Stuck Glow Plugs - Audi AEL: How to Fix

Hi, my AEL is having extreme cold start problems.
After playing the organ for a long time, it starts up, but then briefly emits white/gray smoke.
Warm or lukewarm is fine.

The friendly mechanic was supposed to replace the glow plugs, but the master mechanic called me to say they couldn't do the job because the plugs were so tightly stuck that there was a very high probability they would break off.

To avoid incurring further costs, I decided not to have the repair done.

According to Audi, the only way to remove the spark plugs is to disassemble the cylinder head.
Is that really the case, or are there other approaches that might involve less effort?

Unfortunately, I only had the timing belt replaced last November, and I'd really like to avoid incurring those costs again.

Thank you for the tips.
Cheers!
Thomas.

Hello,

Cold start problems with the current temperatures ?

I'd venture to say that the candles are not to blame. My TDI also starts spontaneously, even at around 0 degrees Celsius, if I turn the key all the way immediately. At most, it then runs a bit louder.

I suspect there's a different issue; for example, I see the temperature sensor for the coolant temperature right at the front.

I'm leaning towards a misadjusted injection timing during the timing belt replacement. As long as it's cold, the glow plugs compensate, but now that it's getting warmer, the problem is becoming noticeable. The timing should be set on the early side, or even slightly too early.

Good evening.
So, at +4 degrees Celsius, I still have to fiddle with it until it finally starts, as described above.

After the timing belt replacement, the injection timing was checked twice by a trusted mechanic. Both the static and dynamic timings were verified. It was adjusted to the earliest possible setting.

The workshop believes the glow plugs are the culprit. Of the 2 they removed, both were defective.

certainly:
The engine is smoking black, but it has full power (it has a BB-Motorsport chip).
The air intakes, turbocharger (pressure test), fuel injectors, and pump have also been checked. The EGR valve was replaced because it was completely clogged with carbon deposits, but it didn't improve the situation.

The workshop is attributing the smoking to the chip, because it's also running very well.

However, before the change of the spark plugs, it didn't smoke as much, and it started up much better...


Wie gesagt, die Einspritz-Zeitpunkte wurden von der Werkstatt nach meinen Reklamationen nochmals geprüft. Ebenso die restlichen Komponenten, alles OK lt. Audi-Hahn...
Bis ebend auf den Chip wegen dem Qualmen und die Glühkerzen wegen dem Kalktstart. Says Audi...

Could there still be a causal relationship somewhere?

Thank you for your input.

Greetings.
Thomas.

Hi,
If the engine started well before the timing belt replacement, then there's likely a causal connection, right?
Check the valve timing, even if the injection timing is supposedly correct.
Or get it checked somewhere else.
If two spark plugs have been replaced and are now working correctly, then it should at least start immediately on those two cylinders, right?

Best regards from Berlin.
Olli.

"The problem with the stuck glow plugs is a common one. The defective glow plugs are particularly difficult to remove because they are heavily clogged and cannot burn clean."
You can try spraying WD40 on the threads for a few days, then warm up the engine thoroughly, and try to loosen it. Most spark plugs break at around 25 Nm. You have to do this by feel.
If the spark plug breaks off at the threads, which doesn't happen very often, you have to remove the head and drill out the rest of the plug because it's impossible to prevent debris from falling into the combustion chamber while drilling. This is a very complicated and dangerous process, as it's easy to drill in the wrong place. If the spark plug breaks off at the tip, which protrudes into the combustion chamber, there's a possibility of shooting out the remaining piece with the engine running. Wrap a few rags around the threads and give the accelerator a few strong pumps. It's not the most elegant method, but it works. Another method is to cut a thread into the remaining piece of the spark plug (drill a pilot hole first, but don't drill all the way through) and then screw in a threaded rod and carefully pull it out.
I hope I have helped .

Still, I don't believe in those glow plugs and the difficulty starting in these temperatures.
The AEL had two different engine control units (ECUs). One version spins up to 1000 RPM (like mine), while the other spins up to 1200 RPM (like my friend's non-quattro version) when reading the injection timing.
Therefore, there are two different values for setting the injection start, which I believe are 45 and 60, depending on the version of the control unit you have. Perhaps there was some confusion.
Have the fuel injectors been checked yet? They could also be responsible for the black smoke if they're just leaking instead of spraying properly.

Hi everyone.
Okay, I know that the AEL 2 has two different control units. However, it seems to be dependent on the year of manufacture. What's new to me is that this also affects the fuel injection timing. I wonder if my Audi mechanic knows this as well? I've already been to two different master mechanics...

The nozzles now have 34,000 km on them; I checked again. They were previously refurbished by Henzo. So, they should still have a few more kilometers left in them...

The smoking issue is getting worse. Therefore, I hardly use the AEL anymore, but luckily I have an alternative vehicle.

He's still performing very well, at least in terms of feeling, so I can't complain about his performance.

The train is also quite fast, reaching a speed of 200 km/h. However, there's a huge wall of fog behind it .

I probably still need to consult another workshop. Better safe than sorry.
I'll keep you updated, but it might take a few days. I'm completely renovating the whole house right now.

Until then.
Cheers!
Thomas.

EDIT by MOD.

Okay, that's enough!! 235 or 240 km/h with a standard AEL . You can post something like that on Motor-Talk. Not here.

Well, you can easily test whether the candles are working or not using an ammeter.
I do it that way too.

I'm connecting a voltmeter to the ammeter, and then disconnecting the spark plugs. Working spark plugs should then draw a current of approximately 20A - which means they are functioning (that's my theory...?).

"The replacement of all the candles is also typically done every 4-5 years, which is probably why they seem to come out 'easily'?"

I also have a car that is well-maintained, with new spark plugs, but it starts poorly when it's cold.
The second vehicle is no longer being serviced, and the engine starts immediately even below 0°C without preheating, although it might produce a bit of black smoke (theoretically).

Sure, here is the translation of the text from German to English:

"Hello"