Join Date: Dec 2012
Location: Phoenix, AZ
Bronco Info: '88 Bronco XLT, 5.0L, AOD, 33's
I've had this same issue with my BKO since I got it. Exact same. New IAC, new fuel pressure regulator, new pumps (rail and tank), new gas cap, new injectors, TB inspected, new fuel reservoir (thought the check valves might be sticking), new fuel lines, wiring inspected. That's just on the fuel side.
I thought the ignition might be to blame instead, so, I tested and replaced many old parts that were "questionable." Motorcraft coil, plugs, wires, and a brand new (non-rebuilt) dizzy.
All replaced items are Motorcraft, except, for the in-tank pump which is a Delphi and the dizzy which is Richporter. Absolutely, nothing has changed about the "hard-start", which is just as the OP describes. In the morning, I have to prime twice to get it to fire in a short period. Otherwise it'll crank and crank.
Everything tests fine electrically, and in mechanical operation. I just don't know what I'm missing, so, I gave up because it has never failed to start, it just takes excessive cranking after it sits for more than 5 hours/over-night. If I'm bleeding fuel pressure, which is what I suspect, I have no idea from where. In the summer, it's, also, worse. My theory is that the fuel pressure in the lines/fittings/tank become greater with the ambient temperature (thermal expansion) and force the leak-down to become more rapid.
I mean, why would I have to prime twice in the morning? Are my lines, just, bleeding down, somehow? That's got to be it, right?