Engine Swap: No Power? Troubleshooting Guide

Hello.

I stumbled upon this page by chance.
"My problem is that after converting the engine from a gasoline engine to a 90hp ALE engine in my Vento, I'm not getting the expected performance; it's much slower than my previous 90hp gasoline engine. The issue seems to be that there's some power at lower RPMs, but not enough in the higher RPM range."
After repeated attempts to read the error codes, the "brake pedal monitoring" error kept appearing, even after replacing the sensor. The error persisted despite the replacement.
The mass airflow sensor and the boost pressure regulator are also new!

Is it possible that the car is in emergency mode due to a fault in the brake pedal monitoring system?
and therefore there is no performance, or does it have no influence, and is there another cause?


Sure, here is the translation of the text from German to English:

"MFG" is an abbreviation for "Mit freundlichen Grüßen," which means "Sincerely" or "Best regards" in English.

Hello, you may not have installed or adjusted the switch correctly.
If it's installed in a restrictive position, there won't be much power output.
The configuration bits can be read using VAG Com / VCDS, but I don't have them readily available.
I don't think it's an emergency mode, but it feels like it.

Accelerate in a large hallway and then, while pressing the accelerator, press the brake pedal with your left foot. The power should then decrease, and that's okay.
No change = faulty switch.

Don't the MSA12/15 TDIs have two switches - a normally closed switch and a normally open switch, one for the brake lights and one for the engine electronics?

That means you had to have someone build it in during the renovation.
If not, it won't work!

Yes, and a faulty switch can lead to a fail-safe mode.

m;

The switch works fine, but when I fully press the gas pedal and lightly press the brake pedal at the same time, it immediately cuts off the power.

The switch is fully engaged, and then the pedal needs to be released and returned to its original position; it should work correctly.
"The black switch controls the brake light, and I added the blue one by tapping into the diesel wiring harness."

And one more thing, it doesn't produce any soot at all! Is that normal, or not?

I really don't feel like it anymore, but somehow, I have to find a way to make it work!

Sure, here is the translation of the text from German to English:

"MFG" is an abbreviation for "Mit freundlichen Grüßen," which means "Sincerely" or "Best regards" in English.

audi-scene wrote:

The switch works when I fully press the gas pedal and the brake pedal (only very lightly) at the same time, it immediately cuts off power! The switch is fully engaged, and then the pedal needs to be released and returned to its original position; it should work correctly.

As long as this continues to happen

Quote:

, after repeatedly reading error codes, the "brake pedal monitoring" error keeps appearing, even after replacing the sensor. The error keeps recurring!

Is that the most likely cause of your power loss?
Currently, there are some tricky pitfalls when it comes to engine conversions: Some data sets require synchronous levels for proper recognition (meaning both MSG monitoring pins must be either low or high, for example, in the 97 G3 AFN), while others require asynchronous levels (one pin high, the other low, for example, in the 01 Ibiza ALH).

-> You might need to change the type of switch on the monitoring device (from normally closed to normally open, or vice versa).
In any case, a diagnostic tool connected to the switch position module should indicate that 2 bits change state when the brake pedal is pressed. If only one bit changes, then a wire is faulty, or the wiring harness is not compatible with the module (e.g., a shift contact shorting to ground when there is an internal pull-down resistor is not logical).

When the brake pedal is pressed, only one value changes within the data blocks (I believe block 2 or 10)!
MSG = engine control unit? We took the control unit and the entire wiring harness from the diesel donor vehicle.


Do the cables go directly from the brake switch to the control unit, or could there be a connection error if they go somewhere else first?

Could someone trace this using a wiring diagram?

Best regards.

Thank you for the previous responses.

audi-scene wrote:

When the brake pedal is pressed, only one value changes in the measurement blocks (I think block 2 or 10)! MSG = motor control unit? The control unit and the complete wiring harness were taken from the diesel donor vehicle.

The brake parameters should be in MWB 6 (I didn't have time to check earlier).

Quote:

Do the cables go directly from the brake switch to the control unit, or could it also be a connection error if they go somewhere else first?

It probably depends on the vehicle type.

I installed a new boost control valve today; it's the one where the lines connect to the turbo.
The other one I had replaced with a mass airflow sensor was the one for exhaust gas regulation!

No significant improvement observed!

Kommt denn der LD hoch und stimmt die LM. Shall / Is
Did you connect the hoses correctly to the MV?
Is there enough vacuum?

I had a performance test done, and the boost pressure was within the lower tolerance range. Based on that, I replaced the mass airflow sensor, the exhaust gas recirculation valve, and today I replaced the boost pressure valve with new ones.

Did you reconnect all the cables to the new part exactly as they were before?

That will never amount to anything!

Should I have another calibration run performed? Can someone provide me with the target values for each parameter?

Sure, here is the translation of the text from German to English:

"MFG" is an abbreviation for "Mit freundlichen Grüßen," which means "Sincerely" or "Best regards" in English.

When you perform a closed-loop tuning process, the target and actual values are output, which can then be easily displayed in a graph. This allows you to observe the loop's response and determine whether it is being properly regulated.

You can also do this yourself, provided you have VCDS.

And what are the target values?

"I couldn't see through it, and it had nothing to do with me?"

The blue curve represents the setpoint, and the red curve represents the actual value.
spec. intake = setpoint
actual intake = actual value

I'm going to have the timing belt checked first, then we'll see!

Perhaps that's the reason.

Maximum speed on a straight road: 160 km/h!

Is that really enough?

The maximum speed depends on the maximum RPM, and that is likely lower now. Before, was it 1000 RPM higher in the lower gears when revving it out?
But even so, it should still be able to reach 160 km/h faster than before with the gasoline engine.