Kaltstartproplem beim 1Z nicht gelöst *heul* | Posts 112+

Hi,

hab mal eben bisschen die ESP betrachtet, um zu verstehen was zur Justierung des Mengenstellwerks zu verschieben ist (war mir noch nicht ganz klar). Wenn ich es richtig sehe, dann verschiebt man nicht den Deckel ganz oben, sondern die ganze Einheit ab Höhe Zulaufleitung (die 3 Torxschrauben hierfür liegen etwas tiefer als die oberen für den Deckel). Die Dreiecksschraube ganz oben ist die 4. Befixing screw for the entire upper part)

Interestingly, there are two vertical markings (possibly rice needles??) on the top and bottom sections on the right side, and a single vertical line on the left side of the pump. However, the lines don't quite align: the upper one is further to the right! Also, the four screws (especially the triangular ones) don't appear to have ever been loosened.


@Ulf:

I think you should charge money for your tips .
Your assumption that tuning can be achieved by adjusting the quantity setting is correct again, or do all three of you have three longitudinal bars on your ESP? My father doesn't!

I think I need to give my previous owners a piece of my mind.


Best regards, Christian.

Hi Christian,

It looks like someone has already tinkered with it before, because markings are usually not found on these pumps.

Hi Christian,

haehnlein wrote:

If I understand correctly, you don't move the lid at the very top, but rather the entire unit starting from the height of the inlet pipe (the three Torx screws for this are located slightly lower than the upper ones for the lid). The triangular screw at the very top is the fourth fastening screw for the entire upper part.)

Yes, that's correct.

Quote:

Interessanterweise sind zwei senkrechte Markierungen (Reisnadel??) auf Ober- und Unterteil rechts und eine senkrechte Linie links auf der Pumpe. Die Linien fluchten aber nicht ganz: die Obere ist weiter rechts!!!! Außerdem sehen die vier Schrauben (besonders die Dreieckss.) nicht danach aus als hätte die nie jemand gelöst!! . . .

That's probably the case.

Quote:

I think I need to give my previous owners a piece of my mind.

Hmm, in your "special" case, I can also imagine that increasing the fuel pump's capacity wasn't primarily intended as a tuning modification, but rather to improve starting performance, because it also mechanically increases the amount of fuel delivered during startup.
If you revert this change, the starting behavior could become even worse – unless you correct it again using VAGCOM (fuel injection quantity adjustment).

I would definitely start by checking the engine temperature sensor using VAGCOM. In my opinion, it's a likely culprit when experiencing noticeable "temperature-dependent" starting problems above the glow plug ignition temperature.

To prevent busy TDI drivers like you from getting bored, there's a new technical article about the glow plug system and starting problems. --> There are many things to check, so buy yourself a workshop...

Hi,

There's new news about my "dollar mine":

ulf wrote:

Damit startgestreßten TDI-Fahrern wie Dir nicht langweilig wird, gibts noch einen neuen Fachartikel über Vorglühanlage und Startprobleme --> es gibt viel zu prüfen, kauf Dir ne Werkstatt . . . {M Hi Ulf, I already have pretty much all the specialized tools needed for VAG vehicles here...

...all that's missing is a garage.


I now had my first long-distance trip, and it started with a jolt at 120 km/h . That was definitely the NBF (No Brake Force) -> that will come out anyway... I don't want to damage the timing belt....but it only occurred sporadically during the trip.
Sometimes, when going uphill or during acceleration, the engine would stop responding. However, it was definitely not an emergency mode triggered by increased turbo pressure. In that case, you have to release the accelerator pedal to "fix" it. I just kept my foot on the gas pedal, and eventually, the engine started pulling again.
Now I don't know if a loose needle in the NBF could cause this problem ? It sounds more like a quantity switch issue.

@Bertil:

You wrote that the MSW can be made more common, right? Can you easily remove the pump head without any diesel fuel leaking onto the coolant hoses? Is there a seal between them? The markings are already there . I also think no metal shavings should get near the MSW, otherwise the electromagnet will be happy.


Regarding the cold start problem:

I was in the mountains, and in the mornings, the engine started well sometimes and poorly other times. At an altitude of 2000 meters, it stood for 6 hours (it was windy) and wouldn't pre-glow, which definitely includes the temperature sensor as a potential culprit (I'm still waiting for the correct transistors for the adapter). Anyway, I could already see those yellow angels in front of my eyes: "organ, organ, organ."

Something pleasant:

I drove 1400 km with the last two tankfuls , resulting in a fuel consumption of 5 liters.

Wishing everyone a happy New Year .

Best regards, Christian.

haehnlein wrote:

Sometimes, when going uphill or during acceleration, the engine would stop pulling. I just kept my foot on the gas pedal, and eventually, the engine would start working again. Now I don't know if a loose needle in the NBF could cause this problem ? It sounds more like a quantity switch issue

?

