Changing the Fuel Filter on a 3000GT

• Why Do I Want To Do This?

  • Fuel filters, like any filter, eventually get clogged and their throughput decreases. A clogged fuel filter can, among other things, cause your engine to run lean, to get bad gas mileage, or to have lower power output.



• How Often Should I Do This?

  • The Service Manual doesn't seem to mention a replacement interval, but a good rule of thumb is to replace it every 60,000 miles, or 30,000 miles if you're obsessive about your car. Using low-quality gas will decrease the life of your filter, as will contaiminants in your fuel tank. If you have either of those conditions, replace your filter more often.



• How Long Will It Take Me To Do This?

  • For your first time, plan on a couple hours to a half day, depending on how mechanically inclined you are and how many beer breaks you take. After you've done it once, you should be able to complete the filter change in 1 hour if you're taking you time, and about 30-45 minutes if you're in a hurry.



• Anything I Should Do Prior To Attempting This Procedure?

  • Make sure you have all the parts and tools you'll need.
  • If you have the stock stereo, make sure you have the security code for the stereo because you'll have the battery disconnected for long enough to engage the anti-theft code.



• What Mitsubishi Parts Will I Need?

  • (1) New Fuel Filter (MB658136 - $25.00ea)
  • (4) Fuel Line Gaskets (MF660064 - $0.25ea) [optional]



• What Other Parts Will I Need?

  • None



• What Tools May/Will I Need?

  • (2) 19mm Combination Wrenches (3/4" will also work)
    *Note* The open end on some wrenches may be too thick to fit around the neck of the fuel filter - my Craftsman wrenches were like this. I used another 19mm wrench (no-name brand) that was thinner for this job.
  • (1) 14mm Flare-nut Wrench [optional]
  • (1) 12mm Wrench or Socket (3/8" Drive)
  • (1) 10mm Wrench or Socket (1/4" or 3/8" Drive)
  • (1) 8mm Wrench or Socket (1/4" or 3/8" Drive)
  • (1) 3/8" Drive 6" [or longer] Extension
  • (1) 3/8" Drive Socket Wrench (or Air Ratchet)
  • (1) 1/4" Socket Wrench (or Air Ratchet) [optional]
  • (1) Phillps #2 Screwdriver
  • Shop Towels
  • Safety Goggles
  • Latex Gloves

The 3000GT Fuel Filter

Your mission, should you choose to accept it, is to locate the elusive 3000GT/Stealth fuel filter (right), disconnect and remove it from the vehicle, and install a replacement filter. You should not be particularly fond of the skin on your knuckles, as you will most likely lose some of it.

The fuel filter, when disassembled, looks like the picture on the right. Note that the parts you will be turning to remove the fuel lines are the gold-colored bolts, NOT the neck (black) of the fuel filter itself

