Cold Start Problems

fpruter

Active member
Joined
Aug 6, 2007
Location
Virginia Beach, VA
TDI
2000 VW Jetta GL TDI
I have a 2000 VW Jetta TDI and it has problems starting in the mornings or after a long period of the engine not running. I have checked the glow plugs as well as the battery. The car will try to start and generally takes 30-60 seconds.

I've read somewhere online that if there is an air bubble in the fuel line it would cause that to happen. When looked under the hood I see a massive air bubble... a good inch to inch an a half long. Today, my friend noted that when the car finally started up the bubble was pushed through first.

Any suggestions on how to fix this problem or other possible solutions?

Thank you,
Francis
 
Last edited:

david_594

Top Post Dawg
Joined
Feb 28, 2004
Location
Cheshire, CT
TDI
2000 Jetta GLS Silver
A 1" air bubble isnt too out of line although your problem does sound like air is getting into your fuel system.

Take a look at your fuel pump and see if you can see any signs of leakage on the pump?
 

mikica

Veteran Member
Joined
Jun 22, 2007
Location
Belgrade
TDI
golf v
That sounds to me like deposits on intake valves.You should have compresion checked.The glow plugs are only turned on only at temperatures below 5 degrees.Also it would not be bad to check injection timing.
 

Canadian_Grizzly

Veteran Member
Joined
Apr 7, 2005
Location
British Columbia, Canada
TDI
02 Jetta TDI
Check the fuel lines between your injectors and the return line. They are probably due to be replaced. If there is a leak fuel will siphon back into the tank. Could also be the fuel sending unit in your tank. I believe yours will have a check valve that is suppose to stop this from happening as well. Air intrusion can also happen with incorrectly installed orings on the T fitting on top of the fuel filter. If this problem surfaced soon after a filter replacement start there and just for giggles reach under the canister and ensure that the drain is tight.
 

fpruter

Active member
Joined
Aug 6, 2007
Location
Virginia Beach, VA
TDI
2000 VW Jetta GL TDI
david_594 said:
A 1" air bubble isnt too out of line although your problem does sound like air is getting into your fuel system.

Take a look at your fuel pump and see if you can see any signs of leakage on the pump?
From what I can tell I don't see any signs of leakage on the pump. Any other suggestions?
 

fpruter

Active member
Joined
Aug 6, 2007
Location
Virginia Beach, VA
TDI
2000 VW Jetta GL TDI
Canadian_Grizzly said:
Check the fuel lines between your injectors and the return line. They are probably due to be replaced. If there is a leak fuel will siphon back into the tank. Could also be the fuel sending unit in your tank. I believe yours will have a check valve that is suppose to stop this from happening as well. Air intrusion can also happen with incorrectly installed orings on the T fitting on top of the fuel filter. If this problem surfaced soon after a filter replacement start there and just for giggles reach under the canister and ensure that the drain is tight.
I actually purchased this car with a starting problem. I figure I would be able to fix it if I put the time and effort into it. I have recently changed the fuel filter and the same problem occurs. I see no fuel leaks nor when I stick my hand under the cansiter do I feel any liquids and it will no tighten any further.


Thanks for the input in any case.
Any other suggestions?
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
If the return lines are old, change them. This problem is not fuel leaking out, but air leaking in, which makes it somewhat more difficult. If there is a slight hole, it allows air in, and the fuel goes to the tank (slightly downhill there - so slight suction). There is generally no signs of a real fuel leak unless it's under the cannister, which you've checked.

If this has been chronic, and the fuel return lines look almost new, I'd very carefully look over the "t" - perhaps even replace it. A slight nick in it where the orings go, or slight crack in it, can cause this type of problem.
 

fpruter

Active member
Joined
Aug 6, 2007
Location
Virginia Beach, VA
TDI
2000 VW Jetta GL TDI
mikica said:
That sounds to me like deposits on intake valves.You should have compresion checked.The glow plugs are only turned on only at temperatures below 5 degrees.Also it would not be bad to check injection timing.
How do I do a compression check as well as check the injection timing?
 

fpruter

Active member
Joined
Aug 6, 2007
Location
Virginia Beach, VA
TDI
2000 VW Jetta GL TDI
rdkern said:
If the return lines are old, change them. This problem is not fuel leaking out, but air leaking in, which makes it somewhat more difficult. If there is a slight hole, it allows air in, and the fuel goes to the tank (slightly downhill there - so slight suction). There is generally no signs of a real fuel leak unless it's under the cannister, which you've checked.

If this has been chronic, and the fuel return lines look almost new, I'd very carefully look over the "t" - perhaps even replace it. A slight nick in it where the orings go, or slight crack in it, can cause this type of problem.

