I have a1999 ranger 3.0. When it sits awhile it is nearly impossible to start. Backfires just won’t crank. When eventually I do get it started it runs fine and starts fine until I let it sit a couple of days. ????

 

Welcome to the forum

The fuel pump in Rangers only runs for 2 SECONDS when you turn on the key, and then will NOT run again until engine starts up

So try this, turn key on, count to 3, turn key off
Repeat this 3 times and THEN try to start

Fuel system should hold 20+ PSI pressure for years, but sometimes the fuel pump's check valve or Regulator leaks a bit, so fuel drains back into the tank, and pressure at the engine drops to 0 PSI
Not a big deal, if you know about it.

Each time you turn on the key that 2 second run time adds 10psi, so 3 times should be 30psi and enough to start up, with engine running and fuel pump on full time pressure is/should be 55psi


If you are wonder WHY doesn't fuel pump come on with the key and STAY ON????
Its a safety thing
Computer monitors engine RPMs, of course, if RPMs are below 400 then it cuts fuel pump power, starter motor only gets engine to 200rpm

If there were an accident and a fuel line broke, the engine would run out of gas and stall, 0rpms, so fuel pump would shut off, and not continue to pump out gasoline from the broken fuel line, which would be a BAD THING in most accidents

 

Could it be check valve in pump or pressure regulator

 

But honestly it seems more like flooding then lack of fuel

 

Both are part of the fuel pump assembly in the gas tank, so you wouldn't try to ID which one was the problem, you just replace the assembly

It would be hard to flood a cold engine that has been sitting a few days
Cold engines like extra fuel, that's why engine are Choked when cold, "choke" means to restrict air but add more fuel
And gasoline evaporates pretty fast, so after a day intake should be dry as a bone if any gas leaked in

You can pull off the Air tube from the intake and open the throttle then smell the intake BEFORE trying to start, it shouldn't smell like gasoline of course


If you think its flooding then do this
Turn key on
Press gas pedal down to the floor and HOLD IT DOWN all the way<< this tells computer to turn OFF fuel injectors, but spark is still on
Crank engine over

It should not fire, or start, no fuel is present

This is called "Clear Flooded engine mode" all fuel injection computer have this, not a Ford thing
I do this every morning on my high mile 4.0l engine, I want to get oil pump through the engine before it starts up
I hold gas pedal down and crank for 5 seconds then release gas pedal and it starts up

 

Is it easier to drop the tank or take the bed off

 

Take off the bed, or tilt it up
Unless you have a shop with a lift and transmission jack, its too hard to lift the tank back in without pinching hoses or pulling out wiring harness

But find out whats wrong first

 

What does the fuel damper do

 

It "dampens" pressure waves in the fuel rail

At 55psi pressure every time an injector closes it will cause a pressure wave to travel back into the rail, if these waves are allowed to reflect off the end of the rail they would build up and cause running issues, the damper is just a rubber diaphragm that absorbs the waves instead of reflecting them, the vacuum line attached is for safety, in case diaphragm leaks.
Its actually called a "pulse damper"

It was added in 1998 and up Rangers when the fuel pressure regulator(FPR) was moved from the engine to the gas tank, the FPR uses a rubber diaphragm so acted as a pulse damper and regulator both when it was on the fuel rail

 

Could that cause this issue

 

I appreciate all your help. I can most of the work myself but I suck at diagnosing the problems

 

No, wouldn't be the damper, if it was leaking you would be sucking in gasoline thru the vacuum hose and you would get Rich codes from the computer

But if its a slow leak, maybe not..................if it did leak over a few days and filled up the vacuum hose, then on startup it would suck the gasoline into the intake and you would get a flooded engine........maybe, long shot
But easy enough to check that vacuum hose for gasoline after it sits a day or two