PD Tuning: Cheap Options & How They Work

Hello!!

Bei Ebay versteigert einer regelmäßig Eigenbau-Boxen. FFor VE and PD.
I understand how it works with VE, it's just about getting more power. But for PD, it's supposed to only add 10-13 horsepower.

Does anyone know about this?

You'd think that with a 10% increase in power, not much could go wrong compared to a modified engine that injects 25% more fuel. But that homemade engine probably doesn't have any kind of overload protection.

Article number: 1923878362.

Hi,

After careful consideration and multiple reviews of the documentation for various PD engines, I would like to offer my opinion.
The seller states "...no boost pressure increase...", so it has nothing to do with the pressure sensor. The remaining analog signals are:
LMM (G70)
Coolant temperature sensor (G62).
Intake air temperature sensor (G72).
Fuel temperature sensor (G81).

We discussed tuning via the mass airflow sensor (MAF sensor) a long time ago and concluded that it wasn't a viable option.
Adjusting the engine through fuel temperature is certainly possible, but it likely won't yield significant results.
I'm not entirely sure what effect the intake air temperature might have, but I believe adjusting the coolant temperature could make a significant difference.
According to Bosch's documentation, the coolant temperature is used as the primary parameter for calculating the amount of fuel injected. I have no idea how much of a difference this makes or what risks it might involve.
By the way, the PD engines have a two-part coolant sensor. Contacts 3 and 4 are connected to the EDC (Electronic Diesel Control), and contacts 1 and 2 are for the display instrument.

Hello Bertil,

Could it be that the coolant temperature is primarily used to prevent a cold engine from being overloaded? It has already been observed that cold PDs (presumably referring to a specific type of engine or component) don't perform optimally.

Best regards,
Eike

eike wrote:

Could it be that the coolant temperature is primarily used to prevent a cold engine from being overloaded? It has been observed that cold PDs (presumably referring to a specific type of engine or component) don't perform optimally.

... That's probably the case too. I think it might also be due to something else, because my first Z3 also felt weak and lacked power right after a cold start (it couldn't even pull the window lifters).
According to the description from VW: If the sensor fails, a replacement is expected, and this will result in significant performance losses.