Car won't start after water damage

Hello,
Yesterday, I accidentally submerged my car in a pond. I managed to get it out, and it even ran afterwards, but now the engine won't start. It just cranks.
Perhaps someone here has experience with this and can tell me what to do to get it working again. The car is an Audi B4 1.9 TDI.


Best regards,

Thomas.

Hm... sorry, but which party were you at yesterday?

It's difficult to make a remote diagnosis. If water was sucked in, it could have caused damage to the injectors or pistons. Rust is also a concern, which can significantly reduce compression.
It's possible that water could have entered the tank through the fuel vent... unfortunately, there are many possibilities.
How deep is the car in the water, and for how long has it been there?

The car was submerged up to just below the seat cushion. The engine is running again, but poorly. I checked earlier and unfortunately, there's air in the diesel line. I'll try to bleed it.

I would just let it dry completely and then try again.

Best regards, WarLord.

I tried to get it running today, but there are constantly air bubbles in the fuel line. It starts after a while of cranking, but you can feel it stuttering when the air bubbles appear. It seems to be taking the fuel normally and is just producing a little more black smoke than usual. However, it shuts off again after about three minutes. Could it be that there's too much air in the diesel pre-filter? I couldn't see anything wrong with the fuel lines coming from the tank.
The light in the cockpit for the engine electronics is constantly on, and the glow plug indicator is blinking. There are also some strange noises coming from the engine compartment, near the vacuum relay next to the turbocharger. I tried to read the error codes with VAG-COM, but unfortunately it didn't work. It wouldn't connect, and I could only access the ABS control unit, even though I increased the baud rate to 240.Can someone help me?

Best regards,

Thomas.

Lord, let it rain brains... but quickly!

Your car is essentially a total loss; it's no surprise that it doesn't run anymore, and frankly, it's amazing that it still does anything at all.

Now, think very carefully about which medium you submerged your car into... well? Water... and not air.

Okay, so here's what you need to do: First, disconnect *all* (!!!) the connectors and dry them out thoroughly (ideally with compressed air or a hairdryer). You should also replace the diesel filter immediately because it will be full of water, not air (where would the air come from?). If you continue running the engine like this, your ESP system is more likely to fail due to insufficient lubrication from the diesel. Also, dry out the glow plugs and their connectors as well.
The MSG will certainly also be flooded because you probably submerged it with some force, and the water wave likely splashed into the engine compartment. The speedometer and the central electronics underneath need to be dried as well. So, disconnect all the connectors... well, you know.

Turn off the engine, disconnect the battery, and make sure everything is completely dry first. If you try to force it like that, you'll end up causing more damage than good.

Make sure that the entire fuel injection system is completely filled with diesel. Disconnect the fuel line leading to the pump and connect it to a container of diesel. Run the pump for at least 5 liters until it circulates diesel only.

If there's water in it, that part will quickly turn into worthless scrap metal.

CU Gremlin.

Hello Thom,

Even if you manage to get the engine running again, the car is a total loss. All bearing points of the auxiliary components will corrode, and switches, contacts, hinges, etc., will corrode over time. It has been submerged in water for too long, which the surface coating was not designed to withstand. This will become an endless project of tinkering and repairs.

Best regards,
Christian.

Habe heute die komplette inneneinrichtung rausgemacht und das auto getrocknet. Dann ich ich den Dieselfilter rausgemacht, es war kein wassser drin diesel ist ja leichter wie wasser. Getrieböl ablegelassen war auch kein wasser drin. Tank ausgepumpt und saubergemacht,habe ich aber auch kein Wasser gesehen. Morgen werde ich noch das Öl ablassen, aber ich glaub da ist auch nix drin. Das was mich mehr beunruhig das das Steuergerät ein wenig Wasser abbekommen hat. Hab schon öfters Handys mit den gleichen Syptomen gehabt also ins wasser gefallen und die bringt man des öfteren mit reinigen mit proylalkohol wieder hin ich werde es mal versuchen. Man sieht es ja an der platine wo Wasser war. KCan you actually take an engine control unit (ECU) from another B4 (1Z) and use it?trying to figure out why there are different data states?
Can someone explain to me how to properly ventilate a car? I've read about it in books and here on the forum, but the instructions were all different. The car wasn't submerged for very long, only about half an hour, and the water level was just above the door sill of the driver's side door. Is it possible to have the engine control unit (ECU) tested outside of the vehicle?

Okay, I checked everything and started the engine, and look – it's running again, without any error messages from the control unit. Yesterday, I cleaned the oxidized solder joints with isopropyl alcohol, which is what I did with the area connected to the control unit.

Thank you very much for your help!

Thomas.

Okay, but now we want a picture of the Audi while it was in the water!

Unfortunately, I didn't have one either. Some people wanted to take a picture, but they didn't have a camera with them. We were all standing in the water.