01 jetta won't start

golstho

Well-known member
Joined
Aug 13, 2008
Location
al
TDI
06 jetta
01 jetta tdi will not start if the car is parked for more than about two days. it will just turn over and over. noticed that the clear line on top of the fuel filter is not filled with fuel but instead air. so i guess this is the problem but how would the fuel system be getting air in and loosing prime. i can start the car with starting fluid and it will eventually start and then run fine, but if you don't crank it like every day it won't start. please help!
 

Powder Hound

Top Post Dawg
Joined
Oct 25, 1999
Location
Under a Bridge, Crestview, FL, USA
TDI
'00 Golf 4dr White 5sp, '02 Jettachero 5sp, Wife's '03 NB Platinum Gray auto(!)
You need to check all the connections around the fuel filter. The plastic thermo 'T' can crack and let air in. Also, the 2 o-rings on the insert into the filter can leak. There's also the connections of the fuel line to the injection pump, and the fuel return tubing. All this stuff can leak air into the system, so it does not appear to be problematic because fuel is not leaking out.

There is also supposed to be a check valve in the fuel sending unit inside your tank that prevents leakback into the tank from that fuel line. If the line becomes filled with air instead of fuel, you'll experience the problems you are having. It is not a quick easy task you have to chase down the leak, but it is basically the only way to find and fix your problem.
 

steelmb

Veteran Member
Joined
Apr 12, 2009
Location
MB
TDI
2003 Jetta Wagon
golstho said:
01 jetta tdi will not start if the car is parked for more than about two days. it will just turn over and over. noticed that the clear line on top of the fuel filter is not filled with fuel but instead air. so i guess this is the problem but how would the fuel system be getting air in and loosing prime.:eek: i can start the car with starting fluid :eek:and it will eventually start and then run fine, but if you don't crank it like every day it won't start. please help!
:mad: Very bad. Do a search.
 

golstho

Well-known member
Joined
Aug 13, 2008
Location
al
TDI
06 jetta
thanks power hound! still have not fixed or found the problem yet.
 

golstho

Well-known member
Joined
Aug 13, 2008
Location
al
TDI
06 jetta
i replaced the two o rings on the thermo t. checked all the hoses aroung the filter they are old and showing signs of surface cracking but i dont think they are the problem. filled the filter up with fuel the car primed cranked and ran fine......let it sit over night and it wont start....while trying to start the car the clear part of the fuel line begins to fill with fuel but when you quit turning the engine over the fuel leaks back out of the line to the filter....any suggestions????? could this have anything to do with the in tank pump???
 

runonbeer

Maintenance EnthusiastVendor
Joined
Apr 15, 2002
Location
Austin, TX/Chapel Hill, NC
TDI
'00 Golf 02M, '10 Golf 02E, '02 UTE 02M
No pump in the tank.

Look for fuel puddles/wetness under/on/around the injection pump.

Replace the "tee" on the filter for good measure (part # 1J0127247A )

go to harbor freight and get a "mity-vac" to prime the pump.

cranking on a dry pump is no bueno.
 

Powder Hound

Top Post Dawg
Joined
Oct 25, 1999
Location
Under a Bridge, Crestview, FL, USA
TDI
'00 Golf 4dr White 5sp, '02 Jettachero 5sp, Wife's '03 NB Platinum Gray auto(!)
golstho said:
i replaced the two o rings on the thermo t.
Those can leak brand new if the thermo t doesn't have a snug fit into the filter. Just for grins, try a generous coating of vaseline on that lower portion of the t when you insert it.
golstho said:
...while trying to start the car the clear part of the fuel line begins to fill with fuel but when you quit turning the engine over the fuel leaks back out of the line to the filter....
So the clear line is the one running from the filter to the pump. Does the fuel seem to just back off into the filter or are there any bubbles that are coming from somewhere perhaps indicating which direction the fuel is moving? On first blush it sounds to me like the check valve (IIRC it is in the fuel sender in the tank) isn't holding.
 

golstho

Well-known member
Joined
Aug 13, 2008
Location
al
TDI
06 jetta
going to order a new fuel T and o rings and for extra measure i may replace the fuel lines too.
the clear line is on the supply line from the pump to the filter and the fuel is draining back to the filter and it does have air bubbles in the line as well, but it never really fills all the way up with fuel.
the only way i can get the car to start is to take the T off the filter and fill it with fuel and the car will start.
also if i buy a mighty vac how will i prime the ip? is there a how to on this?
 
Last edited:

runonbeer

Maintenance EnthusiastVendor
Joined
Apr 15, 2002
Location
Austin, TX/Chapel Hill, NC
TDI
'00 Golf 02M, '10 Golf 02E, '02 UTE 02M
Hook the mity vac to the small cloth line that goes to the #4 injector (leaving the line hooked to the pump). Leave all other fuel lines in place. Pump on the pump until you get fuel and no bubbles in the line of the tool.

Then you must loosen some hard injector lines while cranking the engine to purge the air out.
 

golstho

Well-known member
Joined
Aug 13, 2008
Location
al
TDI
06 jetta
thanks runonbeer! will have to get one of those.
the intank valve theat keeps the fuel from leaking back to the tank....is this a part of the sending unit? cus the local dealership's parts department told me the only thing his computer showed in the tank was a fuel sending unit.
 

golstho

Well-known member
Joined
Aug 13, 2008
Location
al
TDI
06 jetta
update. pulled the lines to the fuel sending unit under the seat off. both dripped fuel. i figured that if there is a valve in the unit on the return side to keep fuel from flowing back to the tank then i would not be able to blow in it either.....wrong....both the return side and the feed side i was able to blow through. so is this bad? does this mean i will have to buy a sending unit cus they are expensive from the dealership.

also was able to crank the car and bleed all the air out of the lines at the injectors. would be nice if that fixed the problem but i doubt it....not with my luck!
 

Jimmyzw22

New member
Joined
Feb 19, 2010
Location
California
TDI
Jetta 03 and Beetle 01
Check your engine speed sensor. Hook up vag com check engine module 003 and look at the rpm while cranking. I have had the same problem and was looking at air in pump but it was the engine speed sensor connection. just an idea
 
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