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DIY - Replacing fuel injectors on a MKIV 12v VR6

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DIY - Replacing fuel injectors on a MKIV 12vVR6

REPLACING FUEL INJECTORS ON A MKIV 12V VR6The following procedure describes how to remove (and replace) the fuel injectors on aMKIV 12v VR6, one of which is shown below.

Poorly operating injectors can cause decreased gas mileage, rough idle, decreasedengine power, engine surging and increased emissions. Sometimes the CEL will evencome on, causing you to fail an OBDII emissions test. I removed my injectors becausethe fuel trim values reported by VAG-COM indicated that my engine was running closeto 10% lean at elevated engine speeds (10% is the limit for triggering a CEL). Since theinjectors had more than 216k miles on them, it was possible that the injectors had

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Mar 8th, 200216,088

VgRt6

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12-12-2006 07:05 PM #1

VWVortex.com - DIY - Replacing fuel injectors on a MKIV 12v VR6 http://forums.vwvortex.com/showthread.php?2975414-DIY-Replacing-fu...

1 of 22 1/12/2012 2:31 AM

become clogged by fuel deposits over time and the ECU was compensating for thedecreased flow rate by increasing the injector pulse duration. I sent the removedinjectors to WitchHunter Performance for ultrasonic cleaning and replacement of filterbaskets and o-rings. The results of this cleaning procedure are documented HERE.

The procedure below is based on a '99.5 Jetta GLS VR6, but should be applicable to allMKIV VR6s and similar on many later model VWs.

The following items are required to perform the procedure:

- Small screwdriver- 5mm hex wrench or socket- Spring clip pliers (regular pliers will work fine)- Two rods ~ 5/16" in diameter, if you want to plug the fuel lines (I used a screwdriverand 1/4" socket extension)- Roll of wide tape

REMOVING THE INJECTORS:

1. Open the driver's door and pop open the door that covers the fuse panel, as shownbelow.

2. Remove the fuse for the fuel pump (#28), indicated by the red arrow in the picturebelow.


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3. Start the engine and let it stall out. This will remove the pressure from inside the fuellines so that you won't get sprayed in the face with gas later on.

4. Loosen the gas cap to vent any residual pressure. This step may not be necessary,but it can't hurt.

5. Remove the engine covers and upper intake manifold from the top of the engine byfollowing the appropriate steps in this DIY by FaelinGL (Mike).

6. The injectors are located on top of the lower intake manifold, as indicated by the redarrows in the picture below.

7. Before proceeding, cover the holes in the lower intake manifold with some tape (redarrow) if you haven't already.


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8. The wires for the fuel injectors (as well as the rear knock sensor) are contained in asupport (yellow arrow in picture below) that is attached to the fuel rail (green arrow) inthree places (blue arrows). Before removing the support, there are 6 retaining clips(red arrows) that first need to be popped open in order to remove the wiring.

9. The picture below shows the clip that secures the wiring for the #3 and #4 cylinderinjectors. To pop open this and the other five clips, use a small screwdriver placed inthe slots indicated by red arrows to gently pry them open. The yellow arrows in thepicture show how the support is attached to the fuel rail (it's simply clipped on to bothtubes).


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10. The picture below shows how the individual wires for injector #1 (rred arrow) andinjector #2 (yellow arrow) are secured below their retaining clip.

11. Once all of the retaining clips are open, carefully remove the wiring from thesupport, unclip the support from the fuel rail and manuever the support out fromaround the wiring. The picture below shows the support removed.


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12. The following three pictures show how the injectors are oriented in the lowermanifold. Their orientation is important since the upper manifold sits just above theinjector harnesses and you want to avoid any interference. The injectors for oddnumbered cylinders are oriented so that the electrical harness is roughly straight up,while the injectors for the even numbered cylinders are rotated approximately 45°counter-clockwise (towards the passenger's side). The injector for cylinder #1 isrotated slightly clockwise (towards the drvier's side) so that there is no interferencewith the wiring support when installed.


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13. Remove the electrical harneses from all six injectors by pressing in on the tworetaining clips (red arrows in picture below) and then pulling up on the harness (yellowarrow).


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14. Work the wiring and harnesses for the six injectors out from underneath the fuelrail.

15. Disconnect the wiring for the rear knock sensor from the top of the valve cover. Thetwo retaining clips, indicated by the red arrows in the picture below, should easily liftup out of their holes in the valve cover. You shouldn't need to undo the wiring from thewiring clips, but can if the clips so not easily come out of the cover.

16. Pull the vacuum line T-fitting off of the fuel pressure regulator on the fuel rail, asshown below.


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17. Move the injector and knock sensor wiring out of the way (red arrow in picturebelow).

18. Unclip the flexible fuel lines from their retaining clips (red arrows in picture below)by placing a small screwdriver in the groove at the top of each clip (yellow arrow) andcarefully prying it open. The left clip in the photo has already been opened.


