1994 Ford Explorer Hard starting after it sits.

[privottfamily]

I've replaced the fuel pump and filter, plugs and coolant temp sensor. It starts after I spray starter fluid in after a few times and cycle the key on to prime the line but is still hard to start. It runs fine and it seems that as long as the engine is warm or (guessing) fuel is still pressurized in the line it starts fine. Any ideas?

[ctwright]

could be a leaking injector, or bad fuel pressure regulator, maybe a leak in the fuel line somewhere, first thing you need to do is look for a leak in fuel line, you want to hook up a pressure gauge, check the pressure, and see if it holds to your vehicles specs, if it doesn't , you then want to test again, and clamp off the line somewhere b/t your gauge and the fuel rail, if it still leaks down then you have a leak somewhere either in the feed line maybe under the car or you could possibly have a bad fuel pump, if doing that test it holds pressure, then do the test again but clamp off the line on the opposite side of the gauge, b/t the gauge and fuel pump. If it doesn't hold pressure during this test then you need to check for a leaky injector(I doubt that is it b/c you already said can start it with starter fluid), if none, and you see no leaks around the fuel rail or line leading up to it I would suspect a faulty pressure regulator.

[shorod]

Checking the fuel pressure is a good start. Also, when is the last time the vehicle had a tune up including spark plugs, plug wires, fuel filter, and air filter? Also, how does it feel during idle (smooth, a bit rough)? Do you have access to a mechanical vacuum gauge?

-Rod

[wrihar]

I had the same problem on my 2000 mustang 3.8. I did the usual things like change the plugs and fuel filter but that did not help. It always cranked for 5 to 8 seconds before starting after it had been sitting a while.
The problem long cranking or hard starting problem turned out to be a leak in the hose going from the fuel pump to the fuel tank flange (in the tank). This is a special flex hose that had a pin hole in it. It allowed the pressure to bleed down after a few minutes. You need to drop the tank and remove the flange on the top of the tank to get access to it. I simply replaced the hose with a high quality fuel injector rubber hose and 2 worm screw clamps.
To verify this is the problem put a fuel pressure gauge on the Schrader valve (tire valve stem type of valve) on the fuel rail. (front left corner of the engine on a 3.8 Liter engine). The pressure should be about 30 psi and 40 when just turn the key on. Newer engines do not have this Schrader valve and you will need to put an adaptor in the line somewhere by opening one of the spring clamp fittings... maybe at the fuel filter or on the engine somewhere so you can measure the pressure. You need a special tool to release the spring clamp fittings available at most auto parts stores for a few bucks. I suggest undoing the output line of the fuel filter and slide your pressure gauge onto the fuel filter outlet and then turn the key on to test the pressure. It should remain at 30 psi after you turn the key off.
If you have a problem your will note the pressure will bleed down after you turn the key off.
If it bleeds down it could only be 3 things. A leaky injector, a bad check valve in the fuel pump or a leak in the hose ... which was my problem. The pressure should be maintained for a long time (in the order of days) after turning the key off.
As a work around to keep from cranking so long and killing your starter and battery you can cycle the key on and off a few times to charge the rail before starting. This will give you time to prepare.... and get the tank empty so you can drop the tank easily.
If you need to replace the fuel pump Napa sells the fuel pump by itself for $152. Most other auto parts do not stock it.
Good Luck.