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BMW E39 Fuel Rail Rebuild
 

Pelican Technical Article:

BMW E39 Fuel Rail Rebuild

Kerry Jonsson

Time:

4 hours4 hrs

Tab:

$50

Talent:

****

Tools:

Internal snap ring pliers, small pick

Applicable Models:

BMW 525i Sedan/Wagon (2001-03)
BMW 528i Sedan/Wagon (1997-00)
BMW 530i Sedan (2001-03)
BMW 540i Sedan/Wagon (1997-03)

Parts Required:

Fuel rail, fuel injector, fuel injector seals

Hot Tip:

Thoroughly drain the fuel rail before removing the injectors

Performance Gain:

Better running engine

Complementary Modification:

Replace fuel filter or pressure regulator as the same time

The job of your fuel injector is to supply fuel into the intake manifold pointed at each cylinder intake tract. The bottom end of the fuel injector sits in a port in the intake manifold. An O-ring is used to seal the area around the injector so air does not leak into the manifold. The top end of the injector is mounted in the fuel rail. Here fuel is fed into the top of the injector to pass through it and into the intake manifold. O-rings at the top of the injector keep the pressurized fuel from leaking past the injector. If either of these O-rings leak it will cause misfires and poor drivability. Also, on older systems with return lines the fuel pressure regulator is installed in the fuel rail. The fuel pump makes more pressure than the fuel system needs. The job of the regulator is to allow excess fuel pressure to leave the fuel rail and return to the fuel tank. This keeps the fuel pressure stable. In this tech article we are going to go over resealing the fuel rail and replacing the fuel pressure regulator.

You do have to remove the fuel rail from either the six or eight cylinder engines. See our tech articles on fuel rail removal before proceeding. Drain the fuel rail thoroughly before servicing it.

Fuel Rail Rebuild Six Cylinder:
Working at the back of the fuel rail use the internal snap ring pliers to remove the internal snap ring that holds the fuel pressure regulator in the rail.
Figure 1

Working at the back of the fuel rail use the internal snap ring pliers to remove the internal snap ring that holds the fuel pressure regulator in the rail.

With the snap ring removed pull the fuel pressure regulator out of the housing in the fuel rail.
Figure 2

With the snap ring removed pull the fuel pressure regulator out of the housing in the fuel rail. I do not recommend prying between the fuel and the regulator to remove it because the rail will bend easily.

Working at one of the injectors use a flathead screwdriver to remove the injector retaining clip.
Figure 3

Working at one of the injectors use a flathead screwdriver to remove the injector retaining clip.

Twist and pull on the injector at the same time to remove the injector from the rail.
Figure 4

Twist and pull on the injector at the same time to remove the injector from the rail.

With a sharp pick lever on the inside of the O-ring at the top of the injector and pull the O-ring off of the injector.
Figure 5

With a sharp pick lever on the inside of the O-ring at the top of the injector and pull the O-ring off of the injector.

Working at the bottom of the injector use a sharp pick to lever off the lower O-ring.
Figure 6

Working at the bottom of the injector use a sharp pick to lever off the lower O-ring. Installation is the reverse of the removal procedure. Install the correct O-ring on both the bottom and the top of the injector. Fit the injector in the fuel rail and install the retaining clip in the slots on the fuel rail and the injector. Do this for each injector you removed. Fit the fuel pressure regulator in the fuel rail and install the internal snap ring. Install the fuel rail on the engine and cycle the key several times to build up fuel pressure and check for any fuel leaks before starting the engine.

Fuel Rail Rebuild Eight Cylinder Engine:
Working at the right side of the fuel rail use internal snap ring pliers to remove the internal snap ring that holds in the fuel pressure regulator.
Figure 7

Working at the right side of the fuel rail use internal snap ring pliers to remove the internal snap ring that holds in the fuel pressure regulator.

With the snap ring removed pull the fuel pressure regulator out of the housing in the fuel rail.
Figure 8

With the snap ring removed pull the fuel pressure regulator out of the housing in the fuel rail. I do not recommend prying between the fuel and the regulator to remove it because the rail will bend easily.

Moving to one of the injectors use a flathead screwdriver to lever off the injector retaining clip.
Figure 9

Moving to one of the injectors use a flathead screwdriver to lever off the injector retaining clip.

Twist the injector while pulling it out of the fuel rail to remove it.
Figure 10

Twist the injector while pulling it out of the fuel rail to remove it.

