Parts Catalog Accessories Catalog Tech Info Tech Forums
 
Follow Pelican Parts on Facebook Follow Pelican Parts on Twitter Follow Pelican Parts on Instagram Follow Pelican Parts on YouTube Follow Pelican Parts on Pinterest Follow Pelican Parts on Tumblr
  Search our site:    
View Recent Cars  |   Cart  | Project List | Order Status | Help    
 >  >
Fuel Injector Replacement
 
Bookmark and Share

Pelican Technical Article:

Fuel Injector Replacement

Nick Czerula

Time:

2 hours2 hrs

Tab:

$400

Talent:

*****

Tools:

Set of sockets (10mm, 13mm), flathead screwdriver

Applicable Models:

BMW Z3 Coupe/Conv (1996-02)

Parts Required:

Fuel Injectors, fuel injector O-rings,

Hot Tip:

Work with a cool engine and relieve fuel system pressure.

Performance Gain:

Clean and even flowing fuel injectors

Complementary Modification:

Replace with performance injectors

BMW Z3 models utilize a fuel injector per cylinder. Each fuel injector is an electrically controlled solenoid which, when triggered by a pulse from the engine control module (ECM), sprays a precisely metered amount of atomized fuel directly into the cylinder head intake port. The ECM supplies constant power to the injectors; the injector opening is controlled by the groundside of the circuit. Since fuel pressure at the injectors is (relatively) constant, the length of time (in milliseconds) of the grounding pulse from the ECM determines the amount of fuel injected. 

Over time fuel injectors can become restricted or fail electrically. If you have an injector giving you a problem, I suggest replacing them in sets. This way you maintain an even flow from all the injectors.

The injectors' shared fuel supply is a steel fuel rail. To remove an injector, you have to disconnect the electrical connectors to all the injectors, and then remove the fuel rail with all the injectors attached to it. Individual injectors are then separated from the fuel rail, as needed.

Be sure to relieve fuel system pressure before beginning. This will minimize the amount of fuel spilled. The best way to relieve fuel system pressure is to remove the fuel pump fuse and run the vehicle until the engine stalls. 

To avoid marring the paint and trim, work with a plastic prying tool or wrap a screwdriver tip with masking tape before prying out body or interior items.

Keep in mind that when your car was serviced before, parts may have been replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have, so be prepared with different size sockets and wrenches. 

Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If you're working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Do not work on your vehicle if you feel the task is beyond your ability. 

Vehicle models change and evolve, as they grow older, so the vehicle shown in our illustrations may vary slightly from yours. If something seems different, let us know and share your info to help other users. Do you have questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information.

Remove fuses #13 and #18 (check that this fuse applies to you vehicle).
Figure 1

Remove fuses #13 and #18 (check that this fuse applies to you vehicle). Use the fuse application chart located below your fuses to identify fuse number. Start and run engine until it stalls. Once engine stalls, attempt to start again, if it does not start, fuel system pressure has been relieved. Keep in mind; this does not remove all the fuel from the fuel lines, only the pressure. So you still need to be prepared to catch leaking fuel when fuel lines are disconnected. Disconnect negative (-) battery cable. See our tech article on Battery connection notes. Models with 4-cylinder engine Remove the upper intake manifold. See our tech article on intake manifold removing.

Models with 4-cylinder engine:

Remove the upper intake manifold. See our tech article on intake manifold removing.
First you will have to disconnect the fuel injector electrical connectors.
Figure 2

First you will have to disconnect the fuel injector electrical connectors. Good news in the 4-cylinder models it is much easier. There are four individual connectors you remove by pressing the wire retainer and pulling off.

It is almost impossible to fit a finger down next to the injector, what I suggest doing is use a flathead screwdriver to release the wire retainer, then pull up on the electrical connector.
Figure 3

It is almost impossible to fit a finger down next to the injector, what I suggest doing is use a flathead screwdriver to release the wire retainer, then pull up on the electrical connector.

Next you have to remove the fuel lines from the fuel rail.
Figure 4

Next you have to remove the fuel lines from the fuel rail. Loosen the two 12mm nuts (green arrows). Once loose, pull the line out of the fuel rail. Place a rag under the lines before you pull them out to catch the fuel that will leak out.

Then pull fuel rail straight up and out of intake manifold.
Figure 5

Then pull fuel rail straight up and out of intake manifold. Be careful not to damage a fuel injector when removing, these are air shrouded injectors and are more delicate that standard injectors. If O-rings are stuck, you can lightly pry the fuel rail up using a flathead screwdriver. I like to pry between the mounting point on the intake and the fuel rail. If you spray some soapy water (green arrow) at the base of the injectors, it will help when removing.

If needed, lever at the rear of the fuel rail also.
Figure 6

If needed, lever at the rear of the fuel rail also. Once the front is free, it may be necessary to do this. I like to lever between the edge of valve cover and fuel rail.

