Hohe Dieseltemp. AJM+Folgen | Posts 16+

Someone seems to have copied something from tuneline.at... or am I misinformed? They, in turn, copy from MTZ.

Otherwise, I would say that the AJM engine is naturally good based on the described components, but I would never describe the first PD (Pumpe-Düse) version as a "very good" engine. It had other weaknesses; the first attempt by VAG (Volkswagen Group) was quite a feat. So, try searching for "AJM."

Oh, and one more thing,

While in the summer, with a completely empty tank and extreme temperatures, it might be possible to cause damage. But that's just speculation on my part...

You won't believe this, but a half-full tank is much more critical than a nearly empty one. Also, the tank itself, with its exposed surface, has a cooling effect. The ratio of the fuel volume to be cooled to the tank's surface area is less favorable when the tank is half-full compared to when it's almost empty.

Oh, and one more thing,

While in the summer, with a completely empty tank and extreme temperatures, it might be possible to cause damage. But that's just speculation on my part...

You won't believe this, but a half-full tank is much more critical than a nearly empty one. Also, the tank itself, with its bottom surface, has a cooling effect. The ratio of the fuel volume to be cooled to the tank surface area is less favorable when the tank is half-full than when it is almost empty.

Hello,
What is this claim supposed to mean?
When the tank is about half full, there are initially almost 30 liters of cold fuel that need to be warmed up.
They won't be ready until the tank is 'empty'!
Best regards,
Günther.

"Isn't there some kind of standard or regulation specifying how long a fuel tank in a burning car must remain intact before it's destroyed? If we could find that, I don't think we'd need to discuss the diesel return issue..."

Best regards,
Stefan.

Hello, it's me again.

The issue with the starting problems (rough idling before starting) has been fixed. Just wanted to post that.
Battery is 5 years old, and then there's the winter -> for professionals, it's clearly the battery. I've had an 'Accu-Refresher' connected for 2 days now. What can I say, it's not my imagination; the starting is like a gasoline engine. I also think that you might be able to extend the battery's lifespan by another 2 years with this. So, just a comment on the tips that suggest an immediate battery replacement. You can try this alternative as well. Give alternatives a chance. I've also had this connected in my father's ALH for two months, same battery age, same effect.
The part costs 14€ and you can find it at EL* electronic. This is not an advertisement, just my experience.

Hello,
Could someone explain to me why the tank is now supposed to heat up more? Only a sensor signal was manipulated; the actual return temperature is the same as before.
Regards,
Perwollf.

perwollf wrote:

Could someone explain to me why the tank should now heat up more strongly?

Only a sensor signal was faked; the actual return temperature is the same as before.
Not quite:

The higher the engine load, the higher the actual return temperature .

When operating within the range of the additional tuning performance, the return flow temperature is actually higher than with the standard performance, and this is also the case after the return cooler.

So, warmer fuel is being returned to the tank.

Ah, so, because of the increased performance, it results in higher CPU temperatures.
That would affect any kind of tuning. Huh, that would be my least concern after tuning...

Bei mir (A4 mit PD, AVB) ist in der Ruecklaufsterecke ein Kraftstoffkuehler eingebaut. Kenne noch der A2 1,4TDI besser. He has it too.

Thank you, Ulf!

AFAIK, every PD TDI engine has a fuel cooler.

perwollf wrote:

Oh, so, because of the increased performance, it results in higher CPU temperatures.

Not only are the engine temperatures higher, but the diesel temperatures are significantly higher!
Under typical PD (positive displacement) pressures, diesel also becomes compressible and heats up in a similar way to air.

During injection, it imparts heat to the PDEs, and the amount of heat is proportional to the injection volume and, consequently, the injection duration.

This heat is dissipated from the PDEs by the constant fuel circulation (outside the injection window), so that the unburned diesel actually serves as a cooling medium.

Disclaimer:
This is my theory about the real-world phenomenon of return temperature dependence on performance.
"If you know any other facts, please post them!"

@Ulf: That sounds reasonable to me. Thanks for the explanation!