The FW-190 model is fairly old, so it wouldn't surprise me if there were some oddities in its DM. The 4.13 patch finally fixed some serious and long-standing DM problems with the P-40, P-47, Spitfire, etc., so there might be further bug stomping to do on the FW-190's DM.
But, unless you've got evidence to back up your claims you're just whining.
This is my "DM test" which will prove the point one way or another.
In Conf.ini set "Arcade Mode = 1"
Start IL2. Set up a QMB mission with a flight of Ace Wellington III bombers as your enemies. (The quad .30 caliber tail guns spit out a lot of lead and don't shred your plane immediately, so you can see damage effects without getting shot down immediately. The Ace gunners guarantee that you'll get shot up.)
Choose the plane you want to test and attack the bomber flight using stupid tactics. (i.e., flight straight in from the bombers' 6 o'clock level).
Keep track of range as you close. When you get damaged, hit pause and use external views as necessary to see where you're hit and how badly. For anomalous results, take a screenshot.
Keep stats on where you get hit and why you ultimately get shot down. Refly the mission a couple of dozen times to get a decent statistical sample.
If you fly a FW-190 vs. Wellington III QMB mission a couple dozen or so times and you NEVER get an engine fire, then it's probably a DM bug. Otherwise, its probably good DM modeling, with the engine mostly protecting the fuel tank from the front. (Remember, the fuselage fuel tanks in the 190 are beneath the pilot, and the fuel lines to the engine are behind the engine itself. So, you're not likely to get an engine fire unless you happen to hit a fuel line.)