Pelican Technical Article: Fuel Pump Replacement Wayne R. Dempsey
Time: 2 hrs
Tab: $300
Talent:
Tools:
Oil filter wrench, battery charger
Applicable Models:
986 Boxster (1997-04) 987 Boxster (2005-08)
Parts Required:
Fuel pump, o-ring, sending unit
Hot Tip:
Jumper the relay to empty the tank
Performance Gain:
More reliable fuel system
Complementary Modification:
Replace battery
This article is one in a series that have been released in conjunction with Wayne's new book, 101 Performance Projects for Your Porsche Boxster. The book contains 312 pages of full color projects detailing everything from performance mods to changing your brake pads. With more than 950+ full-color glossy photos accompanying extensive step-by-step procedures, this book is required reading in any Boxster owner's collection. The book is currently available and in stock now. See The Official Book Website for more details.
Check out some other sample projects from the book:
Some common fuel injection problems can be traced back to a faulty or non-operational fuel pump. If your pump is noisy and loud, or the fuel pressure in the engine compartment is below what is needed for proper fuel injection operation, then it's probably time to replace it. The fuel pump is a not as simple a device as one might think. The fuel actually runs through the pump and acts as a coolant and lubricant for the entire assembly. Therefore, if you let your car run out of gas, make sure that you turn off the pump immediately, or you might damage the internal components of the pump. Trust me - not much is worse than a broken or faulty pump leaving you stranded on the side of the road.
Typical fuel pump problems can sometimes be headed off in advance. If the pump is noisy, and making loud clicking noises, then chances are that the bearings inside are worn and should be replaced. If the pump continues to make noise even after the ignition is shut off, internal check-valves in the pump may be showing signs of failure. The pump could seize up at some time, or the pressure to the fuel injection system could drop. Either way, the car will not be performing at its peak. Another symptom of failure is the pump getting stuck, and then finally kicking in after turning the ignition on and off a couple of times. This could be a clear sign that you are living on borrowed time, and that you should replace the pump immediately. Check the electrical connections to the pump before you replace it to make sure that it's not an electrical problem.
The first step in replacement is to prep the car. Remove as much gasoline out of the car as possible (see photos). Some warnings too:
Always have a fire extinguisher handy in case an emergency arises.
Gasoline is highly flammable. When working around fuel and fuel line connections, don't disconnect any wires or electrical connections that may cause electrical sparks.
Always remove the gas cap to relieve any pressure in the tank prior to working on the fuel system.
Do not use a work lamp when working near fuel or fuel tanks. If you need some light, use a cool fluorescent lamp and keep it far away from the pump.
Gasoline vapors are strong, harmful, and can cause you to become drowsy and not think straight. Always perform work in a well-ventilated area with plenty of fresh air blowing through.
Always disconnect the battery when working on the fuel system. Leave it disconnected for at least 30 minutes to allow any residual electrical charge in components to dissipate.
Keep plenty of paper towels on hand, and wear rubber gloves to prevent spilling gasoline on your hands
Be well grounded - don't do anything that will create static electricity. Keep all cell phones and pagers a safe distance away.
Run the car so that the gas tank is near empty, and then remove the remaining fuel as detailed in Figure 1
The first step is to remove the battery from the car (see Pelican Technical Article: Battery Disconnect Switch / Battery Buddy Installation). The lower battery tray acts as both a retaining platform for the battery and a cover for the fuel pump area. Underneath this tray, you will see the top of the fuel tank sending unit. Disconnect the connector that mates with the sender. Now, squeeze and disconnect the fuel lines & breather hose that feed into the top of the unit. There might be some small gas spillage here - have a roll of absorbent paper towels on hand. You might want to find an old pen to carefully plug the lines to prevent further leaks. If there is any fuel in your tank, now would be an excellent time to empty it (see Figure 1 and Figure 2).
