2003 Golf TDI Fuel Problems

1973MG

Member
Joined
Mar 18, 2018
Location
Connecticut
TDI
2003 Golf
Hey everyone!
I just got done driving from Connecticut to Maine, no problems on the whole 7 hour drive. Started the car the night I arrived to go pick up a pizza, no issues then either. The next morning I went to start it and it cranked and cranked and cranked until it died. The car has 198,000 miles on it.

I browsed these forums a bunch and watch a ton of YouTube tutorials and realized that I've been experiencing symptoms of fuel restriction for a while; long crank times, spluttery starts, etc. This time when it died the fuel line between the filter and injection pump was completely dry. I replaced the fuel sending unit and attached a vacuum pump to the main line between the fuel filter and the injection pump to try and bleed the air from the system. I managed to suck tons of bubbly fuel out of the filter, but I clearly wasn't getting any fuel from the tank.

I hooked up the pump to the send line on the sending unit and built up vacuum, but couldn't seem to suck fuel out of the tank at all. Is it possible that the little brake bleeder hand pump I have isn't building enough vacuum to open the check valve on the sending unit?

Sorry for the long post, I'm just super stumped on this and felt like I was doing everything right only to hit a really big speedbump after doing all this work.

EDIT: I just went out and tested my shutoff valve. It seems to be working fine, so I don't think it was a misdiagnosed relay 109 issue.
 
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IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
How old is the fuel filter? Even if it's fairly new, I'd suspect bad fuel and replace it.
 

1973MG

Member
Joined
Mar 18, 2018
Location
Connecticut
TDI
2003 Golf
Thanks for the response!

I don't know if the fuel filter has ever been replaced. I'll swap that out next. I'm still wondering why I can't suck fuel directly from the tank through the new sending unit. I've seen other threads talk about how little vacuum it should take to pull fuel from the pickup, and I'm just not having any luck.
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
Pretty cold today. 20s last night, didn't get out of the low 30s today. And we've had a lot of problems with pump fuel gelling this winter.
 

whitedog

Veteran Member
Joined
Jul 12, 2004
Location
Bend, Oregon
TDI
2004 Jetta that I fill by myself
Pretty cold today. 20s last night, didn't get out of the low 30s today. And we've had a lot of problems with pump fuel gelling this winter.
So not cold enough for gelling.

Are you positive you have the correct sending unit?

If so, pull it out and see what's going on. Is it possible something like a plastic bag is in the tank? Your pump should be able to pull fuel from the tank, through the filter and IP.
 

1973MG

Member
Joined
Mar 18, 2018
Location
Connecticut
TDI
2003 Golf
I grabbed the part number from a YouTube tutorial on replacing the sending unit. It looks identical to the old one.

In terms of gelling, it has gotten in the low teens and stayed there for days, but I don't recall how cold it was the night that it decided to stop working. When I was digging around in there the fuel looked fine. I pulled the new sending unit out of the tank after replacement to see if it looked clogged and to see if I could pull air through it without it actually in the tank (I couldn't) and there was liquid fuel sitting in the pump body. Could I have a clogged return line?
 
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whitedog

Veteran Member
Joined
Jul 12, 2004
Location
Bend, Oregon
TDI
2004 Jetta that I fill by myself
When I was digging around in there the fuel looked fine. I pulled the new sending unit out of the tank to see if it looked clogged and to see if I could pull air through it without it actually in the tank (I couldn't) and there was liquid fuel sitting in the pump body. Could I have a clogged return line?
Were you trying to pull fuel from the return line?
 

1973MG

Member
Joined
Mar 18, 2018
Location
Connecticut
TDI
2003 Golf
Were you trying to pull fuel from the return line?
I was trying to pull fuel through the pump with the return line attached. Now that I think about it the physics of the suction that I was imagining in my head don't really make sense, haha.
 

wonneber

Top Post Dawg
Joined
Oct 12, 2011
Location
Monroe, NY, USA
TDI
2014 Jetta Sportwagon,2003 Jetta 261K Sold but not forgotten
Do you see a small bubble in the clear fuel line going to the pump?
Did you check the ASV is open? Disconnect the vacuum hose going to it, make sure it's open and try starting.
I'm not ruling out jelling which it does sound like.
I would have thought there should have been enough fuel in the pump to start it and run for a minute.
 
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