I'm still trying to get my sisters 88 740 turbo to 100%. I've replaced a few hoses and vacuum lines and cleaned everything up, but it still has a problem with starting. The first couple times you start it, it stalls, then finally it will stay running. It also has a rough idle, especially after braking. As soon as you let off the accelerator and put it in neutral or hit the clutch it drops down to about 500 RPMS for a second before coming back up to 800-1000. Also has 2 coolant hoses blow out, the lower radiator hose that also goes to turbo, and the heater control valve/hose. Engine seems to be running hot, but the temperature gauge is normal. I've already replaced the fuel filter, it was black inside. Main pump turns fine, not sure about in take pump, could that be the culprit on the hard starts?

 

Let me start by saying that a lot of what you describe would make me check the head gasket before I went much further. 20+ years is a long time for a head gasket...especially a turbo. Blown rad hoses is often a sign of the combustion gases getting into the coolant and over pressurizing the cooling system. A shop can check the coolant for the presence of combustion gases. When that is dealt with, and assuming the gasket tests ok, then I would replace ALL the vac hoses...not some. Turbos not only run vavuum in those hoses, they also run positive pressure under boost. They can and will leak...and a good chance you won't find 'em visually. When I say all the vac hoses, I also include the climate control hoses, iac hoses and brake booster hoses..ALL of 'em. But honestly...I'd check the head gasket before I spent a penny anywhere else.