Once the fuel rail is removed, inspect the condition of the fuel line sealing O-rings (green arrows).
Figure 7

Once the fuel rail is removed, inspect the condition of the fuel line sealing O-rings (green arrows). Replace if needed.

To remove individual fuel injectors, start by removing the air line to the injector body.
Figure 8

To remove individual fuel injectors, start by removing the air line to the injector body. Pull it straight off the injector.

Then, remove retaining clip by sliding off fuel rail using a flathead screwdriver.
Figure 9

Then, remove retaining clip by sliding off fuel rail using a flathead screwdriver.

Then pull fuel injector straight out of fuel rail.
Figure 10

Then pull fuel injector straight out of fuel rail.

When reinstalling the fuel injectors into the fuel rail, be sure retaining clips are properly seated.
Figure 11

When reinstalling the fuel injectors into the fuel rail, be sure retaining clips are properly seated. Align the square slot with the tab on the injector. When reinstalling fuel injectors, replace sealing O-rings. Press fuel rail with injectors into intake manifold until fully seated. Then install fuel rail fasteners and tighten. Reassemble remaining items and check that there are no fuel leaks. 

Models with 6-cylinder engine:

Remove engine covers. See our tech article on removing engine covers. Some of the photos in this tech article are from a BMW with the same engine as Z3 models and will get you through the task of replacing your fuel injectors.
Working at top of intake manifold.
Figure 12

Working at top of intake manifold. Locate oxygen sensor connectors. (green arrows) Slide both connectors out of mounting bracket and lay aside. Not all models have the oxygen sensor connectors here, you may not have to disconnect them.

Working at center of intake manifold, disconnect intake air temperature sensor electrical connector by releasing tab and pulling off.
Figure 13

Working at center of intake manifold, disconnect intake air temperature sensor electrical connector by releasing tab and pulling off. (yellow arrow)

Working at intake VANOS solenoid, disconnect VANOS solenoid electrical connector by releasing tab and pulling off.
Figure 14

Working at intake VANOS solenoid, disconnect VANOS solenoid electrical connector by releasing tab and pulling off. (yellow arrow)

Then release fuel injector harness strip from fuel injectors and remove.
Figure 15

Then release fuel injector harness strip from fuel injectors and remove. I find the easiest way to do this is to use a flathead screwdriver and gently pry up at each fuel injector. This will release the spring clips that hold electrical harness to fuel injectors.

Work your way down injectors while disconnecting injector harness.
Figure 16

Work your way down injectors while disconnecting injector harness. Lay fuel injector harness aside.

Working at rear of intake manifold, disconnect fuel line by pressing release tab and pulling apart.
Figure 17

Working at rear of intake manifold, disconnect fuel line by pressing release tab and pulling apart. Have a rag handy to catch any dripping fuel. You will have to reach behind intake manifold, near firewall. (green arrow) You can see the line, but will have to do this part mostly by feel.

Reach behind intake manifold, locate fuel line (green arrow).
Figure 18

Reach behind intake manifold, locate fuel line (green arrow). Push fuel line toward fuel rail (purple arrow) then press release tab (yellow arrow) and slide fuel line off connection. Have a rag handy to catch any dripping fuel.

Next, remove four 10mm fuel rail fasteners (green arrows).
Figure 19

Next, remove four 10mm fuel rail fasteners (green arrows).

Then pull fuel rail straight up and out of intake manifold.
Figure 20

Then pull fuel rail straight up and out of intake manifold. Be careful not to damage a fuel injector when removing. If O-rings are stuck, you can lightly pry the fuel rail up using a flathead screwdriver. I like to lever between the edge of valve cover and fuel rail.

To remove individual fuel injectors, remove retaining clip (green arrow) by sliding off fuel rail using a flathead screwdriver.
Figure 21

To remove individual fuel injectors, remove retaining clip (green arrow) by sliding off fuel rail using a flathead screwdriver.

Then pull fuel injector straight out of fuel rail.
Figure 22

Then pull fuel injector straight out of fuel rail. When reinstalling fuel injectors, replace sealing O-rings and be sure retaining clips are properly seated. Press fuel rail with injectors into intake manifold until fully seated. Then install fuel rail fasteners and tighten. Reassemble remaining items and check that there are no fuel leaks.

Bookmark and Share
Comments and Suggestions:
Kman Comments: Any other ideas of why my z3 is smelling like gasoline on startups, this didn't fix the problem.
August 2, 2016
  Followup from the Pelican Staff: I would assume a fuel leak. Check the fuel tank and lines for signs of leaks. Follow the odor to the source. - Nick at Pelican Parts  

  Search our site:    

View Cart & CheckOut | Project List | Order Status |  Help    

 

[Home] [Customer Service] [Shopping Cart] [Privacy Statement]
 [Contact Us] [About Us] [Shipping] [Map to our Location] [Careers]

Copyright © Pelican Parts Inc.

Page last updated: Wed 12/7/2016 02:07:07 AM