With a sharp pick lever on the inside of the O-ring at the top of the injector and pull the O-ring off of the injector.
Figure 11

With a sharp pick lever on the inside of the O-ring at the top of the injector and pull the O-ring off of the injector.

Working at the bottom of the injector use a sharp pick to lever off the lower O-ring.
Figure 12

Working at the bottom of the injector use a sharp pick to lever off the lower O-ring. Installation is the reverse of the removal procedures. Install the correct O-ring on the bottom and top of the fuel injectors. Fit the injector into the fuel rail and apply the injector retaining clips. Make sure the retaining clip slides into the slots of both the fuel rail and the injectors. Fit the fuel pressure regulator and install the internal snap ring in the fuel rail. Install the fuel rail and lines on the intake manifold. Cycle the ignition key a few times to build fuel pressure and check for fuel leaks before starting the engine.

Comments and Suggestions:
Uneek 18 Comments: Oops my car is a 2001 530i BMW
January 20, 2018
  Followup from the Pelican Staff: got it. - Nick at Pelican Parts  
Uneek 18 Comments: Was smelling strong order of gas. When checking what problem could be. Saw that my injectors were leaking except second one from the radiator it was shooting the gas out. Changed out the O rings and injectors . 5 r great but that #2 isn't shooting the gas out but it's still running out. Looks like it coming from the fuel rail. Could that fuel rail be bad? And do u have to replace the whole rail or can u repair it?
January 20, 2018
  Followup from the Pelican Staff: The rail could have pinhole in it. You will have to replace it. Give The Pelican Parts parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need.
- Nick at Pelican Parts
 
Norm Comments: OOPs - my car is a 1999 540i E39 M62. It sat for 18 months before I started the repair project. also needed a water pump & AC compressor Maybe I let water accumulate in the gas tank nearly empty and I leave in a humid climate on the West Coast of Canada NOTE: gas lines were disconnected and partially drained for the timing chain project.
January 11, 2018
  Followup from the Pelican Staff: Got it, thanks. Answered you at your other post. - Nick at Pelican Parts  
Norm Comments: Trouble restarting after timing chain/guides replacement.

Also replaced coils, injectors, plugs, ccv, and mass airflow sensor.
Car started after 10-15 seconds, initially ran rough but started to smooth out. Battery was dead, so car stalled when booster cables removed. Gas warning light was on,so filled to 1/2 tank.
Now it cranks still on booster cables but won't start.
Suggestions?
January 11, 2018
  Followup from the Pelican Staff: When your engine doesn’t start you’ll want to check the basics. Check spark, fuel injector pulse and fuel pressure, volume, quality and engine compression. Are there any fault codes? Once you figure out what is missing, it will be easier to diagnose.

My gut tell me compression will be your issue. - Nick at Pelican Parts
 
Drinkingsnake Comments: Oups ...!!...i Forget this info ...Sorry sir !!
My car is 1998 BMW 740 i M62 4,4 L
Thanks for your previous reply

Chris , from France
July 21, 2017
  Followup from the Pelican Staff: No sweat. Thanks for the note. - Nick at Pelican Parts  
drinkingsnake Comments: Hy,
after new fuel injector fitting, do we need to "code" them with an ODB scan tool ?!?
Thanks,
Chris from France
July 19, 2017
  Followup from the Pelican Staff: On what vehicle year, model and engine? - Nick at Pelican Parts  
Meguinnes Comments: What the vacuum hose from the fuel regulator to the ccv does?
Thanx
June 26, 2017
  Followup from the Pelican Staff: Supply vacuum to determine regulator function. - Nick at Pelican Parts  
Sroor9001 Comments: Thanks for information ;
May 6, 2016
  Followup from the Pelican Staff: No problem. - Nick at Pelican Parts  
Sroor9001 Comments: Hello friend
Good writing
Just want to know what's the diameter size of the hose going to fuel railway cause I want to cut that hose and put inline fuel gauge so I know fuel pressure without need to test pressure in case of failing fuel pump or fuel pressure regulator
My car is 525 e39 model 2002
May 3, 2016
  Followup from the Pelican Staff: Give our parts specialists a call at 1-310-626-8765

I don’t have that info. - Nick at Pelican Parts
 
Chango Comments: What's the difference from a fuel injector rail on a 99 bmw528i and the the rail from 97
August 8, 2014
  Followup from the Pelican Staff: They could be the same, could be different. I would need the last seven digits of the VIn of each vehicle the parts are from to know. - Nick at Pelican Parts  

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Page last updated: Tue 2/20/2018 02:07:27 AM