1.9 TDI Starting Problems: Get Help Here!

hi all,

It's happening again; my car has developed another problem: When I start my A3 TDI (engine number AGR, 66 kW, manufactured in 1997) in the morning, it starts perfectly. However, after a few seconds, it sounds like it's about to stall, and at the last moment, the idle speed increases... This happens approximately every 10 seconds, repeated 3-5 times in a row.

'If I let it run for about a minute, everything seems to be okay. It just sputters during those idle fluctuations. The problem doesn't occur if I start it when it's already warm.'

'Any ideas? Thanks in advance for your help!!!'

Best regards, Wolf

Hi.

While I don't have a specific idea about the cause, more information might be found in the error log.

If it's not possible to read the data initially, you could try starting the process without gas during the bagging phase.
Normally functioning TDIs aggressively increase the engine speed as soon as it drops below idle level, which allows you to easily start moving using only the clutch and foot brake, even on inclines.
(Try it out when it's running normally to get a feel for the power it delivers.)

If your car tends to stall easily after starting cold, it's likely due to a lack of fuel (possibly a faulty fuel cutoff valve?).
If it still has power, the problem might be related to the speed sensor.

Just throwing out some ideas...

Thanks, Ulf. I've just tried starting it a few times now, without...
'When I give it gas, it slightly increases the RPM, but doesn't necessarily jerk violently – and it barely hops at all...'

and now what? should I drive to the friendly place?

best regards, wolf

Hi.

Quote:

and now what? Should we go to the friendly place?

Hm, I would rather look for someone competent, as that is often more useful than just being friendly .

Given that your problem seems quite unusual, there probably aren't any standard solutions available for it.
It's all the more important to read the error codes. Hopefully, there will be something stored in the memory, and hopefully, it won't lead a clueless mechanic down the wrong path.

Please provide the text you would like me to translate from German to English. I will then give you only the translation, without any explanations.

Okay, so, this morning I unplugged the connector that's located on the right side of the thick hose (when looking from the front) on the TDI engine, and then I started the car – and guess what, no more sputtering! Now what?

'Today afternoon, I was driving when suddenly the oil light started flashing and the engine turned off. After 5 seconds, it was working again. I added some oil.'
I see, but everything is okay... what was that?

help meeeeeeeeeeeee!

Hi.

Item number 1 indicates a problem in the temperature sensor area.
Before replacing it, I would check the wiring harness in its vicinity for any bare spots or areas of chafing, sharp bends, etc., which could indicate cable breaks.

Number 2 --> mysterious. Reading the error memory is becoming increasingly advisable.
Here's a tip: very strange error patterns often have mass-related issues as their cause.
But even finding the mass points is often not that simple, let alone the *%&/$§%-mass splices in the cable harnesses .

'...yesterday, just for testing purposes, I disconnected the plug from the EGR valve... the starting problems were also gone. Furthermore, the jerking at partial throttle is gone, and the black smoke when accelerating has also decreased...'

My car is now at the Bosch service center, hopefully with competent technicians... I'll post the results!

c u, wolf

Okay, I just picked up my car from the Bosch service center – of course, the error memory was empty except for the EGR (exhaust gas recirculation) message; I've now had it decommissioned.
'The pump settings have been adjusted (dynamic something), and the LMM (mass airflow sensor) has been replaced (at a special price). He's not making as much noise now...'
Let's see.

Regarding the oil pressure light, nothing particularly unusual could be determined... it's always the same issue.

Let's see!

Did the Bosch service technicians disable your EGR valve?
When I asked for a more 'elegant' solution to do this (something that looked better than just using a hose and a screw), they immediately started talking about how 'we are not responsible for engine damage, you have to do that yourself'...?!

greetings
I'm sorry, I can't translate that word because it doesn't seem to be a real word in any language I know. It might be a typo or a made-up word. Could you please double-check the spelling?

Hmm... I wouldn't trust a workshop that does something like that, not even an inch.

By removing the catalytic converter (AGR), the vehicle loses its operating permit (ABE), and driving it on public roads becomes illegal.

If someone does this themselves, being fully aware of the situation, and a workshop performs the work without providing any information or only talking about engine damage, I would almost consider that criminal.

Apart from that, the fact that they are unaware of the ABE requirement makes me question what else they might not know, purely from a technical standpoint.

Just a few thoughts on the matter... this isn't to say that you should disable the EGR system, but rather that you should be aware of this fact. And a workshop should at least mention it.

Best regards,

January.

Hey everyone,

I probably should have mentioned that the workshop manager at the Bosch service center is a long-time friend of mine? It's clear from the operating license requirements and so on, but their mechanics are really skilled and know what they're doing. I'm not the first one who's had them disable the EGR system.

Best regards from Austria, Wolf.

Okay, that sounds different. I just thought my reaction was a bit harsh, and I also have some doubts about whether they really understand the subject matter.


greetings
I'm sorry, I can't translate that word because it doesn't seem to be a real word in any language I know. It might be a typo or a made-up word. Could you please double-check the spelling?