The Procedure

	Remove the Spare Tire
	Unscrew the bolt that holds it in the center.
	Remove the Passenger Side Cargo Tray
	There are three black screws that hold the plastic tray to the trunk floor.
	Remove the Fuel Pump Access Panel
	Remove the four screws that hold the fuel pump access panel to the trunk floor. If you've never done this before or if you live in an area that uses salt on the roads, these screws may be rather hard to loosen. Be careful not to strip them.
	Disconnect the Fuel Pump Wiring Harness
	Squeeze the tab and pull it off. The idea here is that by disconnecting the power to the fuel pump and trying to start the car, the injectors will bleed out the fuel in the rails and feed lines until there is little or no pressure in the lines. This makes it safer to disconnect these high-pressure fittings.
	Start the Engine
	If it turns over, it will die within a few seconds as it runs out of fuel. If the car hasn't been started in a while, it may not turn over at all. In this case, just crank it with the starter for about 10 seconds and call it good.
	Reconnect the Fuel Pump Wiring Harness
	You should feel a click when it's securely attached.
	Reinstall the Fuel Pump Access Panel
	Same four screws.
	Reinstall the Passenger Side Cargo Tray
	Almost done in the trunk...
	Reinstall the Spare Tire
	Good time to check the pressure in the spare - it should be 60psi.
	Remove the Battery Terminal Connections, Battery Tie-down Bar, and Battery
	Disconnect the negative and positive terminals from the battery posts. ALWAYS, ALWAYS, ALWAYS, disconnect the negative terminal first!!! I have a socket wrench from when I was 16 that has part of the frame of my first car WELDED to it because I didn't know to take the negative terminal off first. Lots of sparks, battery on fire, and other bad things. But I digress... remember that when the negative terminal is connected, the ENTIRE chassis of your car (including all the metal parts) is one big GROUND. The stock terminals use 8mm nuts; I have an aftermarket negative terminal on my car that uses convenient wing-nuts. A couple of bucks well spent. Using a 10mm wrench or socket, completely remove the battery tie-down bar so that the battery can be removed. Carefully lift the battery out of the car and place it in a safe place out of the way.
	Remove Battery Tray and Washer Fluid Reservior
	Remove the four 12mm bolts at the corners of the battery tray so that you can lift it out of the way. You may leave the two more central bolts attached as they attach the washer fluid reservoir to the battery tray. As you will see, the washer fluid reservoir has hoses and a wiring harness attached to it, so if you want to save some time, simply place the washer fluid reservoir and battery tray assembly out of the way, but leave the hoses attached. Be careful not to scratch the paint on your fender if you do this!
	[optional] Remove Battery Tray Bracket
	At this point, you can remove the bracket that supports the battery tray if you'd like some extra room. There are two 12mm bolts along the bottom if you decide to remove it.
	[optional] Remove Intake Pipe
	*Updated 06/16/03* I'll leave this step here for documentation, but having done this a few more times now on different cars, you probably don't need to do this. My recommendation is to attempt the job without this step and only do this if you find you need the extra space. You will now be able to see the fuel filter on the firewall behind where the battery was. You may be able to change the fuel filter without this step, but you'll probably value any extra working space you can get! You only need to remove the portion of the pipe that extends from the throttle body to the first joint (near the MAS). The stock hose clamps use 10mm bolts. For turbo cars, you'd be removing the y-pipe instead of the pictured pipe. Be sure to remove the breather hose when you remove the pipe (it's the little 3/8" ID hose that goes from the rear valve cover to the nipple on the intake pipe).
	Remove Lower Fuel Pipe Connection
	The service manual says to remove the "U" shaped pipe that turns the fuel line around when it leaves the filter(toward the front of the car) and heads back toward the main fuel line. I could not loosen that fitting for the life of me. I ended up removing the bottom bolt on the fuel filter without removing the pipe, just had to be careful not to lose the gaskets. Updated 06/16/03: On my new VR-4 I actually had problems getting the lower fuel filter fitting off, so I used a flare nut wrench (line wrench) on the fitting on the "U-pipe" and I managed to get it off. I'll check the size next time I'm in there, but I think it was a 14mm flare fitting. Thanks to Kris Hartwell for this suggestion! Have your safety goggles on at this point, and place some shop towels around/below the filter so that any gasoline that sprays/leaks out will not go everywhere. Also, if you've never changed your fuel filter before, you may want to remove the upper connection first so you can see which parts move and which parts don't move. You'll be turning the bolt in the top of the filter, NOT the black neck of the filter! This is where the fun starts! Be sure you're turning the bolt the correct way (remember, it's upside down). You'll need two wrenches (19mm or 3/4") If you don't have two of the same wrenches, a 19mm and a 3/4" will work. Use the closed end on the bolt and grab the neck of the fuel filter with the open end of the other wrench. There's no room for a breaker bar in there, so you make sure you ate your Wheaties this morning. You will probably bleed after this step... and don't lose those 2 metal gaskets that go around the fuel connection! Installation Tip: Instead of lining up the wrenches the way I show them in the picture, use a 12-pt closed-end wrench and place it so that the wrench sticks out to the right (looking from above) of the wrench that is on the neck of the fuel filter. Then you can just grab both wrenches with both hands and squeeze to break the bolt free. Again, thanks to Kris for this tip!
	Remove Upper Fuel Pipe Connection
	When you've made it this far, it's all downhill from here. Thankfully, the upper connection is much easier than the lower one! Remove the upper fuel connection the same way you did the lower one, and remember those gaskets! You can optionally use a 19mm socket on the upper banjo bolt if that makes it easier for you to remove it.
	Remove the Fuel Filter
	Remove the two 12mm bolts that hold the fuel filter bracket to the firewall. After they are removed, the you will be able to remove the filter (finally!)
	Disassemble the Fuel Filter Bracket
	Remove the bolts, metal sleeves, and rubber spacers from the old fuel filter bracket as you will need to reuse them when you install the new fuel filter.
	Assemble the New Fuel Filter and Bracket
	Reassemble the same way you took the old one apart.
	Install the New Fuel Filter
	Bolt it to the firewall with the two 12mm bolts.
	Connect Upper Fuel Pipe Fitting
	Thread the banjo bolt (a.k.a. eye bolt) through the fuel line fitting and into the new fuel filter. Turn the opposite way from what is shown in the picture (picture is for removal). Make sure you put the metal gaskets on both sides of the fuel line fitting. I think you can technically reuse these gaskets, but since they're cheap, I usually just replace them. The torque spec is 22 ft*lbs (30N*m), and you should be able to get a torque wrench on this fitting if you choose to use one.
	Attach Lower Fuel Pipe Connection
	Much the same as the upper connection, except that I don't think there's any way you're getting a torque wrench in there. You'll have to guestimate based on your prior experience. Again, turn the opposite way from what is shown in the picture (picture is for removal).
	[optional] Reinstall Intake Pipe
	Only if you removed it...
	[optional] Reinstall Battery Tray Bracket
	Only if you removed it...
	Reinstall Battery Tray and Washer Fluid Reservior
	It should just drop right back in. Make sure you reattach the water hoses and sensor wiring harness if you removed them.
	Reinstall the Battery Terminal Connections, Battery Tie-down Bar, and Battery
	Just reverse the way you took them off. Make sure you attach the positive terminal of the battery first.
	Clean Up Any Mess You Made
	Make sure you wipe up any gasoline that dripped under the car.
	Start the Car
	It may take a few seconds of cranking due to the lack of fuel pressure, but she should fire right up.
	Check For Fuel Leaks
	Use your eyes, ears, and nose (preferably not your fingers) to check out the area around the fuel filter to ensure you have no leaks. The fuel system should maintain about 30psi if you shut it down while idling - that should be enough pressure to make an audible hissing if there is a leak. If you did everything right, there is no leak. Go drive your car.