long starting, fuel pressure wont hold when engine turns off.

[lav mechanic]

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.

[robz84monte]

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

[robz84monte]

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.

[lav mechanic]

Originally Posted by robz84monte

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.

[86TATpi]

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

[jc glass]

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

[robz84monte]

Originally Posted by jc glass

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

[lav mechanic]

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.

[robz84monte]

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

[lav mechanic]

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.

[robz84monte]

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.