I had a Peugeot diesel that had no electronics, it was all mechanical (I used to disconnect the battery and leave it running) and I almost drowned it once. The engine was all wet, and partially submerged and ran fine. It started sputtering when it got water in the intake (bow wave), but the instant it was clear it was fine. It got me past several drowned gas 4x4's. The brakes were gone, the clutch got real pissed, and it took a little while to dry out the interior, but as long as the engine got a reasonably dry gulp of air it could care less.

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5 speed '91 190E 2.6 320,000 mi. (new car, fast, smooth as silk six, couldn't find any more Peugeots)
5 speed '85 Peugeot 505 2.5l Turbo Diesel 266,000 mi. (old car, fast for a diesel, had 2 others)
5 speed '01 Jetta V6 (new wifes car, pretty quick)
5 speed '85 Peugeot 505 2.2l Turbo Gas 197,000 mi. (wifes car, faster, sadly gone just short of 200k )
5 speed '83 Yamaha 750 Maxim 14,000 mi. (fastest)
0 speed 4' x 8' 1800 lb Harbor Freight utility trailer (only as fast as what's pulling it)