Stalls, won't start without ether, recurs, can't find issue in FAQ

Sorry if this issue is already discussed, I could not find it.

Last week on one of the cold days, I went out and started the bug to warm up, went inside to get ready for work, came out and found the car not running, but all electrical was still on. Turns over fine, but won't start. Took another car to work.

Later, when the weather warms up, still turns over fine, but won't start. I guessed bad fuel pump or some other fuel problem. Towed to mechanic. Mechanic tries everything, good fuel pressure, can't find a reason for no start. Gives it a shot of ether, it starts and stays running. He apologized for not finding cause, but it runs anyway. Started fine for the next few days.

This morning, not as cold, same thing. Started the car to warm up, go inside, come out 10 minutes later and it's not running. Turns over but won't start. Run to store to get some ether, give it a shot, starts and stays running fine, like nothing happened.

Any guesses?

03 TDI Beetle 5 speed manual, 310,000 mi

I understand that the use of ether is not recommended. Please ignore that part of the thread and focus on the symptoms.

Glow plugs are working as expected as well.

If the glow plugs are working you CERTAINLY do NOT want to be using ether. There is a whole thread on cold weather starting problem trouble shooting. ( http://forums.tdiclub.com/showthread.php?t=199398 ) - it's a sticky.

Off the top -
Good battery ? (Used to be Group 48, that's probably an H6 now - do not use Group 47)
proper oil ? (5w40 diesel rated, 0w40 should be acceptable)
non-biodiesel properly winterized ?
good fuel pump ?
Timing set properly ? ( see guru to get set corrrectly) ALH's were tested to -40 in interior AK and Canada, so even if it doesn't make much interior heat, it WILL run.
Fuel pickup in tank not clogged (this was a problem in early years, it can be drilled out or replaced with the version that ends in "H" )

I'm sure the real mechanics will be by to give you some real help.

When is the last time you've changed your fuel filter? A dirty fuel filter combined with was crystals in diesel from the cold, will cause no fuel to get into the injectors.

Just for ****s and grins, what color is the 109 relay?
If it's black change it to latest which I believe is grey and see what happens.

The vehicle starts ............. he said that twice! (excluding the ether starts).

I assume the car is the 03 NB.

At 310,000 miles:

1. Possibility the IP is leaking fluid and losing prime.
2. Fuel gelling in the filter due to not using winterized fuel or not anti-gell additives
3. Air entering the fuel system at the Thermo T on the fuel filter. Seems some NBs never had those style filters ... maybe the 03 did... easy to identify.
4. Possibility that the 109 Relay is acting up as it will warm up from ambient once the ignition is turned on. (contraction and expanding due to temp change)
5. And as suggested, the thingy in the fuel sending unit in the tank could be clogging, gelled with waxed fuel, etc.

I suggest that when you first start the car when it is cold, after a few seconds, rev the engine up to about 1500 RPMs for about 3 to 5 minutes. If the engine does not quit after the rev followed by just idling, I suspect the issue is #1 above.

Thanks guys. I've got a few things to try. I'm going to start with replacing the sending unit and filter.

You probably don't need to replace your sending unit, most people just drill out the check valve.

What recent maintenance, if any, was performed?

JB05 said:

What recent maintenance, if any, was performed?

Click to expand...

None, just oil changes. It's been running fine since the 300,000 timing belt maintenance, 10,000 miles ago.

Were any wires dislodged/moved or touched during the oil change? The reason I ask is I did just this when I changed my t-stat last month. Car would not start immediately or would stall in traffic. The culprit turns out to be the crank shaft position sensor whose delicate wires I had moved causing a possible break. It's OK for now, but waiting for a good time to change the sensor which is in a very tight spot on my BEW.

I'd start with a simple fuel filter change.

I'd put a bottle of PowerService Diesel 9-1-1 into the tank. Possible gelled fuel if it's been a while since you filled up.

Make sure sending valve is drilled out. Bleed fuel injectors and then the free part of diagnosis is ruled out. That will always be a nagging and costly question mark unless it’s done. Mine just gave me grief I wasn’t expecting and cost me dearly.

The fuel pick-up can get partially restricted or clogged. But I would troubleshoot this as air intrusion to the fuel system. Dumb stuff would include the injector return tubes.