AFN: 5100 RPM at 37% Load - Why?

Hello.

I installed an AFN engine into a VW T3 van and also fitted a throttle body from a Golf 4.
"Everything is actually working great, except that the engine reaches a speed of 5100 rpm at 37% throttle opening, without any load. Essentially, I only have a little more than a third of the entire pedal travel available to control the range between idle and full throttle."
The engine control unit (ECU) is from an AFN engine, originally found in the Volkswagen Golf 3.

I hope you can help me with this.

Best regards, harix.

My scooter's engine is already revving into the red zone at 10% throttle, even without any load.

think about it again...

CU Gremlin.

OK.
That might be true for your motorcycle, but even when riding, I only use the first 40% of the throttle pedal range. Because with the remaining 60%, the engine power doesn't change at all. I think something might be wrong there; the engine is under load and can't simply rev up.
Furthermore, I can precisely control the engine speed from idle to 5100 rpm within the first 37% of the pedal travel, without the engine being under load.

I hope this makes the problem a little clearer.

PS: The engine delivers its full power when the accelerator pedal is pressed 37%.

Best regards, harix.

Hi,

How do you know that it's exactly 37%?
Is that the percentage value from the pedal position sensor, taken from the measurement data blocks?
If that's the case, then there is a lack of power, meaning that with more gas, you should get more output.
Error memory?

Best regards, Rainer.

Hi.

The error memory is empty, and I read the 37% parking brake engagement value from the control unit.
When I drive the car, it performs as expected for a car with an AFN engine, meaning the engine delivers its full power (110 hp). The only problem is that the engine control unit seems to be delivering the amount of fuel injection that it normally would at 100% throttle opening (PWG), but it's doing so at only 37% throttle opening.

Could it possibly be a software issue in the control unit, or are any of the 6 cables connected to the throttle position sensor incorrectly?

Best regards, harix.

um...

Okay, here's a dumb question:

Why did you connect a G4 gas potentiometer to an AFN control unit?

Or better yet, why are you surprised by strange behavior?

As far as I know, the AFN (Automatic Frequency Navigation) was never included in the G4 model, so it would never have had that potentiometer. How do you know that it's compatible?

m;

harix84 wrote:

...The only problem is that the engine control unit seems to be providing the engine with the amount of fuel injection it would normally receive at 100% throttle position (PWG), even when the PWG is only at 37%. ...

Hi, apparent or certain? How many mg per injection, and at what speed?

Sure, I will translate the text from German to English and correct it if necessary. Please provide the text you would like me to translate.
"But if the ECU displays 37% pedal travel (PWG) at approximately 40% pedal travel, then the problem, if there is one, isn't with the PWG itself. It's clear that the ECU can monitor the entire pedal travel range (0-100%) through the measurement block."
So, the error must be somewhere else. There are bound to be plenty of potential sources of error in a conversion like this. So, the first question is: is everything connected correctly, according to the correct wiring diagram?
Is everything that's supposed to be connected for the engine management system actually connected? There are always people who think you can leave out all sorts of things.

By the way, more people have already done that with the accelerator pedal from the 4-series, and it works.

Greetings.
dieter
T3 Syncro 16 AFN (also modified by the owner).

Quote:

T3 syncro 16 AFN (also also modified by myself)

DREAM CAR!!! (ideally as a DOKA)

What makes the G4 Gaspoti better than the G3?

If I were to install a G3 engine, would I also install a G3 gas pedal as the first step?

*curious*

m;

Quote:

What is better about the G4 Gaspoti compared to the G3? If I were to install a G3 engine, would I also install a G3 gas pedal as the first step?!

I did the same thing. I pulled back and shortened the throttle cable and mounted the potentiometer under the driver's seat. It's always nice and warm and dry there.
The G4 part fits into the bus and replaces the original pedal, which some people find easier or more aesthetically pleasing.
Here's more information:
http://www.suhr-online.de/tdi.php?site=6

Greetings.
dieter

Company thanks.

* search now (ex JX) T3 16" Synchro Doka without motor *

Hi,

Dieter has already answered the question about the Golf 4 accelerator pedal.

I haven't yet made any measurements regarding mg/stroke, but I will do so over the weekend and report back. The performance figures for the engine described here are, so to speak, based on a feeling. I can't imagine that the engine is still lacking 60% of its power, because if it were, it would tear the car or the pickup truck apart. The pickup truck manages just under 160 km/h, and an AFN engine with only 40% power certainly wouldn't be able to achieve that with this "barn door" (referring to the engine).

The values that the control unit receives from the accelerator pedal sensor approximately match the actual pedal travel, so in my opinion, it can be ruled out that the accelerator pedal sensor is sending incorrect values. The only remaining possible sources of error are the wiring, which I installed as described in http://www.suhr-online.de, or the control unit itself.

What do you think about that?

Best regards, harix.

Um, I think there might be a flaw in your reasoning here.

40% accelerator pedal does __not__ mean 40% power.

Explainable with just two examples:

1. Idle speed = 0% accelerator pedal - if this also meant 0% power (i.e., 0% fuel injection), the car would stall immediately.

2. Starting without gas - In this case, too, it would stop after about 2 cm, because the car would hardly be able to run on the idle fuel supply. In reality, the EDC system compensates (as Ulf suspects, up to full throttle = full fuel delivery, in the case of the AFN engine).

BTW: Why are you setting the AFN (Air Flow Needle) to 5100 RPM when the engine is idling? That must be painful!

And another point: The boost pressure without load is very low, which would be incorrect, because with load, it is much higher at the same engine speed!!!

m;

Hi,

The boost pressure is 1.1 bar (analog display) under full load.

The performance isn't actually the problem, because it's perfectly adequate.

The real problem is that if I press the accelerator pedal about a third of the way, the car reaches its maximum speed in 4th gear. The rest of the pedal travel is essentially useless, while in the other gears, I also reach the maximum speed of that gear with the same amount of pedal travel.

Best regards, harix.

Hmm, I got a little too hung up on your first post, because you wrote "without load" there.

Can you log the pedal and injection values?

We probably won't get any further by just making guesses (without using numbers).

m;

I've noticed that too. I'll do a test run with the laptop this weekend and log the data, so you can get a better understanding of the problem.

Best regards, harix.