Audi A3 accidentally filled with E10 fuel, fuel pump failure

Hello,

Audi A3, 1.6l engine with BGU code. Simos fuel injection system.

Since we were recently in Hungary, my wife mistakenly filled the car with ethanol (E85) instead of gasoline (95). Luckily, she only filled it halfway. She then drove about 100 km, and the car started to malfunction completely. This included extreme jerking and, at times, only idling. And the engine warning light came on.
After that, I towed the vehicle to the nearest gas station and filled the rest of the tank with gasoline (95). After about 5 kilometers of careful driving, the car drove normally again, except for the engine warning light. I then removed them at home, and the error message was something like "fuel mixture" or similar.

Now that I'm home, after driving approximately 800 km, and I've just refueled, the car suddenly started having problems. The vehicle was parked at the supermarket, and then it wouldn't start.
Then it suddenly started working again. I then read the error memory, but it was empty. After investigating, I found that a fuel pump in the tank was intermittently blocking the fuel flow, which was the cause of the problem.

Question: Can ethanol destroy this pump so quickly? So, the pump is making loud noises and seems to be malfunctioning.

Then I went to the Audi website and discovered that only our model is not approved for E10!

I never thought E10 could cause something like this, or what do you think?
I have to say, I would never intentionally put that kind of fuel in my car, because there isn't really a significant price difference anymore, it just happened... I just hope that the fuel injectors and other components haven't been damaged.

Question: Can ethanol destroy this pump in such a short time? So, the pump got clogged, and there were also loud noises)

Yes, unfortunately. The significantly reduced 'lubricating effect' of alcohol is completely underestimated.


Then I went to the Audi website and discovered that only our model is not approved for E10!

This is the case with some models.


I never thought that E10 could cause something like this, or what do you think. I have to say, I would never intentionally put that kind of fuel in my car, because there isn't really a significant price difference anymore; it just happened... I just hope that the fuel injectors and other components haven't been damaged.

It was E85 at your place, not E10.

Is that an FSI?

My Passat is about to reach 200,000 km and has been running on E85 without any modifications and without any problems. I've actually used E85 in all my cars except for the ones with KE-Jetronic, and I've never had any problems.
I'm aware that some FSI engines are said to have problems with ethanol.

"May I ask where one can usually find E85? I've been driving around the Ruhr area, but I haven't seen it available at any gas stations, and I've been looking for it intentionally." I always thought we wouldn't have gotten this far.

matthiasTDI96 wrote:

May I ask where one can usually find E85? Well, I'm just driving around the Ruhr area, but I haven't seen it at any gas stations yet, and that was, intentionally. I always thought we wouldn't be this far along.

Even here in my village, there's an E85 gas station not too far away.

Look, it seems they're here too... the constant search for the cheapest diesel price can make you lose focus. Hmm, or maybe I should go to the ophthalmologist; perhaps they can do something to improve my vision.

I've occasionally read about Ford and Volvo models that are compatible with E85 fuel, but I thought it wouldn't be available in the German market.

There are many vehicles that can also run on ethanol. Even with no modifications or only minor adjustments.
It seems that the VR6 engines from 1993, which have the 'AF' and 'AG' engine control units, are the most compatible.
Most likely due to the wide adaptation range of lambda control/mixture adaptation.
Does it really work perfectly with all Motronic variants, from -15°C to +40°C, when using pure E85?

The Audi ABC and AAH models also handle it well, except for the cold start.
The fuel pressure regulator from the VR6 engine works with ADR, ADY, and 2E models. Using Bosch fuel injectors designed for VR6 engines.
Even the smaller engines, such as the ABS, AAM, and RP, can be made to work with just a few minor adjustments.
I'm not aware of any leaks, or any other issues caused by E85 that have damaged the engines.

On ethanol-tanken.com, you can find a vehicle database where users can register. A directory of gas stations with a radius search function can also be found there.

MFG

Hi,

Okay, I installed a new control unit, and the vehicle is running again. (€230, excluding the fuel sensor!)
I think the ethanol has such a strong cleaning effect that it caused the pump to wear down.
Approximately like brake cleaner. Gasoline, on the other hand, still has a slight lubricating film.

Well, my pump has been circulating in my tank since 1993.
It has been over 200,000 km since it last saw gasoline, and it's still pumping.

Perhaps it was adulterated E85, or it simply had a high water content (ethanol is hygroscopic). Or it could simply be dirt that has dissolved from the bottom of the tank and been drawn into the pump.
Actually, with E85, you mainly experience this strong cleaning effect. Therefore, even after 10,000 km of driving with E85, the fuel filter should be replaced.