Hello --- I left my 2015 Lincoln MKS EcoBoost in the garage all winter, so of course when I went to start it, it wouldn't. I found out the the battery was completely shot. I replaced the battery. It's turrning over but won't start. Is there something else that I have to do? Even when we jump it acts like it wants to start but doesn't. Oh it did start with the old battery w/a jump box I left it running for 10min and haven't been able to get it started since. What to do?

With the new battery disconnected, try turning the headlight switch to on and letting it sit for about 15 minutes. This will drain any and all power out of the system. This will also cause the ECU to default to the original map as it was from the factory. Anything it's learned over time of your driving. It may just have corrupted the data causing the nostart issue. Many people who drive things like the Focus ST will do this every oil change to keep the map fresh as the ECU learns over time and adjusts to your driving characteristics. Like, if you rarely ever cause the engine to boost (engage the turbo and build pressure) the ECU runs a lower amount of fuel at certain RPM's to conserve fuel. This also can reduce power over time as it learns. It could be that it doesn't have a working map and isn't able to start. I'd try this first, see what happens. Literally, leave the headlights on for 15 minutes with the battery disconnected. Make sure there's absolutely no power to the system. When you try starting; it may take a few seconds to start; then it may also run poorly as the ECU starts to relearn the engine.