump is dead, so I can't pump it out.  I removed the bolts for the straps that hold the tank up.  I removed the retainer for the filler neck - single bolt that goes through the tank frame.  Then I began to lower the tank.


At this point i realized that fuel escaping the tank was inevitable.  I got out my large catch pan (same aluminum pan used to catch water under a hot water heater).  Its BIG and offers the best chance to catch the fuel.  I also got a two empty gas jugs (VP Racing of course!).  I figure the tank's capacity is 15 gallons, so getting at least 10 out of there would be great.


Back to lowering the tank.  As the tank came down, I worked to remove the filler neck.  This is the tricky part.  I sprayed some wd40 around the neck and inside the grommet and that helped free it up.  I needed to lower the tank and move it toward the passenger side in order to remove the neck.  As soon as the neck was removed, fuel began to spill out, all over the place, right into that big aluminum pan!  I'm so glad I had that.  So while this was going on, I now had a way to get the fuel out.  I got an old fuel line and put it in the tank through the filler neck hole.  I syphoned the fuel into the fuel jugs.  By the time I was done, I got out about 7 gallons.  This was enough for me.  Note:  to start the fuel flowing, I sucked on the end of the fuel line until I got a mouth full of fuel.  It was awful and I do NOT recommend this.  I washed my face and used some mouthwash and that helped.  By the time I was done cleaning up, the first jug was full.  I moved onto the second jug and stopped after about another gallon in there.


I moved those out of the way, and plugged the filler neck hole with a rag.  I lowered the tank a bit more and disconnected the electrical for the fuel level sensor and the fuel pump.  I also removed the vent line that goes through another grommet.


The fuel lines were a bit tricky.  There is a clasp on top of each line (feed and return).  The feed is the bigger line, and the return is the smaller one.  Once those two were removed via a screw driver prying them away, I moved to the lines themselves.  Starting with the return line I pushed it ON TO the fuel pump.  Using a fuel line disconnect tool (look it up), I pressed it into the end of the line while pushing it towards the fuel pump.  this releases the 'catch' inside the end of the line.  Then I pulled the tool and the line away from the pump and it came apart - spilling some fuel in the process.  I did the same exact thing, using two sizes up disconnect tool, to the feed line.  At this point the tank was free of any connections to the car.


I plugged the vent grommet with another rag and lowered the tank carefully.  Balancing it on the jack while fuel is sloshing from side to side is a chore to say the least.


Pump Removal:

Using my air tool blow gun attachment, I cleaned up the top of the tank.  20 years of road grime and gravel can really build up.  I paid special attention to the area around the top of the pump.  I wanted this to be as clean as possible so that nothing fell into the tank.  Once I was happy there, I moved onto removing the pump.  There is a cap on the top that needs to be loosened.  You do this by hitting each of the upright tabs in order to move the cap in a way that loosens it.  Now the next part is very important.  You cannot use steel here or anything that will make a spark!  Remember, you are working on a fuel tank here!  I used a brass punch and a dead blow hammer - no metal.  I hit each tab, working my way around and eventually the retainer ring was free.  I noted the orientation and worked the hanging assembly to remove it.  It is not straight, so there was some twisting involved here.  I also made sure to remove the O ring along with it.  It is basically the gasket between the pump assembly and the tank.  I was also careful not to loose the boot / filter on the bottom of the assembly.  Once it was close to the top i used the brass punch again to pry it out of the hole.  I made sure it was in hand.  I've lost these a few times inside the tank and its a pain to get it out.


