No announcement yet.

Replacement Fuel Injectors - How To and Pics

  • Filter
  • Time
  • Show
Clear All
new posts

  • Replacement Fuel Injectors - How To and Pics

    Hey, everyone,

    Over the long weekend, I replaced my fuel filter and injectors. Replacing the filter was easy enough: it’s located in front of the left rear tire, and took maybe 10 minutes. I used the instructions in the 101 Projects book. However, replacing the injectors was a more involved procedure, and the book did not help me much. I used re-manufactured injectors from Pelican Parts, and so far, they work just fine. Here are some pics and how I did it. This is my first how-to, so go easy on me, gents.

    1) Disconnect the battery and open the hood. Standing on the driver’s (left) side, locate the fuel rail and the two bolts holding it in; remove them with a 10mm socket. Remove the electrical connector by prying gently with a small flathead screwdriver.

    2) I held the throttle out of the way by jamming a rubber-coated handled toothbrush in there, holding it open and out the way of the fuel rail. I did not disconnect the throttle cables.

    3) Pull up on the fuel rail/electrical rail combo slowly but firmly, and pop the injectors out of the manifold. The fuel rail and the electrical rail are held together by the four injectors, making a Y shape.

    4) Undoing the electrical rail from the injectors was the toughest part for me. Using a flathead screwdriver, start by prying the electrical connector off of the injector closest to the front of the car (identified by #1 in the picture above). Work your way toward #4 by prying off the connectors. Then you can swing the electrical rail up, leaving the four injectors still plugged into the fuel rail.

    5) Pull the injectors out of the fuel rail. Wipe everything down, as gasoline will have spilled out and around by this point. I used a small amount of lithium grease around the o-rings, and installed the new injectors into the fuel rail, aligning the electrical connectors toward where they will click back into the electrical rail.

    Guess which one is the NEW one!

    6) Push the combo of the fuel rail and four injectors back into the manifold, and press firmly down, seating it into the manifold. Then carefully push the electrical rail back into the four injectors. They will install with a satisfying ‘click.’ Reinstall the two 10mm bolts and the electrical connector. Re-connect the battery and do a tool check. Don’t forget that big pink toothbrush, either. My car started right up after all this, only requiring a few cranks on the ignition key to re-pressurize the fuel system’s new filter and injectors.


  • #2
    Nice write up! Will be quite helpful when I get home and change mine.


    • #3
      Thank you for this....this helped a lot!!!!


      • #4
        Definitely appreciate the effort. We need more folks to document their experiences - myself included. I keep trying to find the time to document my A/C system refurb experience.
        Alles Beste!

        B. Wheaton
        1989 E30 M3, Owner since June 2000
        2008 E61 535xiT - The DD and work horse

        Register your E30 M3!


        • #5
          Great write up, thanks!

          I agree more of us need to do things like this. I find myself getting lazy...sometimes documenting what I am doing seems like way more work than the job itself.


          • #6
            I agree, I should have documented the Low speed fan troubleshooting I've done in addition, letting fellow M3 nuts that there the fan resistor can be replaced (having enough room to solder and heat shrink) with the fan in place. The only thing that needs to be removed is the front grill.


            • #7
              Thanks for details - was helpful in removing injectors for servicing. I also removed lower line from Fuel Pressure Regulator to help get to the injectors.

              They did take a bit of pulling to get out of the rail. Though I spilled a small amount of fuel when they were removed from each injector, I couldn't see how to avoid this?
              One letter. One number. One legend ///M3.


              • #8
                I wish this whole procedure was around a few months ago when I took mine apart.

                This is what I did to get rid of all the fuel in the rail and on the lower line.
                I know it's REDNECK but it worked.

                1. remove the appropriate fuse to the fuel pump and run car until it starves and stalls.

                2. Open Gas Cap and then use some compressed air through the front of the fuel rail
                after taking off the small return hose (attached to pressure regulator ) to push the fuel back into the tank.
                (Make sure you open the gas cap as if you don't you will build up air pressure in the tank
                and it will reverse push back all the gas through your lower hose and rail. Not a good thing and possibly
                dangerous. Don't ask me how I know)

                Also don't forget to change the O rings where the fuel rail joins the pressure regulator.
                It's the same size as the injector O rings. Ask the cleaner to give you a few extra.

                1989 E30 M3
                1984 Renault R5 Turbo 2
                2001 Renault Clio Sport V6
                1999 Skyline R34 GTR VSpec
                1972 Datsun 510 KA24 DE - Sold
                1968 Shelby Mustang GT 350 Convertible - Sold


                • #9
                  Anyone know if the injector o-rings are the same top and bottom?
                  Real OEM shows them as 7,52X3,53, but it only specifies the bottom. I have an injector weeping from the top where it meets the fuel rail and I want to have one on hand before I pull it.


                  • #10
                    Mick, I am 98% sure they are the same.
                    Put it this way I always use new rings and I have never ordered 2 part numbers,,, however that doesnt mean im not doing it wrong LOL.
                    jimmy p.
                    87 E30 M3 Prodrive British Touring Car
                    88 E30 M3 Zinnoberot - Street
                    88 E30 M3 Lachsilber - Race (#98 SCCA SPU)
                    92 E30 M Technic Cabrio - S14 POWERED!
                    98 318Ti M44, Base - Morea Green
                    04 Ford F350 - V10


                    • #11
                      I used the same o-rings for the top and bottom, and I don't have any leaks.


                      • #12
                        Well done !

                        I bought the exact same injectors for my runs very well with them. I installed them in 2018 and they improved my fuel consumption.


                        • #13
                          Thanks for putting in the effort to post your How-to.
                          Personally I would use some petroleum jelly or a drop of engine oil to lubricate the o-rings as both are easier to remove/wipe away than lithium grease after having fitted the injectors.


                          • #14
                            Great thread! I followed this and replaced my injectors, very easy to do. Car is running great but now the tach is a bit jerky and looks as if it gets hung up at certain rpms for a second. Car feels smooth so could I have hit the tach wire somehow or any other ideas?

                            EDIT: Did a search and sounds like my SI board batteries are acting up. Amazing that all was fine there but of course as soon as I eliminate one issue (replacing fuel injectors) with a positive result a new issue emerges. Any chance this is because I disconnected the battery to do the FI swap and the SI batteries just need to charge up?


                            • #15
                              Tach operates perfectly now, SI batteries just needed to recharge I reckon. I'd like to now get the previous injectors rebuilt to EVO 2.5 spec, any recommendations on who to send them to?