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19. Unclamp and remove the fuel lines from the fuel rail, as shown in the picture below.Use a rag or paper towel to catch the small amount of gas that will come out. Also,note the position of the clamps on the hoses before removing the clamps. The clampsshould be put back in the same position so that the tabs won't sit underneath the uppermanifold when it's reinstalled. This is just a guess, but you probably don't want to haveto take the manifold back off to work on the fuel lines if need be at a later date.

20. If the car is going to sit for a while for whatever reason, then I recommend that youplug the fuel lines, as shown in the picture below. Mine sat for a week and a half while Iwas on vacation and the injectors were shipped out for cleaning and I didn't want thegarage filling up with gas fumes. If you're reinstalling injectors immediately afterremoving them, then this step is not necessary.


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21. Pop off the clips that secure the injectors to the fuel rail (red arrows in picturebelow) by pulling straight up on them. They're "springy" and should pop off easily.

22. The picture below shows one of the clips partially removed. Note the slots in theside of the clip where the flange on the fuel rail fitting sits.


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23. The picture below shows one of the retaining clips completely removed.

24. The picture below shows the proper depth of the injector in the fuel rail fitting. Theretaining clip slides into the groove in the injector (red arrow) and around the flange onthe fuel rail fitting. Note that when the injector is sitting in the fuel rail fitting at theproper depth, the distance between the flange and groove is appoximately equal to thewidth of the groove.


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25. The fuel rail is secured to the lower manifold by four 5mm hex bolts in locationsindicated by the red arrows in the picture below.

26. The picture below shows a close-up of one of the fuel rail bolts. Remove all four ofthese bolts.


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27. Carefully pull the fuel rail off of the injectors by pulling a little at a time at variouspoints along the length of the rail, as shown in the picture below. The o-rings securethe injectors into the rail pretty good, so you may need to give it a good tug. Just don'tpull so hard as not to bend the fuel rail. It doesn't matter if the injectors stay in themanifold or come out with the fuel rail. All of my injectors stayed in the manifold, butsome were loose and close to coming out with the rail.

28. Carefully wiggle/rotate the injectors out of the manifold. You can use the harnesson the injector for a little bit of leverage, but don't put too much pressure on it or itcould possibly break off. The injectors should come out eventually with gentlewigging/rotation so don't get impatient if it seems like they're completely stuck. Mostlikely they're not.


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29. Check the fuel rail fittings for any o-rings that might have popped off the injectorsand remained in the fittings.

30. Also check the holes in the lower manifold for any o-rings that might be present.Note: If you look into the injector holes in the lower manifold for the front (even)cylinders, you should be able to see the intake valve for each cylinder (green arrow).Mine showed very little deposit on the valve even after 216k miles!


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31. If the car is going to sit for a while, cover the injector holes in the lower manifoldwith tape so that nothing falls in.

REINSTALLING THE INJECTORS:

The reinstallation of the injectors is done by simply following the above steps inreverse. Here are some simple tips which should help make the process easier:

- Apply some gas or a small bit of clean oil to the injector o-rings before pushing theinjector into the manifold or fuel rail. They'll go in much easier this way.

- Figuring out how far the injectors should be pressed into the manifold and fuel rail canbe a trial-and-error process. I recommend fitting the injectors into the manifold firstand then pressing the fuel rail on. Use the picture in Step #24 to gauge if the injector ispositioned properly. If it isn't, move the injector in the appropriate direction so that theflange and groove look like they do in the picture. When the groove and flange are


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related this way, then the injector clips will slide on very easily. Since the fuel rail isbolted a specific distance away from the manifold, you only need to correctly positionthe fuel rail end of the injector. The manifold end of the injector will be positioned inthe manifold accordingly.

- Torque the fuel rail bolts to 7 ft-lbs if you have a torque wrench.

- Don't forget to reinstall Fuse #28 or the car won't start.

Congrats on a job well done. Have a or two.

As always, do this procedure at your own risk. I am not responsible for anymistakes in the above procedure or those that you make while performing it.

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Re: DIY - Replacing fuel injectors on a MKIV12v VR6 (VgRt6)

What can I say !! Gary strikes again Next time do a headgasket procedure

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Sep 14th, 19994,305

fastslc

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12-12-2006 08:25 PM #2

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Re: DIY - Replacing fuel injectors on a MKIV12v VR6 (fastslc)

What a great writeup!

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Dec 18th, 2005836

otisranson

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12-12-2006 11:23 PM #3

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Re: DIY - Replacing fuel injectors on a MKIV12v VR6 (otisranson)

you do an awesome job on these tutorial things!

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Feb 18th, 2004946

procket2_8

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12-13-2006 12:16 AM #4

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Thanks.

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VgRt6

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12-13-2006 12:42 AM #5


17 of 22 1/12/2012 2:31 AM

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nice write up.

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Oct 4th, 2005HV, NY4,271Bagged Fif

VDFOSHO

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12-13-2006 01:06 AM #6

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the man!Join Date:Posts:

Aug 20th, 2006846

Mr. Chris

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12-13-2006 01:08 AM #7

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Morning bump.

