2000 TDI Golf won't start at random. Any help appreciated!

2000 TDI Golf won\'t start at random. Any help appreciated!

Hi all,

I had orignially thought this was related to the anti-shudder valve, but it no longer seems to be. As far as I can tell it is completely random.

I had a dozen failed starting attempts this morning when it was cold. The car sounds like it starts immediately (on the first turn, as usual), but only runs for half a second then shuts off. The first couple of times it took a second to shut off, after that it shut off immediately after starting.

I fiddled with the anti-shudder valve, working it open and closed, tugged on all the vacuume hoses, all while attempting to restart the car. All of a sudden it started perfectly, and it appeared that there was no problem. But I can't think of what I did to make it start.

It started on the first try after work. I drove it home, and shut it off, and restarted. It started perfect. Shut it back off, and tried to start again. The problem was back: it starts, runs for 1/2 second, and immediately shuts off. No amount of retrying will get it to start.

So I fiddled with everything, got it to start again (who knows why?!), and let it idle for a minute. Turned it off, tried to restart, and it won't start. Now it sits in my garage, not starting.

I'm frustrated! What can I do?

I have small bubbles in the fuel line, is that normal? I don't think it's a fuel deliver problem since "all of a sudden" it starts working.

I cannot find any vacuume leaks. I pulled apart the intake manifold, and it is clean except for a mild coating of soft black oil which wipes right off with my finger. I don't believe I have intake clogging problems.

What is "relay 109", could that have anything to do with it?

Please help!

Re: 2000 TDI Golf won\'t start at random. Any help appreciated!

How many miles Aaron?

The dealer tried to manually show me how he could duplicate the valve closing when I went to pick up my car but, when he tried it with the crud removed it would just die immediately.

I think I had so much crud in there that the valve was sticking partially open to let in enough air to idle. Yours might not be that built up so your valve is closing more completely.

With the engine running go and look how the little lever on the back of the valve (where the plastic hose connects to the intake manifold) is oriented. The next time it won't start, leave the key on and go and see if it's opened (same position as when you saw it running last).

If it's open then you have another problem.

Re: 2000 TDI Golf won\'t start at random. Any help appreciated!

Yep, I checked and the valve is always open. In fact, I held it in the open position while trying to start, and the problem remained the same.

I just went back into the garage, and the car wouldn't start after several tries. I waited a couple minutes, tried again, and it started. I shut it off, tried to start again, and it no longer starts.

Very random, no explanation or pattern. Well, except that it's getting progressively worse such that it usually will not start anymore unless I swear at it and wiggle hoses and other parts for 10 minutes first.

Aaron

Re: 2000 TDI Golf won\'t start at random. Any help appreciated!

Here's the list from Bentley's for a no start condition:

1. Cranking speed too low or will not crank (repair starting system or change/replace battery)

2. No fuel or wrong fuel in the fuel tank (Verify sufficient fuel of correct type in tank.)

3. No voltage at fuel cut off valve on injection pump. Fuel cut-off valve loose or faulty. (Valve should click each time ignition is turned on and off. If not, check for voltage at connector. Replace a faulty solenoid.)

4. No voltage at glow plug bus or glow plug(s) faulty

5. Excessive air in the fuel system

6. Injection pump not delivering fuel

7. Injection timing incorrect

8. Faulty injectors

9. Engine mechanical faults (test compression)

10. Faulty injection pump

11. Fault in engine speed sensor (test sensor at connector)

12. Fault in ECM or other engine management system component

Since the engine runs when it does start, it could be your battery getting weak. Frequent starting like you're doing in these tests is draining the battery and it isn't getting a chance to recharge adequately. If it sits long enough, it may recover enough to start later. Check battery connections for being clean and tight.

If you have a battery charger, put it on and see if it charges the battery any. Then after it reaches full charge (or near so), disconnect charger and try starting. If you haven't jiggled anything around doing this, then it shouldn't be anything else.

Check other electrical connectors mentioned above for being properly connected.

Re: 2000 TDI Golf won\'t start at random. Any help appreciated!

Hey thanks for this list from the manual. Let me attack these one at a time and see if it gets us anywhere.

1. It cranks very fast, every bit as fast as a gas engine. In fact, when I say "it doesn't start", that's not entirely true. It completely starts, but then immediately shuts back off again within 1/2 second.

2. I have 3/4 of diesel from Exxon in the tank - when it does run, it runs fine on this fuel.

3. I'm not sure where the fuel cutoff valve is. I hear clicks when I turn the key. When the key is in the "on" position, the pump should be pressurizing the fuel at this point, right? Can you point me to the cutoff valve and I'll listen while somebody else turns the key?

