I have a '96 Taurus with 170,000 miles. It takes a long time to start my engine. I checked the fuel pressure and noticed as soon as I shut off the engine, the pressure drops to zero. I checked another 96 Taurus and fuel pressure remains after engine shuts off. I changed the fuel pump, fuel filter, and pressure regulator. Still, fuel system will not hold pressure and takes a lot of cranking to start engine. Is it possible that the fuel injectors are not holding shut when engine shuts off? I don't see or smell fuel but could it be leaking through the nozzle? I can not locate where the check valve would be on the supply side to the fuel rail. I've been told its in the fuel pump, but when I pulled out my old fuel pump I could not notice any check valves. There is a pulse dampener in the fuel line right before the fuel rails. Is it possibly located in here? Any insight greatly appreciated.

it sounds like the injectors are leaking. i'll nose around for a little more info and reply back tomarrow

ok looked at some diagrams and it seems the pressure should be kept in by the regulator and/or the pump. since you've already changed both of them i would check the injectors.

ok looked at some diagrams and it seems the pressure should be kept in by the regulator and/or the pump. since you've already changed both of them i would check the injectors.
Thanks robz84monte. I'll post another message when I change the injectors. I guess the easiest way might be to go to a junkyard and swap out 3 injectors at a time and see if it makes a difference. I'm not sure if there are any easy ways to check specifically for a leaking injector.

Do an on line search for reconditioned fuel injectors before you swap for junk yard ones. At least you'll get a warranty.

Replace Fuel pressure regulator. Test by crimping off return line before switching off ignition. (leaking fuel injectors is the most unlikely problem)

Replace Fuel pressure regulator. Test by crimping off return line before switching off ignition. (leaking fuel injectors is the most unlikely problem)

he already did

I've changed the fuel pump, the fuel filter, the injectors (all 6), and the pressure regulator. The only thing I haven't changed is the pulse dampener. Also, when I changed my fuel pump, I looked at the OEM pump and didn't see anything resembling a check valve anywhere on the assembly. If I still feel motivated, I'll change the pulse dampener but at this point I'm about ready to drive it off of a cliff.

man this is a tough one, have you traced the entire fuel line to try to find any leaks?

Thanks for all of your comments. The one about injectors saved me a lot of money when I changed injectors this weekend. I got them online from injectors4u.com for about 16 bucks a piece and they're warrantied. Unfortunately, I experienced no change with regards to fuel pressure or start time.
Rob, I checked all of my fuel lines and associated hardware especially by the injectors. I detect no fuel odors or leaks. Have you ever heard of the pulse dampener being used as a check valve instead of the fuel pump? I've been doing some research. It appears that in the pulse dampener there is also a check valve function.

to be honest i've never even heard of a pulse dampner (i even did a pretty thurogh search in alldata-an automotive manual data base- and i couldn't find any thing in there about it) what does it look like?
normally i wouldn't recommend just changing parts on a whim but for all that you've already changed (and as much as you've probably spent) i'd say that if isn't too bad then go ahead and change it.