I'm trying to get the motor to fire on my parts car. The motor is the main thing I want on it, I plan to swap it into my truck later. Anyway the car has sat for nearly a decade. "Ran when parked" of course. I disconnected the fuel lines from the tank and have the fuel circulating from a bottle connected right at the pump. Diesel leaks out when I prime the fuel pump, which may be a problem, who knows. As I turn the engine over, diesel does seem to go through the system (or at least it comes out of the return line above the primary fuel filter). There's no air filter in it so I'm pretty sure that it's getting air to the cylinders. Typically with cars I do the "fuel, air, spark" check but I honestly don't know what the equivalent of spark is for diesels. My 190 sat for a long time before I bought it but it fired up as soon as I tried to crank it. Since this one won't fire I'm at a bit of a loss. Any troubleshooting tips?

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2010 Mercedes E350 4Matic - 77k miles
1986.5 Nissan D21 V6 4x4 - 276k miles
1987 Mercedes 190D 2.5 Turbo - 3??k miles
1983 Mercedes 300SD turbo parts car
2017 Honda CBR500R - 15k miles
2016 Suzuki GSX S1000 - 9k miles