4. Car starts frequently on the 1st try of the morning, and the glow plug light stays on for 5 seconds or so in the AM. Additionally, the top of the valve cover is warm to the touch. I'm certain the glow plugs are OK.

5. I see a stream of tiny bubbles in the fuel while the car is running. They collect into a larger bubble when the car is shut off. Is some of this getting sucked in where it doesn't belong? How could I remove it? Is this "too much" air? Seems like everybody has a few traces of bubbles on the "in" side after the fuel filter.

6. Any way to test the injection pump? Maybe it's not clicking on when it should, but when it does, it stays on until the next restart? Could this be a possibility?

7. Car runs great after starting, I rule out timing.

8. I rule out injectors for the same above reason.

9. It's a 2000 MY with 40K miles - I doubt compression. Car pulls like a beast once it starts

10. Isn't this the same as 6? Or are they two different pumps?

11. Engine speed sensor - as in RPMs? I notice that when I try to start the car, the RPM gauge jumps to the normal 900 RPM idle, then falls back down to zero when dying 1/2 second later.

12. Would an ECM fault be detectable by the dealer vag-com tool? Maybe I'll have it checked . . .

I don't know if this information will narrow down my problem or not. I believe it's an electrical issue, since the car will start and run perfect once, then start and immediately die the next time. If it were a gasoline engine, I'd suspect that the choke is cutting off prematurely before the engine gets a chance to run on its own, that's what it behaves like. Start, then immediately die.

Oh, BTW, I have an UPsolute chip installed. But it's been installed almost since new without causing this problem according to the previous owner, so I don't suspect it.

Thanks again!

Aaron

. . . now if I can get either the Golf or the Q45 running, I can get to work tomorrow morning . . . I don't know which will be more difficult . . .

Re: 2000 TDI Golf won\'t start at random. Any help appreciated!

Hi, sorry for all the posts - I'm just desperate!

Here is a commonality! There is a "thinger" on a metal clip attached to the middle/back of the intake manifold. It has three vacuume hoses attached to it, and a grey cap on top. The "thinger" has VW/Audi symbols on it, but the grey cap says "Made in USA" on it. Weird, huh? What the heck is that thing?

Anyway, whatever it is, if I tap it and wiggle it, then the car will start. It is currently idling (woohoo!) I'm almost tempted to leave it running so I can drive it to work tomorrow morning.

If my description of the "thinger" proves useless, I will take a picture of it and post it for y'all to review. somebody has to know what it is.

Aaron

Re: 2000 TDI Golf won\'t start at random. Any help appreciated!

If it is #2 in this picture, it is technically called a "thinger". Common name is "Intake Manifold Change-Over Vacuum Control Valve".


It controls the "anti-shudder valve".
It is supposed to close for approximately 3 seconds when the engine stops and reopen once the engine stops. If it doesn't no air goes into the engine.

It sounds like the control valve is sticking. Vacuum is applied to the the "anti-shudder valve" and chokes off the air to the engine.

[ July 31, 2001: Message edited by: MIGOLFGLSTDI ]

Re: 2000 TDI Golf won\'t start at random. Any help appreciated!

my wife had the same problem with her Jetta - it was her key - something to do with the signal it sends, anyway it worked

Re: 2000 TDI Golf won\'t start at random. Any help appreciated!

As a 2000 it does have the immobilizer, but I wonder if the immob. light would be flashing then?

Re: 2000 TDI Golf won\'t start at random. Any help appreciated!

Yep, the thinger I wiggle to get it to start is indeed the Intake Manifold Change-Over Vacuum Control Valve. That almost sounds perverse . . .

When the engine is shut off, the anti-shudder valve is in the open position. When I turn it off and immediately run around to the front to look, I see it opening after having just been closed.

Just now I am unable to recreate the problem, it is starting reliably. I am going to bring both keys to work to see if that makes any difference (for possible immobilizer issues). When the problem resurfaces (likely tomorrow), I will see if the anti-shudder valve might be malfunctioning, and closing immediately after the engine starts, causing it to shut off.

Thanks for the assistance, and I will post back tomorrow!

Aaron

Re: 2000 TDI Golf won\'t start at random. Any help appreciated!

If the vacuum valve is malfunctioning like I think it is, it works properly at shutdown. But it is stuck in the "apply vacuum to servo" mode. Vacuum bleeds off and the valve opens. Then you start up the vehicle and it takes a few seconds to build up vacuum again. This gets applied to the servo (because the switch is stuck) and the valve gets pulled shut again. Thus the engine dies.

Get a new vacuum valve.

Re: 2000 TDI Golf won\'t start at random. Any help appreciated!

Sounds like an Immobilizer problem to me too. Time for a VAG-Com check