air in the fuel system?

CarpeDiesel

Member
Joined
Jan 24, 2016
Location
colorado
TDI
2004 jetta
Hello. I have an 04 mkIV tdi.

I replaced the fuel filter, but I didn't fill the new canister with fuel afterwards. Of course, the car died about 30 seconds after I started it. After learning what I did wrong I filled it up to the top of the filter, but it still doesn't start.

Two questions: How much damage have I done, and how do I get the air out of there and get it going again?

One caviat: I don't have VCDS or a laptop, so a vag-com free solution would be preferred.

Thank you.
 

jettawreck

Top Post Dawg
Joined
Aug 2, 2004
Location
Northern Minnesota-55744
TDI
2001 Jetta and 2003 Jetta
No damage, but it will take several intervals of cranking.
If you have MitiVac or something similar you can pull some fuel thru the filter, and pump from the return line.
Loosen a couple injector lines from the injector bodies to purge the air and after it starts to pump generous squirts of fuel reattach them and hopefully it will soon start up.
Don't crank too long of intervals and overheat the starter.

Edit: Missed the '04 part. Since its a PD the electric lift pump should fill the system with a few on/off cycles of the key. It should soon start on its own unles the lift pump has previously died (in some cases some cars seem to run w/o it until they someday just don't, especially if they are run out of fuel). Verify the lift pump works/buzzes/hums when you cycle the key ON. It will help to lift up the rear seat cushion and/or have someone cycle the key for you. Without starting the prime cycle should only be. Couple seconds of running.
 
Last edited:

DCannon

Well-known member
Joined
Aug 17, 2016
Location
Madison, Alabama
TDI
Black 02 Jetta automatic, tan leather, new Sachs front struts/Bilstein TC rear shocks
Something to try: I know this is going to sound crazy, but go around to the back of the car and kick the gas tank. Not a 'goal kick', just a forceful tap. The same thing happened to me after replacing the fuel filter on my '02 TDI. I forgot to fill the new filter with fuel, engine wouldn't start, so called the local VW/Audi specialty shop and the mechanic I spoke to suggested kicking the gas tank to help remove any air bubbles that may have formed at the pump during the replacement/starting process, as apparently can sometimes happen. I did, and it started with no problem. I thought the guy was messing with me, but it worked.
 

PGM jetta

Veteran Member
Joined
Dec 14, 2015
Location
Northern Alabama
TDI
05 Jetta BEW
It will be hard to crack any injector lines loose if it's a PD...

Make sure your in-tank lift pump is working properly, then just crank it several times and it will start. If you have a mityvac or similar then you can pull fuel from the return line to prime it

DCannon: unless you or a previous owner installed a lift pump in your 02 then you don't have a "pump" in your tank
 

DCannon

Well-known member
Joined
Aug 17, 2016
Location
Madison, Alabama
TDI
Black 02 Jetta automatic, tan leather, new Sachs front struts/Bilstein TC rear shocks
PGM jetta: I certainly haven't installed anything, nor has anyone else (I'm the original owner), so just to check the mechanic's suggestion against what you're telling me and satisfy my own curiosity, I Googled "Fuel pump 02 jetta tdi" and saw a couple YouTube videos showing the pump/sending unit access located under the rear seat. Having never had any need to check my car for this, I just checked and sure enough, there it was...same as in the videos and what was being referred to as the fuel pump/sending unit... so took some photos. Is this not the pump/sending unit?




 

jettawreck

Top Post Dawg
Joined
Aug 2, 2004
Location
Northern Minnesota-55744
TDI
2001 Jetta and 2003 Jetta
That's just the fuel pickup and gauge sending unit. Not an electric fuel lift pump. See, only two wires for the gauge. Lift pump has four (or five?) wires. No OEM lift pump in a 2002 TDI.
Don't believe everything you google or YouTube.
 

DCannon

Well-known member
Joined
Aug 17, 2016
Location
Madison, Alabama
TDI
Black 02 Jetta automatic, tan leather, new Sachs front struts/Bilstein TC rear shocks
PGM jetta and jettawreck: I stand corrected and thanks so much for the info and lesson in what's what and correct component identification.
 

CarpeDiesel

Member
Joined
Jan 24, 2016
Location
colorado
TDI
2004 jetta
I picked up a Mityvac and pumped fuel out of the return line until it started coming out with no air bubbles.

After that, it started up on the second crank.

My check engine light is on now, but otherwise it seems to run better than ever.
 

CarpeDiesel

Member
Joined
Jan 24, 2016
Location
colorado
TDI
2004 jetta
By the way, I don't hear the lift pump engaging when I turn the key ON, and the helper who listened at the tank for me didn't either, so that's good info and another project for me.

Thanks for all the help.
 
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