The sender is held in place by the big circular disc with the risers on it. There is a special tool that is used to remove and tighten this black plastic ring. However, with a large flathead screwdriver or chisel and a small hammer, you can easily tap the plastic ring loose. Carefully remove the ring from the top of the sender.
Now comes the fun part. Make sure that you are prepared at this stage, with a heavily ventilated garage, plenty of paper towels, and rubber gloves. Pull up on the top of the sender, and the entire assembly should come right out of the tank (Figure 3). There is a big, thick o-ring that seals the pump to the tank: grab it and put it off to the side. See Photo 4 and Photo 5 for instructions on removal of the pump.
When reinstalling the pump into the car, make sure that the fuel hoses inside the tank don't interfere with the proper operation of the fuel tank sender. I found that my sender was getting stuck and the problem was the hoses. The solution was to open the tank up again, and zip tie the hoses out of the way. I would verify that they don't interfere with the movement of the sender before you button everything back up.
I recommend that you replace the large sealing ring with a new one. If you do opt to reuse the old one, and it doesn't seal well, you might be plagued with a fuel smell in the car from that point on. Make sure that the big o-ring is properly sealed around the outside of the pump and will seal with the opening of the tank. Spin on the large circular ring and use the hammer/screwdriver tapping procedure to tighten it. I tightened mine about as tight as I could get it without feeling that I would break the ring. Reconnect the fuel hoses and the electrical connector.
Reinstall and connect the battery after all fumes have subsided. Then crank the car over and see if it starts. If the car starts and runs for any length of time then the pump is working fine.
Figure 1
This photo shows a safe method for emptying the gas out of the tank in your Boxster. Disconnect the pressure side hose from the top of the pump and connect some clear plastic tubing to the barb (yellow arrow). Carefully connect the car's battery terminals up to a 12-volt supply, making sure that you wrap and insulate both terminals carefully. Jumper the relay in the driver's side foot well, (see Figure 2), turn on the ignition, and the pump should turn on and begin to pump fuel into your tank. Watch the level carefully, and shut the pump off when the external tank fills up, or when the Boxster's fuel tank runs dry.
This photo shows the relay panel under the driver's side foot well. The fuel pump is not normally turned on unless the engine is running, but you can remove the relay and bypass it using a simple jumper wire as shown here. Remove the fuel pump relay (shown in the inset) and then jumper pins 30 and 87 (typically labeled 3 and 5 on the relay panel). This will cause the fuel pump to turn on automatically when you turn the key in the ignition.
Once you remove the battery and the lower tray/cover, you will see the top of the tank and the fuel sender. Squeeze the fuel line connectors and remove them along with the vent hose and the electrical connections (lower left). Use a large chisel and a medium-sized hammer to carefully tap on the outer ring that holds the fuel pump in place (upper left). It should turn and loosen up with a few taps. With the ring loose, pull out the fuel tank sending unit, and you should be able to carefully squeeze and remove the fuel supply hoses that attach to the bottom. When you reinstall the sending unit, be sure to line up the big arrow (blue arrow) with the three lines on the tank (green arrow).
The upper left inset shows the fuel pump sitting inside the empty fuel tank. I had a really difficult time removing the pump from the bottom of the tank. Supposedly you should be able to simply turn it with your hands and unlock it from the bottom, but my grip wasn't strong enough. Instead, I used a rubber oil-filter wrench to carefully wrap around the circumference of the pump. One solid twist of the tool, and the pump came free of its locking site on the bottom of the tank.
Installation is pretty straightforward. A- The red arrow shows the circular locking ring that the bottom of the fuel pump snaps into with a twist. This secures the pump to the bottom of the fuel tank. B- Shown here is the new pump installed. It looks slightly different than the original, but it's functionally equivalent. C- With the new pump in place, install the fuel tank sending unit into the top of the tank. Be sure to connect the hoses from the pump to the bottom of the unit. D- Shown here is the new pump installed with the new sending unit all buttoned up and ready for testing. Be sure to put some fuel back into the tank prior to starting the fuel pump up.