Hi Christian,

According to an older description (as of November 1998) of the industrial TDI system, in the event of a failure of the No Backfire device (NBF), an emergency program is activated, which includes reducing the fuel injection quantity.

haehnlein wrote:

@Bertil: You wrote that the MSW can be made more common, right? Can you easily remove the pump head without any diesel fuel leaking onto the coolant hoses? Is there a seal between them? The markings are already there . I also think no metal shavings should get near the MSW, otherwise the electromagnet will be happy.

I opened the top cover (and I used a cloth to absorb the diesel). Then, I moved the MSW back and forth several times from one stop to the other. Unfortunately, it didn't last long.
Have you ever tried using diesel fuel as a cleaning agent (undiluted)?

Quote:

Regarding the cold start problem: I was in the mountains, and in the mornings, the engine started well sometimes and poorly other times. At an altitude of 2000 meters, it stood for 6 hours (it was windy) and wouldn't pre-glow, which definitely includes the temperature sensor as a potential culprit (I'm still waiting for the correct transistors for the adapter). Anyway, I could already see those yellow angels in front of my eyes: "organ, organ, organ."

... this could mean that the cold start amount is not correct.

Quote:

Something pleasant: I drove 1400 km with the last two tankfuls , resulting in a fuel consumption of 5 liters. Wishing everyone a happy New Year . Best regards, Christian

.

Excellent consumption.

Happy New Year (don't take it literally!!!!)

ulf wrote:

in einer älteren Beschreibung ( Stand 11/98 ) des Industrie-TDI steht, daß bei Ausfall des NBF ebenfalls ein Notprogramm u.a. mit reduzierter Einspritzmenge läuft.

@Ulf:

That sounds plausible, especially since this problem didn't occur during the test drives with the new nozzles! Let's see if anything like this is stored in the error memory .
Next up, the NBF is coming out!!!

@Bertil:

When the weather gets better, I will definitely run the diesel flush directly through the fuel system and it's best to let it sit overnight.

Assuming the temperature sensor is working correctly:
Can an excessively HIGH initial fuel quantity cause the mixture not to ignite? In any case, the amount of fuel being injected is far too high at idle when the engine is at operating temperature -> resulting in excessive emissions.

Bei Schubabschaltung wird doch die Einspritzmenge über das Mengenstellwerk zu Null gesetzt. Dann ist der zeitliche Versatz zwischen Gasgeben bei kaltem Motor und der ruckartigen Antwort ein Beweis für ein defektes MSW (es sei denn der NBF verursacht dieses Phänomen). Bei warmen Motor tritt dies nicht auf!!! D.h. es gibt einen Temperaturbereich bei dem das MSW klemmt, ähnlich den älteren Magnetschaltern beim Anlasser!!! DaCould the cold start amount be insufficient despite a high fuel pump setting?
It's strange that when the ignition is turned on, the steering wheel lock (MSW) fully unlocks once, and this should actually generate an error in the fault memory .

Best regards, Christian.

"Although it wasn't directed at me, but: The smell isn't caused by too much fuel being injected during idle; in that case, the idle speed would also be higher, as if you were giving it a little gas while idling. My 5-cylinder engine also smells like this, and it's been happening since I bought it (from 109,000 to 227,000 km). I suspect it's due to the fuel injectors, but they are still too expensive to replace. It could also be caused by poor compression."
Starting is not a problem now that the fuel injection timing is correct.
Did you ever measure the timing ratio of the injection adjustment, in the manner of Ulf?
Christian.

Hi,

Thank you for replying!

christians wrote:

Possibly also due to poor compression.

... as far as I remember, Chr. Haehnlein revised the cylinder head, so there shouldn't be any problems with compression (unless the engine block is completely damaged, but that would be obvious even with a worn-out cylinder head).

haehnlein wrote:

When the weather gets better, I will definitely run the diesel flush directly through the pump and it's best to let it sit overnight.

Letting it soak is definitely good, but only if the pump is properly warmed up.
You should try it - it doesn't cost much - the outcome is uncertain.

Deleted upon request.

diesel.gustav wrote:

Hello Bertil, It's interesting and also tiring to read everything that has been written in this thread. Maybe I've missed something. But if I read the texts from the person who started the thread, I don't think they properly checked the preheating system. And based on the description of the symptoms, that's where I would start looking first. But I don't want to go into that right now.

...so far, I haven't looked into the glow plug test, but I assume it's fine. If it's not, that would be very annoying.

Quote:

The spray patterns in your link are very impressive, but they don't necessarily have to be informative. Because the spray pattern depends significantly not only on the condition of the nozzle and the opening pressure, but also on how quickly and intensely the lever of the nozzle testing device is activated. ...

... don't tell anyone - I found them on "Fattys" and linked to them here.

Having recently replaced the injectors in my former 1Z, I can confirm the difference shown in Henzo's pictures. Of course, spray patterns can also be caused by different driving styles (I hope that wasn't the case with those pictures).

