This is a repost of madmaverick's fuel pump DIY:
My M3's fuel pump went out on my way to work a couple days ago, I had a suspicion it was on its last leg because it had been buzzing louder than normal the past week. I couldn't find a DIY on the forum and wasn't sure how involved replacing it was. (I did one a while back on my 92 mustang and had to drop the tank, no fun) Since I was already 180 bucks in the hole from the tow I decided to borrow a repair manual and tackle it myself so here is my DIY for those of you interested. This is not hard at all, dont even need to get under the car and no way would I pay someone else to do this!
First off I wouldn't jump right out and buy a new pump unless you are certain that it is the problem. The fuel system has fuses and relays that can fail and cause the pump not to run. Start by checking the fuses and accessing the fuel pump wiring harness to check for power.
Anyway here you go...
Slide both the driver and passenger seats all the way forward to give yourself as much room in the back seat as possible. (Luckily for me I have a vert so I dropped the top).
If your car has a ski pass remove the ski pass panel first and unhook the leather cover from the metal bar that goes across the ski pass opening.
Remove the rear seat lower cushion by lifting the front edge up, once it is unlatched pull torward the front of the car and set it aside.
on the passenger side you will now see a round rubber grommet with wires running to it, under here is the fuel pump access cover.
Pull forward the carpeting than pull back the rubber insulation to expose the access panel. (may need to slightly tear the insulation to get it started)
Loosen the four nuts on the access panel and remove the panel.
Now TEST the pump
Before going any further I would confirm that there is power to the pump and it isn't running.
While sitting as close to the fuel pump as you can have someone turn the key to run, if the pump is working you will hear it hum for a few seconds and of course if its not working you shouldn't hear anything besides some solenoids click and maybe the hydraulics prime up if you have a convertible.
Remove the wire harness by sliding the retaining clip toward the passenger side and pull up.
To test for power at the pump I used a digital volt meter and contacted the red and brown wires on the harness.
Turn the key to run and for a few seconds you should get a reading of 12.6v (my battery was weak from having the hazards on while I was broke down so I only got 12.29v) if you have another person to help they can turn the key forward as to start the car and this will keep a constant voltage running to the fuel pump, otherwise it will only get a few second prime from the run position (hope that made since). If you are not getting 12 volts to the pump you may want to look into the fuel pump relay or fuse for the problem. If you did get a 12v reading and when the pump was plugged in you couldn't hear it run, it would be safe to say your fuel pump is shot.
Fuel pump removal.
Unhook the negative battery cable.
Unhook the fuel line from the pump by squeezing the two clips and pull.
Now remove the retaining ring with either the special BMW tool or do what I did and use a hammer and screw driver. Place the screw driver tip on one of the notches of the ring and tap with a hammer, after a few hits move to the opposite side to prevent the ring from binding. After about a quarter turn it should get lose and easier to turn.
At this point put down some towels around the pump and grab a bucket to place the old pump into.
To remove the pump start by lifting strait up, there is a plastic hose you may need to manipulate a little to get past the tank. You will need to twist the pump 90 degrees and tilt it a little to keep the fuel gauge float arm from getting hung up inside the tank.
I recommend replacing the entire unit, fuel pump and gauge float. Its easier for one (don't have to swap pump from old assembly) and why not since your already in there. I bought the complete assembly from tischer for $225.
To install, First put the new rubber gasket around the new pump assembly but don't seat it around the top, fish the assembly half way into the tank. NOW seat the rubber gasket onto the gas tank and not the assembly. (makes life easier and less chance of pushing it into the tank)
Push the pump assembly down keeping the hose hookup in the same position as the old unit and line up the tabs at the rear.
Now hook up the fuel line and wire harness. Place the retaining ring back on and tighten it with the same method as removal and hook back up your battery.
Now Test.
Turn car to run, you should hear the pump run for a few seconds, I would cycle this a few times to be sure the pressure is built back up, now go ahead and fire it up. Hopefully all is good, bolt back down the access cover, fold down the rubber insulation, install seat cushions and done!
Hope this helps, it was super easy and hardly seems worth doing this DIY as it took longer to do than the fuel pump swap.
