Performance restored after factory reset

Hello,

"I'm having a problem with my 1Z engine. After resetting it to factory settings (with no error codes in the memory), it loses power after about a week, which is particularly noticeable by a lack of torque in the lower RPM range. It runs perfectly fine immediately after the reset, but after a few days, the power loss returns! Because the car has stalled twice while driving, I proactively replaced relay 109. The mass airflow sensor, pump, and turbo are less than a year old. How can it be that the electronics are learning the wrong values? I've also used VAG COM to connect to the car after the reset while it's running, and the values were all okay. I'm a bit at a loss as to what it could be." Could it be a faulty sensor, or is it the control unit?

Best regards.
Dodl.

First: There is no "reset" function for the engine control unit. It loses power every time the ignition is switched off.

Secondly: If the vehicle is in a fault mode (reduced power), error codes will also be stored in the fault memory. So, we need to read those and then eliminate them.

I suspect you've been deleting them without noticing, and you mean a "reset" when you say that.

Best regards,
Guste.

Okay, so there are no errors in the memory, which is the problem. I was just browsing the forum and came across a post that might explain my issue. My car also exhibits the phenomenon of stalling while driving, and I also have an alarm system (DWA) that could potentially cause the engine to stall, and as a result, potentially learn incorrect values. Or is that technically not possible? I will definitely check the circuit board of the alarm system for cold solder joints. It has also often happened (sorry, I forgot to mention this), that after turning off the engine while driving, the loss of power gradually became noticeable after a few days, but as I said, I don't know if this can be explained by problems with the alarm system. What do you think about it?

Best regards.
Dodl.

- The DWA cannot switch off the engine.

- What values should the engine learn? It (and its control unit) cannot do that.

Before more wild speculations appear, please provide some information about the actual facts.

- Year of manufacture of the car/engine.
- Part number of the engine control unit (ECU).
- Is it original, or has someone modified it (e.g., through chip tuning)?
- Have you done anything else to improve performance?
- Why were the turbocharger and the fuel injection pump replaced?
- Is this also the correct pump for the engine control unit (ECU)? (-> Part numbers)

m;

Okay, let's get to the facts.

- Year of manufacture (car/engine): 1994 Volkswagen Golf 3 TDI, 90 horsepower, engine code 1Z.
- Part number of the engine control unit (ECU) -> Unknown.
- Is it original or has someone modified it (chip tuning)? -> Original, but chipped by the company "Wimmer Rennsporttechnik" through software modification.
- Have you done anything else to improve performance? -> No.
- Why were the turbocharger and "pump" (likely the fuel injection pump) replaced? -> The turbocharger had a crack at 160,000 kilometers, and the pump was replaced by an unreliable workshop due to a misdiagnosis, and then replaced with a new one (a long story!).
- Is it also the correct pump for the engine control unit (ECU)? (-> Part numbers) I assume so, since I'm having Bosch install and calibrate the pump themselves.

I hope that the data can be used for something. By the way, I spoke with Bosch today, and even the master technician suspects the DWA (door wiring assembly) is the problem. By the way, this issue has already been discussed here in the forum, and many people found the problem to be on the DWA side, so I didn't make it up .

Hello,

Today I encountered an interesting issue. In a Fabia (okay, it's a completely different car), a grounding bolt was loose.

I would like to check the supply voltage at the engine control unit (pin 23: battery positive, pin 24: battery negative on the engine control unit) and, using an LED with a resistor or similar, see if the supply voltage to the engine control unit drops out when the engine stalls, or not.
Then you'll know whether to look for the problem in the wiring between the engine control unit (ECU) and the actuators or the control unit itself, or in its power supply.

Possibly, you could open the engine control unit (ECU) and check if the tuning chips are properly mounted/soldered.

Best regards, Rainer.

I'll definitely give that a try, thanks!

Quote:

Original but chipped

contradiction in terms

To chip a 1Z engine, the engine control unit (ECU) needs to be removed, and the chips need to be desoldered. Here are some options:

* "In this way, you can:"
* "With this, you can:"
* "This allows you to:"
* "You can do the following:"
* "It is possible to:"
- Rip cables.
- Unplug it and don't plug it back in properly.
- Bend pins.
- the new chips were not installed properly (as Rainer mentioned).
- What can be damaged by electrostatic discharge?
Okay, I'm ready. Please provide the German text you want me to translate.

m;

Yes, I believe you. However, I can't imagine that anything happened. Furthermore, this happened more than 5 years ago, and I haven't experienced any problems with the chip during that time.

LG
Dodl.

Just take a look, as the intervention might still be the cause. Soldered joints, especially in vibrating vehicles, can sometimes fail and lead to all sorts of interesting errors. It's really not much work to expand this thing and take a look at it.