Cheers to the New Year!

diesel.gustav wrote:

It is interesting and also tiring to see everything that has been written in this thread. Perhaps I have missed something. But when I read the texts from the author, I don't believe that he properly checked the preheating system. And based on the description of the symptoms, that is where I would start first.

Hi,

I may be "just" a hobbyist mechanic, but I have good experience and I don't understand why everyone is focusing only on the glow plug system .

Here's something to reassure everyone:

Initial current between the positive terminal and each individual glow plug: 19 Amperes.
Initial current between the glow plugs and the corresponding connector when the ignition is turned on: 19 Amperes.
Preheating time at 0 degrees Celsius: 5 seconds!!!

Da muss ein intakter TDI sofort anspringen!!!!! Der 1Z von meinem Vater ist bei abgezogenen Glühkerzenstecker ziemlich gut angsprungen....aber mit etwas Blaurauch und nicht Weißrauch!!!!! Eine defekte Vorglühanlage spielt eine größere Rolle je kleiner die Temperatur ist!!! Das war beim TD so und ist beim TDI auch nicht anders!!! Meiner springt bei minus 10 Grad besser an als bei handwarmen Zylinderkopf nach 4 Stunden Standzeit. DiThe cylinder bores were also in good condition.

--> The compression, the glow plug system, and the fuel injectors are definitely ruled out; otherwise, I wouldn't be writing this here.

Despite everything, I wish everyone a "Happy New Year" .

Best regards, Christian.

christians wrote:

It might not have been directed at me, but: The bad smell doesn't come from too much fuel being injected during idle; if that were the case, the idle speed would also be increased.

It's like giving it a little bit of gas while idling.

Hi Christian,

...The idle speed is sometimes (!) increased (to 1000 rpm), and the reason for this is unclear!
It takes forever to reach this .

christians wrote:

My 5-cylinder engine also smells like fuel, and it has done so for as long as I've owned it (from 109,000 to 227,000 km). I attribute this to the injectors, but they are still too expensive for me to replace. It could also be due to poor compression.

The new nozzles from my father worked on mine, but not on my father's .
The unpleasant odor comes from aromatic hydrocarbon compounds that the oxidation catalyst is supposed to oxidize into H2O + CO2. In addition, the oxidation of sulfur compounds can also cause odors. However, these play a less significant role with low-sulfur fuels! In my old diesel car, after installing an oxidation catalyst, the typical diesel smells disappeared!
A bad smell is definitely caused by a damaged catalytic converter . A few starts with unburned diesel can destroy the catalytic converter . Defective injectors only produce more and larger particles, but their size is nowhere near that of the old TD particles; i.e., a functioning catalytic converter can easily oxidize them.

christians wrote:

Anspringen ist aber kein Problem seit der Einspritzzeitpunkt stimmt.

He's right! / She's right! / That's correct!

christians wrote:

Have you ever measured the timing ratio of the injection adjustment, in the manner of Ulf? Christian

My adapter is not working yet.

Best regards, Christian.

haehnlein wrote:

...Leerlaufdrehzahl ist manchmal (!) erhöht (1000 rpm) mit wrum, wrum!!!!

Hi Christian,

That's absolutely typical for a pump control system that is (way too) aggressively adjusted.

With a bit of luck, you might even be able to fix it using VAGCOM.
I will update the error database entry (DIY troubleshooting guide) accordingly.

Hi Christian,

...The idle speed is sometimes (!) increased (to 1000 rpm), and the reason for this is unclear!
It takes forever to reach it.

Ah, so, Ulf has already written something.

"... The odor problem is definitely due to a damaged catalytic converter. A few starts with unburned diesel fuel can destroy the catalytic converter..."

Interesting. Just think about how that could have happened. It's not as easy with a diesel engine as it is with a gasoline engine, which has its ignition system prone to failure.

Do you mean an adapter that is integrated into the pump cable? I inserted two pins and connected them to the multimeter inside the car using speaker wire.
The VAG-Com method is supposedly less suitable.

christians wrote:

... The odor problem is definitely due to a damaged catalytic converter. A few starts with unburned diesel fuel can destroy the CAT... Interesting. Just think about how it could have happened. It's not as easy with a diesel engine as it is with a gasoline engine, considering its more prone-to-failure ignition system.

Hi Christian,

In my case, the engine has already experienced several cold starts. This leads to unburned fuel coming into contact with the precious metal surface. When the catalytic converter reaches a certain temperature, the fuel ignites suddenly (unless it evaporates beforehand), which destroys the precious metal surface. Furthermore, sulfur compounds are problematic. However, I don't know how much sulfur is contained in modern fuels.
At least a CAT doesn't last forever!

christians wrote:

Are you talking about an adapter that would be installed inside the pump cable? I inserted two pins into it and connected it to the multimeter inside the car using speaker wire. Die Methode über VAG-Com soll ja weniger geeignet sein.

I mean the VAG-COM interface like ULF's -> I'm still waiting for the right transistors .

Best regards, Christian.