A3 Strange start up problem

[EmeraldTDI]

Hey folks,

My 97 Jetta TDI is having problems starting. I'll put the key in, the battery seems fine (gauges, lights, radio, fan all working fine), but I turn the key and absolutely nothing happens (no crank at all, so I conclude glow plugs are NOT the problem), just silence from the engine.

So, I pushed it, popped the clutch, it starts fine. I've had to do that twice since yesterday.

I took it to a trusted mechanic who tells me he can't see anything wrong with the car, he says the battery is fine, the starter is fine...that bothers me, because the car was having difficulties, SOMETHING must be causing the problem...

Anyone have any experience with these curious symptoms?

I have already replaced the ignition switch under recall warranty (plenty of info in other posts on this), so I don't THINK it's an ignition switch problem (especially since, as already mentioned, everything else works when the ignition is turned except the car won't start).

 

[DocSoot]

The clutch pedal interrupt switch might be the problem. Since your starter won't turn over but the engine will push start and run, check for loose connections or bad wires and the switch.

 

[rdkern]

If you can use cruise control, the clutch switch would not likely be the problem.

I'd clean all of the grounds - including the big one from the battery to the frame, all of the little ones that are under the battery and firewall, and clean up the contacts to the starter motor. After cleaning, of course reattach and tighten nicely. Give it a try - might work.

 

[Toronto_Vento]

Just because you get radio power, etc, DOES NOT mean that your battery is okay. Only way to test a batt is under load. If you have a multimeter, you can test the batt by measuring the voltage while someone else tries to start the car. Diesel engines tend to take a lot of energy to get going, so a good battery is essential.

Honestly, though, if you are telling me that the engine does nothing (I assume you hear a single click when you turn the key to try and start the car), it is the starter. You can try cleaning the terminals, etc, but for the age of your car, it wouldn't be a surprise to need a new starter. Remember, starters have nothing to do with mileage. Someone with high highway miles will probably go longer with the original starter, compared to someone who is a city driver and needs to start the car a few times per day.

 

[EmeraldTDI]

Thanks to all of you for your insights.

The mechanic confirmed that he tested the battery, the starter, the connections, he said "I looked for something to replace to make some money, but there's nothing I can do, it's fine. We started it a bunch of times through the day, no problem." In fact, he didn't even charge me for the time he put into the testing.

In light of all your suggestions and coupled with the mechanic's view, I THINK the most reasonable conclusion is that some grounds or wiring were just loose enough to have caused the problem without being obvious yet got tweaked by the mechanic and is thus ok... sound reasonable?

Oh, wait, one more note - even though I don't think it has anything to do with the glow plugs, in the summertime I do tend to forget I drive a diesel engine and turn the key without waiting for the glow plug light to go out (in the winter I've never forgotten, and through two winters I've had absolutely no problem whatsoever with winter starts. Mind you, I've waited 10 seconds for the glow plug light to go out on some cold mornings, but once it's out, the engine turned over smooth and fast every time, reliable as the sun coming up in the morning).

What damage can cranking before the glow plug is out in the summertime cause over time?

Thanks again guys - I couldn't/wouldn't own a diesel engined car without the support of this knowledgeable community.

 

[jck66]

Does the A3 have a clutch switch that interrupts the starter? The B4 does not.

 

[Toronto_Vento]

No damage for cranking right away. They actually don't come on in the summer. The indicator is just that in the summer...something which lights up as the ECM checks the system. No biggie to starting the car right away.

 

[EmeraldTDI]

OK, an update.

Last night it didn't start. I jumped started it. This morning it started but hesitatingly. After work it did not start at first, but I kept the key turned...it cranked ever so faintly once, then a second time a little stronger, then I tapped the throttle pedal and finally it started...

If there is a correlation between the wet weather and the problem, how would I fix it? Up until the last few weeks, I've never had a problem with this car starting in any kind of weather.

Thanks again for any insights...

 

[rdkern]

I'm going back to the ground wire possibility. There are a bunch of them in there, under the battery is one or two connections - on the block/tranny, as well as some that connect directly to the battery. I'd try to remove, clean, and tighten all grounds. It can't hurt, and, based on what your mechanic did the prior time, it may be the problem. He just may not have actually cleaned anyathing - just tugged a bit here and there.

 

[EmeraldTDI]

OK rdkern, I'll give that a try, thanks. I'll provide some feedback soon.

 

[oldiesel]

my A3 recently had a similar starting problem and it turned out to be a bad connection where the positive cable attaches to the large post on the solenoid on top of the starter.The nut was not loose but corrosion had worked its way in and once i dicovered with a test light that there was power at the starter end of the cable but not to the stud it was attached to while someone turned the key for me i thought it would be a simple fix,however the nut was corroded on the stud and was very difficult to remove as it is VERY easy to break the end of the solenoid if too much force is applied.It took me a good hour to remove the nut,finnaly had to cut thru it with a dremel. its worth checking especially if you can catch it when its not starting. Good Luck