Fuel Filter: Starting Problems? (ATU)

Hello!

I had already reported about my starting difficulties in the thread 'Relais 109 where the 1Z is located'.
Last week, I was at ATU, where the fuel filter was also replaced. Since then, the car has been extremely difficult to start.
I was reminded of posts about the fuel filter from ATU and just reread them again using the search function.
At that time, some people (Martin L. and Stukov) were only talking about a loss of performance. Could it be that this is now also part of my starting difficulties?
'Another question for Stukov: How did you identify the defective filter back then?'
Did anyone else experience problems with ATU filters?

I've already replaced: spark plugs, relay 109, and the battery. I'm really at a loss now.

Best regards, D.

D. wrote:

... at ATU, where the fuel filter was also replaced...

Hi!

What else was exchanged/repaired?

Best regards,
Uwe

Otherwise, only the oil was changed.

Best regards, D.

Hi!

Well, after an oil change, everything should actually function normally.
If specific problems or changes occurred after the filter change, then I would look for the cause right here. In previous posts, the ATU filter was identified as the culprit. Just to be on the safe side, I would simply install a new one (they're not that expensive), that way you're sure and can prevent further trouble.

Best regards,
Uwe

'Hi, I was experiencing significant performance issues, especially when the engine needed to work hard and consume a lot of fuel. The filter was then replaced again with another one from ATU. Eventually, I had the idea to get an original filter, and that's when the symptoms disappeared.'

The original one costs about twice as much (around 30 euros) as the one from ATU, but I would never buy anything other than the original again.

Hello D.,

If your car has trouble starting after being parked for a while, I would check the hose between the diesel filter and the ESP (Electronic Stability Program) for any air leaks.
Possible leaks:
- Hose connections on the filter.
- Seal(s) of the T-return valve in the diesel filter.

Best regards, Rainer.

Hello everyone!

Thank you for your advice.
I went to ATU today to return the filter. I also brought printouts of some online discussions. However, they didn't want to hear anything about it.
I was then referred to the 'expert.' He immediately took a closer look at the car. He said it must be the glow plugs, searched for them, and then said, '...ah, this is a direct injection engine, it doesn't have glow plugs...'
Hello?
Where am I?
My car is back at the mechanic's shop overnight.
I'll post the results tomorrow - hopefully, I'll survive it financially.

Best regards, D.

Okay, I would suspect a faulty return valve.
Possible causes include:
* Poor filter ventilation.
When the engine is warm, it should be harder to start than when it is cold.
Then it could be the check valve.

Best regards,

Hi!

I know these symptoms all too well.
I made the same mistake back then and bought this inferior filter.
The result was a loss of power and the formation of air bubbles.
Got the original [item] and the problems disappeared.
Was sagt uns das? Car Dead.


Cu: Marko

Rainer K. wrote:

Hello D., If your car has trouble starting after being parked for a while, I would check the hose between the diesel filter and the ESP (Electronic Stability Program) for any air leaks. Possible leaks: - Hose connections on the filter. - Seal(s) of the T-return valve in the diesel filter.

...and the Simmerring on the drive shaft for the ESP (Electronic Stability Program) - a long air bubble in the intake hose, especially after a long period of inactivity, particularly when the front of the vehicle is pointed uphill!!!!!

Best regards, Christian.

Thank you for this troubleshooting guide!!
My fuel filter (the real one with 3 Fs) is due for replacement soon.
Actually, I usually like going to ATU and I even get discounts there, but after reading this, I think I'll probably avoid it.
What about air filters from ATU?
Is this also terrible?


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

'Hello'

D. wrote:

I was then referred to the "expert." He then immediately took a closer look at the car. He said that it could only be due to the glow plugs, searched for them, and then said, "...ah, this is a direct injection engine, it doesn't have glow plugs..."

.

Hi.

You don't really have to take that so seriously, especially when it comes to the "expert" knowledge of a "master."
After all, it was about the fuel filter, not the glow plugs .

It might have been even funnier if you hadn't immediately run away to the friendly place .

So, I got the air filter as an original part. It costs 15.35 EUR plus 16%, which is reasonable.
I also initially used the original fuel filter, but ATU refused to install it because of the supposed warranty.
Now I have the original part again, but ATU is not reimbursing me for it, because they claim they've never heard of this issue before. They were trying to offer me a replacement part.
Besides, I received a new temperature sensor from 'friendly' and now I'm enjoying my car again.
Unfortunately, the cat tree is about to collapse due to rust, so I will probably replace it this week.
Best regards, D.

Hi,

@D.:
You mentioned that you received a new temperature sensor.
Is that the sensor that reports the coolant temperature to the engine control unit (for preheating and similar functions)?
What does it cost?
Did it make any difference for the cold start?
I'm also experiencing some minor issues with the AAT.

@ Markus!

Temperature sensor with part number 357 919501 A, priced at €17.50 net, plus 16% VAT.
I think that might have made a difference. But today, at minus 3 degrees Celsius, I noticed that the car starts better in sub-zero temperatures than when it's just above 0 degrees.

Best regards, D.

Hi D.,

I also have the same impression: it starts very well in temperatures below freezing, but performs worse (mostly) at temperatures between 5 and 10 degrees Celsius above zero.
You're probably not able to clearly identify the effect of the fuel pump replacement, since you also changed the filter at the same time, right?
Since the price is unusually reasonable, I might try that out sometime.
However, I have another suspicion: After a prolonged period of inactivity, an air bubble forms in the diesel line in front of the ESP (Exhaust Gas Recirculation system).
However, since it starts well in cold weather, it's probably not the cause of the problem, is it?