Kaltstartproplem beim 1Z nicht gelöst *heul* | Posts 125+

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.

Deleted upon request.

diesel.gustav wrote:

mir ist kein Dieselkat bekannt, der durch "Orgeln" kaputt gegangen wäre.

Hi,

How do you plan to measure that? Catalytic converters don't significantly reduce soot or NOx emissions! Oxidation catalytic converters in diesel engines are more about politics than environmental protection!!

diesel.gustav wrote:

That's only logical: If diesel fuel is injected during startup and doesn't ignite, it remains in the combustion chamber of the TDI engine, or it enters the engine oil through the piston rings. A small amount probably also ends up in the exhaust system.

"Not clear!! The white smoke coming from my vehicle is made up of unburned diesel particles, not water!!!! But maybe that's not enough?!"

diesel.gustav wrote:

Before the catalytic converter, there is the upstream converter with its rough cast surface and the turbine, which also absorbs some emissions. Small amounts of residual substances in the catalytic converter are only converted when the catalytic converter's light-off temperature is reached. However, this temperature is above the levels of volatile diesel components that have already evaporated from the monolith (with odor development) by then. Only after reaching the light-off temperature can an increased temperature develop as a result of the conversion process, which is dangerous for gasoline engines but not for diesel engines.

I'm not entirely sure whether the diesel residue in the catalytic converter evaporates before the engine reaches its starting temperature .

diesel.gustav wrote:

The diesel exhaust is also relatively cold near the engine, and an additional temperature increase from the conversion of unburned diesel in the catalytic converter would not damage the catalytic converter at all, but would temporarily even increase its conversion rate. The currently low sulfur content in standard diesel is also not a problem.

"That's not entirely correct: While gasoline engines produce more heat (leading to lower efficiency), the combustion temperature of diesel is higher than that of gasoline (which leads to NOx formation!!!). This means that a small amount of unburned diesel, combined with a hot catalytic converter, can damage it. Furthermore, there is abrasion of the precious metals. There are even studies investigating the potential health risks associated with these metal aerosols."
Best regards, Christian.

I also don't believe that unburned diesel fuel will remain neatly contained in the sump. After all, the droplet size is very small.
When my car used to have trouble starting, there was also immediate white smoke.
The exhaust gas temperature is actually quite low. The compression ratio is higher than in a gasoline engine, which means that despite the higher combustion temperature, the exhaust gases leave the cylinders relatively cool. Also, it's important to remember the high excess of air used in the process.
Unfortunately, I don't know the temperature at which diesel residue ignites in the catalytic converter. However, it might be lower than the temperature at which the catalytic converter reaches its full performance.
I also thought that the diesel would have evaporated by then.
The fact is that some TDIs have a bad smell, and if a fuel injector replacement doesn't fix it, or if everything else seems to be working fine, there are few other explanations.

I have something on the topic of:

http://www.emitec.com/pdf/haus-d-technik-1999-de.pdf

diesel.gustav wrote:

Hello everyone, I am not aware of any diesel catalytic converters that have failed due to "organs."

... me either (that's rare even with gasoline engines). The catalytic converter is quite durable.
"In my rally car, the catalytic converter is subjected to extreme stress (misfires due to the mechanical rev limiter, impacts to the casing from bumps, etc.), but it's still functioning! How could a diesel engine, with its already lower combustion temperature, damage the catalytic converter? I don't believe it!" (see description Diesel.Gustav)

Quote:

... Note to Bertil regarding the spray pattern: I am aware that it has been shown in fatty fuels and FMSO. However, this does not necessarily mean that it is relevant. It could also be a hidden "motivation" for potential buyers. And these are not gasoline engine injector nozzles. I have already described my experience with nozzle testing, so I will not comment further on that.

... I haven't seen anything like that before . Criticism is welcome!!

Bertil wrote:

... me either (that's rare even with gasoline engines). The catalytic converter is quite durable. In meinem Rallyeauto wird der Kat exrem misshandelt (Fehlzündungen durch mech. Drehzahlbegrenzer, Schläge an das Gehäuse durch Aufsetzer usw.) aber der ist immer noch in Ordnung!! Da soll ein Diesel mit seiner eh schon niedrigeren Verbrennungstemp. den Kat zerstören?? Glaub ich nicht!!

Hi Bertil,

The cat [device] will not naturally break down mechanically, but rather the very thin (!) layer of precious metal deposited on the ceramic body (but perhaps not )!!!
The combustion temperature of diesel is higher than that of gasoline (leading to NOx formation). The heat flow through the catalytic converter is lower in particularly efficient TDI engines.