Comments: I have a 2001 Porsche Boxster, the gas station fuel pump shuts off after a couple gallons. I think the fuel lines need tied up, from what Ive been reading. do you have an article on how to wire tie them up? Thanks Prisonbob
April 15, 2012
JS
Comments: Easy to follow the directions provided here, sucessful with no drama, saved $390 labor at the dealer.
For those wanting to survey the symptoms, after a 30 minute drive we stopped, were out of the car about 10-15 minutes. The car would start run for about 10 seconds and then die out. This was repeatable. After an overnight to sit, the car wouldn't replicate and started no problem. This didn't last, once a drive took place it was back to not running.
Did buy the new relay $12 here, but it didn't change anything but for $12 it was worth a try-it would have been great if it had. The fuel pump also has a 30 amp fuse in the drivers footwell,good to check it before anything else. In my case, it was fine.
Buy a good hand pump, a $12 dollar syphon pump moved 8 gallons pretty rapidly. Great article -thanks as always.
March 31, 2012
Tee
Comments: I have a 2003 3.2s and the top of the sender unit only has 2 fuel connection hoses. I have bridged the relay termimals and had the pump running but no fuel comes out either of the hoses, Can you help
March 25, 2012
JT
Comments: Hi Chaps, my 1998 996 cut out without warning, through viewing various forum sites, including this one, I ordered a new fuel pump relay, sorted, it took seconds to fit, it,s located under the foot pedals above the fuse box. But where the tell tale signs there? A couple of days prior to the relay failing, the car felt a little juddery one morning on the way to work, I also switched off the airconditiong and the revs dropped rather than increased. Defiantly worth trying the relay first before concluding it could be the fuel pump. Hope this helps some of you guys.
March 17, 2012
Sir Laffalot
Comments: I don't see where you mentioned the size of the hose that one needs to drain the gas tank: 1/4-inch I.D. polyethylene tubing. It's not clear which makes it hard to see when gas goes into the line, but it's fuel-resistant. Regular clear vinyl will work too, I guess, but it might work next time.
December 2, 2011
Followup from the Pelican Staff: The clear vinyl hose works fine for short term emptying of the fuel tank like this - it's not going to eat through or dissolve the hose while your emptying the tank. I wouldn't use it long term, but for short term usage like this, the clear hose works well. - Wayne at Pelican Parts
Charz
Comments: I have a question about Figure 2 in the Fuel pump replacement DIY. The write up says jumper pins 30 and 87 but the picture shows pins 85 and 86 jumpered. Also, if jumpering it does not run the pump with the key on, can you supply 12v to the pump while its in the car to test it? If so, which pins on top of the pump do you use, there are 4.
June 20, 2011
Followup from the Pelican Staff: I'm pretty sure that in the photo, it's an optical illusion based upon the relay socket. The socket has six slots, I believe, and the relay only appears to have four. So, I believe the proper ones are indeed jumpered. You can indeed supply 12V directly to the pump, but this isn't the safest approach in my opinion, because you can have spark in that area while you're pumping out fuel. Two wires in the top are for the pump power, and two are for the fuel sender. Sorry, I'm not sure which one is which, you'd have to take the pump out and trace them from the connector. Or, disconnect the connector, jump the wires at the relay, and then test the connections with a multimeter. But, if you're going to do that, you might as well just use the jumper to power the pump. - Wayne at Pelican Parts
Kepakurl
Comments: Hi My 986 boxster 2002 stopped on the side of the road with no warning.It had run out of fuel with 15 litres still in the tank. Runs fine otherwise. Is this the fuel pump.The guage is working fine.
October 18, 2010
Followup from the Pelican Staff: Indeed, the fuel pump is probably the first thing that I would check and/or replace. You might also want to check the fuel pump relay and/or the fuse on the pump circuit as well prior to replacing the pump. - Wayne at Pelican Parts
Check out some other sample projects from the book:
