Need advice diagnosing starting problem
 

1999 2.3. Hard to start, especially when cold. Holding the pedal to the floor will make it start. Once started it runs great. Fuel pump is 1 yr old. Just tested pressure, 60psi. Before cycling the fuel pump, however, there was no pressure in the fuel system (tested by pressing the Schroeder valve pin on the test port).

After testing the fuel pressure, which of coarse involved cycling the fuel pump 3 more times, it fired right up without pressing the accelerator at all...this on a cold morning.

Thinking next step is fuel injector cleaner to address potential partially clogged, leaky injector, but also wonder if it could be the fuel pressure regulator.

Any input appreciated.

There is no Fuel Pressure Regulator(FPR) on your '99.

There is only a Check Valve(back flow preventer) on the fuel pump assembly in the gas tank.

When you press the gas pedal to the floor and hold it there the computer will shut off the fuel injector but leave spark working.
This is on all fuel injected engine computers, it is called "clear flooded engine mode"

Turn key on
Press gas pedal to the floor and hold it down(TPS is above 4.5volts, RPMs = 0, that's the trigger for this mode)
Crank engine

As soon as you let off the gas pedal computer will restart injectors

I would do this:
cycle key on and off 3 times to build up pressure
Then do the clear flooded engine mode
Turn key on
Press gas pedal to the floor and hold it down
Crank engine

If engine fires, even a little, then you have a leaking injector or leaking Pulse Damper(end of fuel rail, check it's vacuum hose for gas or gas smell)
If engine doesn't fire then leak is in the fuel lines or pump assembly in the tank.

Couple of ways to check which injector is leaking:
Repeat above test BUT...unplug both coils, so no spark, then remove one spark plug from each cylinder to see which on is wet with fuel.

Repeat above test BUT...unplug both spark plug wires on one cylinder at a time, when engine stops firing then last cylinder has the leaking injector.


The in tank assembly can also have a leaking connector, cracked hose.
Once engine starts the fuel pump is on all the time so this usually doesn't effect drivability, just startup, it also won't effect MPG like a leaking injector will.

Rond -Thank you very much for the helpful information. It seems as if there was a partially clogged injector that I have been able to clear.

starting right up on several cold mornings...