I have a 1990 Dodge W250, 5.9L EFI (Z engine code) with 65,000 miles (no misprint).The issue is when starting from both cold or after a hot soak, the starter takes two attempts to start the engine.
If I crank it for 5 to 10 seconds or longer on the first attempt, the engine will not start. If I crank it for just a second or two, stop, and crank it a second time, the engine starts right up. I don't have to wait, and I don't have to turn the ignition switch to off, or any other such rituals. I crank it, stop cranking, crank again, it starts. Wassup?
There's a lot to cover on this one. You really gotta break out the tools and test accordingly.
It could be a lack of fuel pressure, weak spark, inaccurate Throttle Position or Coolant Temperature Sensor readings, and so on.
I like to start with a scan tool and test for trouble codes and incorrect sensor readings first. The throttle position sensor may be telling the Powertrain Control Module that your right foot has the accelerator half way to the floor; meanwhile it's on the brake pedal. Or a bad coolant temperature sensor could be reading minus 2 degrees on a warm sunny day. Everything copasetic on the scanner forces me to breakout my fuel pressure gauge and spark tester.
The fuel pump may not be putting out enough pressure, the regulator may not hold the pressure correctly or is leaking fuel into the intake manifold, or the powertrain control module may not be turning the pump on at just the right time.
The spark tester simulates a spark plug with about a half-inch gap. A weak spark from a faulty ignition coil can't jump that gap, but it may keep an engine running just fine with the exception of that first start in the morning.
I'm feeling exceptionally educational today, but the condition can be caused by a bunch of other stuff. You can check some of these basics yourself, but try not to buy any parts unless you're absolutely sure on the diagnosis.