Best regards, Christian.

haehnlein wrote:

Hi Bertil, The cat [device] will not naturally break down mechanically, but rather the very thin (!) layer of precious metal deposited on the ceramic body (but perhaps not )!!! The combustion temperature of diesel is higher than that of gasoline (leading to NOx formation). The heat flow through the catalytic converter is lower in particularly efficient TDI engines. Best regards, Christian

.

"Sorry, I misspoke. I meant the exhaust gas temperature, because that is crucial for the catalytic converter (as you also mentioned)."
The catalytic converter can only affect the engine's performance if it is mechanically defective (clogged).
Whether the KAT has an effect or not is actually irrelevant to you, because even the authorities cannot determine whether the KAT has an effect or not. What's important is that it allows passage!
By the way, if the vapor-deposited layer detaches from the substrate (usually ceramic), the coating will fail because the extremely fine pores become blocked. This results in a mechanical defect.

Deleted upon request.

Hi there,

My experiences with diesel catalytic converters are as follows:

My former Golf 3 TDI with 90 horsepower: After approximately 160,000 km, and having mostly run on biodiesel, the catalytic converter still works. This is easily noticeable because the characteristic smell of biodiesel in the exhaust disappears as soon as the catalytic converter gets hot.

My wife's Volkswagen Golf 3 TDI with 90 horsepower: After approximately 130,000 km, mostly long distances driven almost exclusively on diesel, the catalytic converter no longer functions properly. This was evident because the car emitted a smell typical of biodiesel when using it, even with a hot catalytic converter. This remained true even after driving for an extended period on the highway using biodiesel.

I suspect that the main reasons for this are due to the sulfation of the catalytic converter by the sulfur content in the diesel fuel, which is likely not as reversible as previously thought.

Regards,

Eike.

Hi Eike,

I think it's quite adventurous to try and identify a substance based solely on its smell!
You should also use new nozzles for this!
After replacing the injectors on my 1Z engine, it suddenly smelled like new again, and the "french fry" smell was significantly reduced when using biodiesel. Could the catalytic converter have somehow repaired itself?
You can see it here, but you can't determine the cause-and-effect relationship from this.

Okay, let's get back to the main topic:

I was just messing around with VAG-COM a bit.

Error codes:
- 00550 (Could the control unit be faulty? Relay 109?)
- 65535 (Pump? Possibly a typo or abbreviation)

I reduced the fuel injection amount, and lo and behold, the "wrum wrum" noise disappeared. However, I could only reduce it from 128 to 108 in channel 1!! I couldn't go any lower -> but the engine wasn't fully warm yet.

I have checked the start of the subsidy and my static setting is exactly on the target line, according to a technical article .
Is the value in block 004, field 3 ("actual start") also the start of the feed??? Why doesn't it show "v. OT" or "n. OT" after the degree symbol??? My setpoint is 17.4° (field 2), and the actual value is 3.5° ?

I haven't been able to properly test the temperature sensor yet -> the engine is too hot, but after 4 hours of standstill, it's still 37 degrees (waiting until tomorrow).

I'm sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL.

This post made me a little uneasy .

Best regards, Christian.

christians wrote:

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

Hi everyone,

I haven't quite understood this yet . Does the value in field 4 of section 004 have to be within a "buffer" range of 3-70 during driving, across all RPM ranges (as VAG-COM indicates) ? In my case, the value is 75% at idle???? Does this indirectly determine the fuel injection start? Don't rush into anything .

Best regards, Christian.

haehnlein wrote:

- 00550 (Could the control unit be faulty? Relay 109?) - 65535 (Pump? Possibly a typo or abbreviation)

Hi Christian,

00550 = Start of injection, pressure difference.
The cause could be a defect in the injection control system or a pump that is severely misconfigured.

65535 = Engine computer failure
Delete it and see if it reappears...

Quote:

I reduced the fuel injection amount, and lo and behold, the "wrum wrum" noise disappeared. However, I could only reduce it from 128 to 108 in channel 1!! I couldn't go any lower

.

A limited adjustment range is normal.
It would be interesting to see the displayed fuel injection amount in group 1 before and after adaptation, with the engine at operating temperature.

Quote:

Is the value in Block 004, Field 3 ("actual start") also the beginning of the pumping process??? Why doesn't it say "v. OT" or "n. OT" after the degree symbol??? My setpoint is 17.4° (Field 2), and the actual value is 3.5° ??

Actual Start is the start of injection = approximately the start of fuel delivery.
After overtime (OT), the time I work is indicated by a negative number for me.

Are the 17 and 3.5° values measured with the engine running? Is it at idle or under full throttle acceleration?
(The data is meaningless anyway when the engine is not running!)