Audi A4: Won't Start After Water Ingestion

Hello everyone!

I've already tried searching, but I haven't been able to find what I'm looking for.

Here's a brief summary of what happened:
On Tuesday, it rained heavily in Bonn, causing streets to flood.
A driver of an Audi from the "Audi Forum" online community wanted to drive his A4 through a flooded section of road when a speeding SUV came towards him. The SUV's wave hit the A4, reaching over the roof. The engine stalled, and witnesses reported seeing white smoke coming from the exhaust.
Back home, it turned out that everything was full of water up to the fuel filter. The intake manifold looked dry on the inside. The engine cranked over with the starter, even without removing the glow plugs - so there shouldn't be any water in the cylinders, right? Drying out the engine and the connections didn't help. Diesel is coming out of the fuel injection line.

Yesterday, I was there and read the error codes, and the results were as follows:

VAG-COM Version: Release 704.1
Data version: 20070422

Thursday, May 24, 2007, 6:36:37 PM.

Chassis Type: 8D - Audi A4 B5
Scan: 01 02 03 08 15 16 17 25 35 37 45 55 56 57 67 75 76 77

Mileage: 287,870 km / 178,874 miles.
"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Ein leichter Wind weht durch die Bäume, und die Blätter rascheln leise. Es ist ein wunderschöner Tag, um draußen zu sein."
Address 01: Engine Labels: 059-907-401-AKE.LBL
Part No: 8D0 907 401 D
Component: 22.5l/4VT EDC 0000SG D62
Coding: 02013
Shop #: WSC 06325

4 Faults Found:
01318 - Control Module for Injection Pump (J399)
37-00 - Defective.
01318 - Control Module for Injection Pump (J399)
49-00 - No Communications
00546 - Data wiring fault.
49-00 - No Communications
01268 - Quantity Adjuster (N146)
37-00 - Defective.
Readiness: Not applicable.


At first glance, I would say that water has damaged the electronics of the ESP, although I'm not sure how it could have gotten in there.

Besides these error codes, I'm also wondering if there might be a mechanical defect in the engine, such as "hydraulic lock." The mass airflow sensor is drawing air in and out. There's a slight build-up of pressure in the exhaust if you cover the opening. The starter motor can easily turn the engine over.

I would be very grateful for any suggestions.
MichaelJ

I suspect that either the wiring harness or the ESP (Electronic Stability Program) is faulty. First, I'll measure the compression, then check the wiring harness with a multimeter, and inspect the connectors for the engine control unit and ESP. Only then will I try a new pump. Installing a new pump immediately is risky, because what if the engine itself is also the problem?

The compression test on the engine revealed a very unfavorable result.

The Best cylinder has a pressure of 17.5 bar.
second best, 8.5
the third 6.5

and the rest is no longer measurable.

Could the poor compression readings and the error message regarding the ESP be caused by a slipped timing belt, or will the valves and pistons directly collide with each other?

With the 2.5 model, you'll probably have to use externally mounted timing pulleys, as there's essentially no room for skipping timing belts .

Okay, so, remove both heads, assess the damage, and then, depending on the extent of the damage, decide how to proceed.

It's possible. To be sure, the cylinder head needs to be removed. However, it's also possible that the engine suffered a hydraulic lock. As little as 21 ml of water can completely fill the combustion chamber of a cylinder in your engine (at Top Dead Center).

It's also possible that the piston crowns or piston rings have cracked. It's conceivable that the damage has also spread to the connecting rods and the crankshaft.