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Mar 8th, 200216,088

VgRt6

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12-13-2006 11:06 AM #8

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Great writeup Gary


Mar 31st, 2002San Diego7,6902011 S4

RavinJetta

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12-13-2006 01:31 PM #9

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Re: (RavinJetta)


Nov 27th, 2004Charlotte, NC6,9092000 VW Jetta VRT,

FaelinGL

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12-13-2006 01:58 PM #10


18 of 22 1/12/2012 2:31 AM

EXCELLENT DIY. I know I need to do this badly, with my aging 12V.Mike

2000 Audi TT Quattro

Chapter 11 Dubs: Member #001http://www.chapter11dubs.com-----------------------

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Re: (FaelinGL)

Nice diy I was going to do this to my buddies VR this week. Thanks

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Jan 31st, 20045,263

njwolfturbo

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12-13-2006 02:11 PM #11

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Thank you for sharing. once again, Herr Docktor Gary!!Join Date:Location:Posts:Vehicles:

Feb 13th, 2003Thornton, CO2172K VR6 Jetta

VR6_00Jetta

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12-15-2006 02:59 AM #12

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Re: DIY - Replacing fuel injectors on a MKIV12v VR6 (VR6_00Jetta)

If only VF Engineering would hire you to write their manuals...I had to do this blind.Nice Work...AGAIN! you have saved me countless hours when working on my car

Modified by darkVR6 at 11:27 PM 12-14-2006Join Date:Posts:

Feb 11th, 2005651

darkVR6

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12-15-2006 03:18 AM #13

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Re: DIY - Replacing fuel injectors on a MKIV12v VR6 (darkVR6)

Quote, originally posted by darkVR6 »

If only VF Engineering would hire you to write their manuals...I had to dothis blind.Nice Work...AGAIN! you have saved me countless hours when working onmy car

Modified by darkVR6 at 11:27 PM 12-14-2006

Tell them to send me parts. I'll install them and write their manuals.

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VgRt6

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12-15-2006 08:28 AM #14


19 of 22 1/12/2012 2:31 AM

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great write up! thanks again! keep going man! waiting for more of your DIY!Join Date:Posts:

Jul 10th, 200435

bensonwu

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04-12-2007 11:29 PM #15

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Re: DIY - Replacing fuel injectors on a MKIV12v VR6 (bensonwu)

Another boring, uninformative, vague and hard to follow DIY post without enoughphotos from VgRt6


Jun 9th, 2000OREGON7,41693 SLC, 07 Legacy GT,

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kevwithoutacorrado

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04-13-2007 06:53 PM #16

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Re: DIY - Replacing fuel injectors on a MKIV12v VR6 (kevwithoutacorrado)

vague and informative????really.....this is one of the coolest diy's yet.

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May 9th, 2007Sarnia, Ontario,

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CorvetteKillerVr6

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05-27-2008 12:01 PM #17

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my car gets pretty bad gas mileage (200 city miles a tank) and my friend gets like260ish..we drive the same..his car has better throttle response and im running a littlerich..could this be my injectors? and also i probably need my tb cleaned..anysuggestions?

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Mar 5th, 2008974

jdubb531

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11-28-2008 01:45 AM #18

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Re: DIY - Replacing fuel injectors on a MKIV12v VR6 (CorvetteKillerVr6)

Quote, originally posted by CorvetteKillerVr6 »

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kevwithoutacorrado

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08-09-2009 01:49 AM #19


20 of 22 1/12/2012 2:31 AM

vague and informative????really.....this is one of the coolest diy's yet.

hahaha

I was searching for injector information today and found this post. can't believesomeone thought I was serious! the was for real - ha

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Thank YOU!I now feel comfortable doing this job myself,wouldnt have otherwise.Cant thank youenough!

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Jan 12th, 2002108

cchetlan

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05-01-2010 03:45 PM #20

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EPC light came on

Hey thanks for the guide. I followed it completely and replaced one of the injectors onmy brother's 2001 VR6 and the car started up fine when I was done, but now the EPClight is on. I was wondering if I should reset the computer and drive it around a bit or ifthere is actually something that needs to be fixed. Thanks

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Apr 2nd, 20111

scruffler

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04-21-2011 05:03 PM #21

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thinking I am going to need to do this to see if it fixes my 6 cylinder misfire. I havetried everything else I hope this does the trick... Anyone know where I can get a vr6injector for a decent price? Seem some for like 185 but damn LOL...

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Feb 18th, 20023,936

gqjeff Member

05-17-2011 11:47 AM #22

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hey i just did mine and im laking gas,probly the old o ring on the old ones right? but imgetting new ones is there a way to test them to see if they are leaking with out puttingthe manifold back on and starting the engine??

thank you!mikeJoin Date:

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Nov 5th, 2008long island1602001 gti glx vr6, 1989

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odawg753

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08-24-2011 10:56 PM #23

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my vr6 borla exhaust http://www.youtube.com/watch?v=Vq3i3D-sdLE

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vwvortex.com - diy - replacing fuel injectors on a mkiv 12v vr6

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