Pump Replacement:

Now that the pump assembly was in hand, I could remove the old pump.  There is a hose clamp for the hose that goes to the feed line.  I loosened that, and removed the hose.  Then I unplugged the pump electrical leads and removed the boot / filter.  I had to change the negative lead to a larger female flat blade connector, insulated.  The positive lead is not insulated - I don't want these two to make contact!  I installed the rubber grommet that goes between the bottom of the new fuel pump and the assembly.  Then I installed the new pump - a Walbro GSS-307.  It has a built in screen unlike the stock one.  I installed the hose and tightened the clamp and finished up with connecting the electrical leads - making sure I had the polarity correct.  Then I installed the boot / filter on the bottom remembering that I have no idea how to orientate it.  I did mark how the assembly was orientated in the tank.  I held the assembly over the tank and looked for where the boot should sit.  I shined a light into the tank and a few adjustments of the boot and I was happy with the orientation.  I used a new O ring and installed the assembly.  I had to work it around a bit to get the boot into the 'compartment' inside the tank.  I guess it is there to prevent sloshing and fuel pump starvation.  Once it was sitting in there nicely, I made sure the O ring was in the right location and added the retainer ring.  I tapped the tabs like I did to remove it, just in the opposite direction this time.  You will see when it will not go any further.


I also replaced the filler neck grommet - I've heard of these leaking and the cost was cheap.  I pulled out the old one, sprayed the new one with some wd40 and installed it.  It took a little prying, but it went in.



I worked the tank back onto the jack and centered it.  I'm not going to lie, this took a minute!  I jacked it up enough to connect the electrical, installed the vent, the fuel lines (they just snapped right back in) and the fuel line retainers.  next I sprayed the filler next with some more wd40.  I had to work the tank to get the neck to go into the grommet.  After fighting this for a while, I opened the gas filler door, removed three bolts and had a lot more wiggle room.  I got the neck installed and continued to jack up the tank slowly.  eventually I worked it into place, but the fuel neck was not aligned in the fuel door.  I had to lower it and center that neck so that it lined up with the three screw holes for the screws i removed before.  This was a frustrating process.  If there were two people one could stand there and hold it center, and the other could jack up the tank.  It was tough to do both.  I eventually got it right and installed those three screws.  I moved the tank into place and was able to re-install the straps.  The last step was to install the filler neck retaining screw to the tank, and the gas cap.



While the car was still up in the air, I got inside and turned the key to prime the pump.  I turned the key off, did it again and started it.  It cranked it over and started!  I jumped out and looked for leaks.  Nothing (thankfully)!  I shut the car off and opened the garage doors.  Remember, its winter here in the Poconos so it was COLD.  I warmed the garage up before I started doing anything, but I shut the heat off once I started smelling fuel while I was working.  I needed to air it out.  While that was going on, I filled the tank up with the fuel I syphoned out.  I jacked it up and removed the jack stands.  Then I lowered it down.  I cleaned up my tools and took it for a ride.  It seemed OK!


One thing I did notice unrelated to the fuel.  In the process of pushing, towing and getting the car back into my garage, I had turned the wheel a few times.  This caused the power steering fluid to overflow from the pump.  On the test drive the pump was whining.  I did some very slow oscillations of the steering wheel, lock to lock, to work the fluid back and forth and it seemed better.  While I was out I picked up some power steering fluid just in case.  Then when I got back, I cleaned up the PS fluid that had dripped onto my garage floor.


The car seems fine now.  I drove it a bunch but did not commute with it.  If anything goes wrong, I'll report back!







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I agree, thanks for taking the time to write this up. I HATE doing a fuel pump, but sometimes there's no way around it. Last time I did mine, my house smelled like gas for a couple days...my wife was overjoyed... lol

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I agree, thanks for taking the time to write this up. I HATE doing a fuel pump, but sometimes there's no way around it. Last time I did mine, my house smelled like gas for a couple days...my wife was overjoyed... lol


Same as mine when I did it.  I swear the 4 of us need to hang out.

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i have honestly never dropped my tank in the 10 years ive had the car.... 




and now it is going to die the first time i drive it this spring.

you totally JINXED yourself there.




Mine is going to get pump number 4 when i put the new motor in....it will be its second 255lph. The first one burned up which is why its rocking a stocker right now lol. Great write up btw

Thank you!  If it helps just one person, then it was worth it.

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