Peace
-Marty
My M3's fuel pump went out on my way to work a couple days ago, I had a suspicion it was on its last leg because it had been buzzing louder than normal the past week. I couldn't find a DIY on the forum and wasn't sure how involved replacing it was. (I did one a while back on my 92 mustang and had to drop the tank, no fun) Since I was already 180 bucks in the hole from the tow I decided to borrow a repair manual and tackle it myself so here is my DIY for those of you interested. This is not hard at all, dont even need to get under the car and no way would I pay someone else to do this!
First off I wouldn't jump right out and buy a new pump unless you are certain that it is the problem. The fuel system has fuses and relays that can fail and cause the pump not to run. Start by checking the fuses and accessing the fuel pump wiring harness to check for power.
Anyway here you go...
Slide both the driver and passenger seats all the way forward to give yourself as much room in the back seat as possible. (Luckily for me I have a vert so I dropped the top).
If your car has a ski pass remove the ski pass panel first and unhook the leather cover from the metal bar that goes across the ski pass opening.
Remove the rear seat lower cushion by lifting the front edge up, once it is unlatched pull torward the front of the car and set it aside.
on the passenger side you will now see a round rubber grommet with wires running to it, under here is the fuel pump access cover.
Pull forward the carpeting than pull back the rubber insulation to expose the access panel. (may need to slightly tear the insulation to get it started)
Loosen the four nuts on the access panel and remove the panel.
Now TEST the pump
Before going any further I would confirm that there is power to the pump and it isn't running.
While sitting as close to the fuel pump as you can have someone turn the key to run, if the pump is working you will hear it hum for a few seconds and of course if its not working you shouldn't hear anything besides some solenoids click and maybe the hydraulics prime up if you have a convertible.
Remove the wire harness by sliding the retaining clip toward the passenger side and pull up.
To test for power at the pump I used a digital volt meter and contacted the red and brown wires on the harness.
Turn the key to run and for a few seconds you should get a reading of 12.6v (my battery was weak from having the hazards on while I was broke down so I only got 12.29v) if you have another person to help they can turn the key forward as to start the car and this will keep a constant voltage running to the fuel pump, otherwise it will only get a few second prime from the run position (hope that made since). If you are not getting 12 volts to the pump you may want to look into the fuel pump relay or fuse for the problem. If you did get a 12v reading and when the pump was plugged in you couldn't hear it run, it would be safe to say your fuel pump is shot.
Fuel pump removal.
Unhook the negative battery cable.
Unhook the fuel line from the pump by squeezing the two clips and pull.
Now remove the retaining ring with either the special BMW tool or do what I did and use a hammer and screw driver. Place the screw driver tip on one of the notches of the ring and tap with a hammer, after a few hits move to the opposite side to prevent the ring from binding. After about a quarter turn it should get lose and easier to turn.
At this point put down some towels around the pump and grab a bucket to place the old pump into.
To remove the pump start by lifting strait up, there is a plastic hose you may need to manipulate a little to get past the tank. You will need to twist the pump 90 degrees and tilt it a little to keep the fuel gauge float arm from getting hung up inside the tank.
I recommend replacing the entire unit, fuel pump and gauge float. Its easier for one (don't have to swap pump from old assembly) and why not since your already in there. I bought the complete assembly from tischer for $225.
To install, First put the new rubber gasket around the new pump assembly but don't seat it around the top, fish the assembly half way into the tank. NOW seat the rubber gasket onto the gas tank and not the assembly. (makes life easier and less chance of pushing it into the tank)
Push the pump assembly down keeping the hose hookup in the same position as the old unit and line up the tabs at the rear.
Now hook up the fuel line and wire harness. Place the retaining ring back on and tighten it with the same method as removal and hook back up your battery.
Now Test.
Turn car to run, you should hear the pump run for a few seconds, I would cycle this a few times to be sure the pressure is built back up, now go ahead and fire it up. Hopefully all is good, bolt back down the access cover, fold down the rubber insulation, install seat cushions and done!
Hope this helps, it was super easy and hardly seems worth doing this DIY as it took longer to do than the fuel pump swap.
Peace
-Marty
Comment