1999 Explorer 5.0 Intermittent Hard Start

[vacuumbed]

Hey everyone,

Usually when the engine is warm, my 5.0 is extremely difficult to start. Once it runs, it runs like a brand new engine. Smooth and powerful. No codes.

Recent tune up; wires and plugs, and air and oil filters along with a new synchronizer all with Motorcraft parts.

I wonder if it could be the synchronizer installed wrong messing up the timing, but the hold down bolt hasn't worked it's way loose or anything.

Any thoughts? Thanks in advance.

 

[974X4BLACKSPORT]

First, narrow down the problem to either fuel delivery, or ignition related problem. When you encounter the "hard start" problem, give a squirt of starting fluid past the throttle body blade and see if it starts, if it does, then it tells you the ignition system is working properly and the problem is possibly a fuel delivery problem. Also, it would be a good idea to have some sort of scanner to check for stored trouble codes and check all the "live" engine data, especially when the "hard to start" problem is happening.

 

[boominXplorer]

Turn the key to on(not start) for 3 seconds then back off. Do it again. Then try to fire it up. If it fires right up you have a fuel pump or check valve issue in the sending unit.

 

[Mbrooks420]

If it always starts good cold, or immediately after shutdown when warm it’s likely you have a failed coolant temperature sensor.