04' Jetta Cold = start / Warm = Cranks no start

I recently bought an 04 TDI Jetta from my brother. He has had it for about 3 years with no issues. I have had it for 3 weeks no issues.

Two days ago I left work drove about 15 miles or so, plenty of time to get her warmed up to full temp, and pumped her full of fuel. (vented completely full in the filler neck NOTE: this is the first time I have ever filled it this full)

Got in it started it up no problems and drove about 2 miles to the autoparts store, shut it off and went in.

Came out and it would not start, it will crank like no bodys business, but will not even attempt to fire. The Glow Plug light does come on every time.

So I called some people, messed with some stuff. Maybe 30min-1hr. later I got in it and it started with the bump of a key.... Jumped in and drove her to the house about 5 miles. Shut it off at the house, tried again, and nothing just turns over won't start. Let it sit about an hour, starts right up.

Next morning, Cranks right up, never started easier. Drive to work, 15 miles, shut it off. Tried to crank it back up and will not start just turns over.

So the things I can narrow down.

1) I did pull the battery from the key FOB the day all this stuff began, and it doesn't work anymore....
2) First time to my knowledge this thing has ever been filled COMPLETELY full of fuel, which shouldnt do anything.
3) The Glow Plug light does come on every time.
4) Car starts fine cool
5) Will not start warm, only turn over (with plenty of speed rpms)
7) No Check Engine Light
6) Started two days ago, and has never done this before.

Any Ideas?

109 relay?

Yea I have read about that some, but why would it be fine cold, and not when warm?

Well according to a VIN break bown it is actually an 05', just the old body style. If that makes any differance.

The PDs don't have the 109 relay problem. It is not related to the remote key battery either.

I would concentrate on the engine speed sensor. When it won't start hot, see if a cranking RPM is recorded when using a VCDS scan tool.

I would also verify the intank fuel lift pump works when the no-start ocurrs. After a no-start, listen for the pump to run for 1-2 seconds when the key is turned "on" (don't engage the starter). The pump is in the fuel tank, under the right rear seat bottom. Lift up the seat bottom so you can hear the pump better, if it is working.

--Nate

Nate,

Does the lift pump sound similar to fuel pump on a normal gas vehicle? My older brother had me listen for this when I called him the very first time this happened, and I heard absolutely nothing (With the back seat up and carpet flap pulled back.)

If this is the problem, why would the car start perfectly fine when cold and not when hot?

It has been sitting since I got to work this morning, I think I'll walk down and listen to it now and report back.

Thanks for the responses so far,

Evan

Went out to the car with a co-worker, just for back up ears. I had them listen directly at the cover plate under the rear passenger seat while i turned the key. No sound at all.

We switched places, and I heard nothing at all.

It still starts cold... and apparently the pump isnt working. How can this even happen?

Thanks,
Evan

Evan:

With the seat up you will hear it if its working. Just for a second, though. No sound = most likely a failed lift pump. You can double check by removing the "fuel in" line to the fuel filter, placing the line's end in a bottle and turning on the key. You should get a nice burst of fuel through the line. If not, 90% chance the pump failed and not the power to the pump. You can then verify it is not an electrical issue by mesuring voltage at the pump plug (remove the cover plate under the seat for access). The two larger wires are the power wires (smaller ones are for the fuel guage). Brown is always the ground. Remember, as the key is turned on, the wirres will power up for only a second or so (power stays on if the engine starts), so check as the key is turned on.

Here is the replacement pump:

http://idparts.com/catalog/product_info.php?products_id=585

Soem cars run fine without the lift pump, some run poorly and some won't run at all. Its strange.

I really doubt that there would be a difference between hot and cold starts with a failed lift pump, so it may be another issue, but if you have a failed pump, you might as well replace it and eliminate that.

I can personally attest that my car DOES NOT run at all without its lift pump working.

--Nate

After reading more I did all of this last night actually. I started by checking the voltage at the plug to the pump. It spikes up to about 12-12.5 V for just a second when the key comes on, like it should i assume. Then for the hell of it I pulled the line to the filter from the tank, and stuck it in a small plastic bottle. Key on made no fuel come out what so ever. So I'm going to pull the pump out tonight and check it out.

I got in it this morning and she fired right up when cold no problems what so ever. And will again around lunch and again when I need to go home this afternoon. This is whats blowing my mind.

Thanks for your help Nate,

Evan

Maybe once the pump heats up and quits pumping. Your lift pump is clearly bad so you should just replace that anyway.

I wouldn't be too quick to condemn any part until you are certain that it isn't working. Some of the PD BEW's will run fine without the lift pump (with some of the lift pumps the tandem pump is able to still suck fuel through the in tank lift pump & you can have a bad lift pump & never even know it). Any easy test to check out both the lift pump & the tandem pump is to do a "Diesel Purge" procedure. Advanced Auto parts sells diesel purge (many of the on-line vendors in here do also). You get some clear tygon hose that will fit inside the black rubber hose that you disconnect off of the filter. The line that feeds the tandem pump & the return line from the PD injectors goes into the can of diesel purge. The two lines from the in-tank lift pump at the filter & line from the thermostatic tee that returns to the tank can get jumpered together. You can run the car at idle for about 40 minutes off of the can of diesel purge. It gives the injectors a good cleaning; and you can look at the flow returning from the injectors to see if the tandem pump is flowing & you can also see if the lift pump is flowing. The tandem pump also has a pressure connection to hook up a gauge; but as long as the PD injectors are getting some fuel flow, the car is going to run (even if the pressure is low). Do you have access to Vagcom? If you do, check for codes. One of the things that will affect how well these engines start is the timing. There is a good how to video on myturbodiesel.com on how to adjust this. I found my "Torsion Value" in Vagcon at -1.5 & advanced it to zero but the car was very hard to start; I set it back to -.5 & it started fine. There are other sensors like the engine coolant temperature sensor that will affect how the car starts. You really need to look at these things with Vagcom though to see if the values look normal or not.

So after calling around and pricing pumps I decided to go with TheTDIWagonGuy's replacement pump only. Car runs and starts just fine now.

Thank you for all the responses and to TheTDIWagonGuy http://www.defender-tech.com/ for selling just the pump! It is so much cheaper, and anyone with any sort of do it yourself mechanical knowledge can replace the pump with no problems what so ever. The hardest part was getting the old hose off and the new one on. If I had to do it again it would be a 15-20 minute job TOPS.

Evan

Well I spoke to soon. The car starts better, but still not all the time.

Drove to a conference today. When I decided to leave (maybe 2 hours) the car cranked for a long time before starting. Went and got some food (maybe an hour) car cranked for a long time and then started when I hit the throttle... Putting a new fuel filter in it now. we will see.