Are you talking about the fuel lines under the car? Are there lines under the hood that should be replaced as well?
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
No - the lines that take the excess fuel from the injectors back to the filter.
 

Birdman

Top Post Dawg
Joined
Apr 7, 1999
Location
Near Hagerstown MD.
TDI
Jetta 2001 Died by Truck one snowy day. Jetta 2003
Most likely the problem is the pump timing is off. Use the Vag-com list above the forums for someone in your area and ask them to help you. IF you were a bit closer I would do it. But 8 time out of 10 that will be the problem. Bubbles are normal in the fuel line and unless the T valve O-rings on the Fuel filter are letting air in that is not your problem.
 

fpruter

Active member
Joined
Aug 6, 2007
Location
Virginia Beach, VA
TDI
2000 VW Jetta GL TDI
I did some more looking and I found that although the bubble may start about an inch, if I crank the engine for a good 10 seconds and stop it before it starts, it will grow to about the size of the clear fuel line. However, once it goes away the engine will start. When I left it running for a few minutes, I can turn it back off most of the bubbles are gone and it will start with very little (only about a second or 2) complaining. If I turn it off immediately after it start and try to start it again it will struggle.


The fuel lines as far as I can tell have no crack in them. How would I test to see if I needed to get a new connection piece?

Also, I found someone in the area who will be able to run his Vag-Com on my car next week.

Thanks.
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
I'd be tempted to "throw" a new "t" connector on it. Look at the one you have with a magnifying glass - see if there are any cracks to be seen.
 

fpruter

Active member
Joined
Aug 6, 2007
Location
Virginia Beach, VA
TDI
2000 VW Jetta GL TDI
Hmm... I left my car off for a couple of hours and the fuel line has small bubbles however it still has problems starting... I just thought I'd give an update.

Another thing to add is that when it finally does start it pours a lot of smoke out of the exhaust.
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
fpruter said:
Another thing to add is that when it finally does start it pours a lot of smoke out of the exhaust.
Do you know anyone with a VagCom? I'd be curious as to what temperature the ecu is reading (I'd guess the fuel temp would be most important).

Timing could be a problem too. VagCom would be helpful.
 

fpruter

Active member
Joined
Aug 6, 2007
Location
Virginia Beach, VA
TDI
2000 VW Jetta GL TDI
I have contacted someone who lives near by off the list and will be doing it next week.

Do I run the tests on the already warmed up car or while it's struggling to start?
 
Last edited:

zaeli

Veteran Member
Joined
Dec 3, 2005
Location
North Carolina
TDI
99.5 golf 175k (totaled, sold) 2000 golf tdi 375k (Malone 1.5) 2002 green diesel bug
Seems to plague tdi's with 150,000 miles or so. Mine has 143k (99.5 golf) and has slow start issues, worse in the winter. The only code it throws is 16764. That fault code should not be affected durring warmer months.
 

Mad_Dasher

Veteran Member
Joined
Jan 10, 2005
Location
Indianapolis
TDI
2002 silver Jetta
Am I missing something here? The anti-shudder valve is a common problem for cars not starting when cold.
 

fpruter

Active member
Joined
Aug 6, 2007
Location
Virginia Beach, VA
TDI
2000 VW Jetta GL TDI
The anti-shudder valve from what I can tell has no problem.. I can push it easily in and it comes right back out when I let go.
 

fpruter

Active member
Joined
Aug 6, 2007
Location
Virginia Beach, VA
TDI
2000 VW Jetta GL TDI
After looking closer, I realized when my car is running, a lot of air bubbles are flowing through the fuel line. I am going to try to replace all the fuel hoses.
 

fpruter

Active member
Joined
Aug 6, 2007
Location
Virginia Beach, VA
TDI
2000 VW Jetta GL TDI
I went to the VW dealership and was informed it would cost $400 to replace the fuel lines just under the hood. I instead ordered a new tee connector and will try that first.
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
fpruter said:
The Vag-Com diagnostic came up with nothing... Any other suggestions?
So, what fuel temp did it read? If you can test this temp when the engine is totally cold, it give you a good idea if it's calebrated properly at that temp (ie, room temp). Keep track if it when the fuel gets warm - many report the temp being 180C-ish when warm.

Re the "T" connector - make sure to have new O-rings with it. If you couldn't see any cracks in the T, it may be as simple as the o-rings.

Good luck with this.
 

fpruter

Active member
Joined
Aug 6, 2007
Location
Virginia Beach, VA
TDI
2000 VW Jetta GL TDI
Any suggestion on how I can locate where I'm getting air? Replacing all the fuel lines under the hood will cost $400 if I buy the parts from VW.
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
Have you changed the fuel filter? I don't remember if this has been done. If not, it might be time.
 
Top