Very good!

But with respect I have a 2008 Ranger & the fuel system is different.
Different animal all changed now.
The pump & regulator are in the tank.
The filter has a bypass line that returns unneeded fuel back to the tank.
Pressured fuel goes in & is returned right back to the tank if not needed.Maybe to give the pump a longer life?
Just like the old carburetor cars in the 60s
The fuel rail doesn't have a regulator. it has a fuel shock to smooth out the pump pulsation to the injectors.
The PSI is the same through out the whole system, 55 PSI from the pump to the rail.
If a injector was leaking it would have showed up when I changed plugs, it wouldn't get 21 mpg.
Also when the engine is off the fuel goes back to the tank to release the pressure in the line.
When I was doing a PSI test with my gauge it went up to 55 at an idle. I opened the bleed line & dropped the pressure to 22 & it idled just fine. Just to find out what would happen.

I also remember reading if the return line is restricted it will cause hard starting! (my problem was when Hot)

It actually seems better but I'm still critical

 

From your description and investigation into the operating principles of the fuel pump setup and fuel pressure readings it sounds like it is operating as intended. If you are starting better with the new plugs don't sweat it. That should be the end of it.

 

Again, fuel pressure shouldn't quickly drop to zero as soon as the fuel pump turns off.
SO, hook up your fuel pressure gauge so you can view it through the windshield.

Turn the ignition key to on, but don't crank the engine & wait a couple of seconds or so for the fuel pump to run & cycle off, then turn the igntion key to off & post how long it takes the fuel pressure to drop to less than min spec of 56 psi.

Also is the engine cranking speed up to spec & how does the battery voltage under load measure up????

When the engine is cranked, how low is the battery voltage dropping???? Low voltage to the fuel pump, injectors, coil pack & starter motor, can make for starting problems.

If you don't have a multimeter to check the battery output under load & the cranking speed seems lower than it should be, consider running this puppy by your favorite autoparts store for an in vehicle electrical system checkup, via their portable electrical system tester.

It can load test the vehicles electrical system & properly used can spot any serious under load voltage drops in things like the battery, alternator, battery cables, starter motor.

More thoughts for consideration, let us know what you find.

 

Paw Paw,

key on engine off gauge goes to 57
key off gauge goes to 0 in about 2 seconds,
that tells me the filter return line is clear.
battery is hot cranks like a mother #$%ker!

Not bragging, I was an auto electrician,
Certified GMC truck mechanic,
ASE certified in AC & Electric,
16 years Water District Vehicle Maintenance Manager
Retired & bought this truck used & I don't like the way it occasionally cranks excessively to start
But when I heard another crank excessively at the store I think it is a common problem & maybe I should check the throttle body for dirt or buildup.
But since I replaced the plugs it only did that once more.
What do you think.

 

When the fuel pump runs to prime the system, it's supposed to hold fuel pressure for the start. It should hold pressure for hours, not seconds after the pump cycles off.

There is a check valve in the tank mounted pump/regulator thats likely stuck open & allowing the pressure to bleed off right away.
Maybe rust, corrosion, or some sludge gumming it up.

Maybe try thumping the pump with a broom handle, or maybe try adding a 20oz Techron Concentrate Plus treatment to the tank & see if it'll respond.

 

So let me get this straight the 2008 ranger fuel system is like the 1999
or the pump should do exactly as the 99 4.0 ranger?
hold the fuel pressure.
Maybe I better get a Haynes manual

 

Hi Paw Paw

Up date

I bought a manual & it isn't clear about the fuel check valve.
But it says the pressure requirement is 60 to 65 PSI.
Mine is 55.
The dealer (over the phone says right on!) might not have gave a crap about the customer on the phone!
If there is a check valve in the system I want to check it.
You said your psi holds & mine drops.
Of course the book isn't clear about that either, is the check valve in series with the supply, or output hi pressure line from the tank?
If i need to I can take the bed off very easy I have a twin post hoist in my garage.
You said just bang on it with a broom handle? can or would you describe its location to me?
By the way it seems to start really quick when cold & lately it starts about the 4th or 5th beat while cranking only once did it crank long & i turned it off & tried again & it started right up.

 

The check valve is in the pump assy, so just thump around on what ever is sticking out of the tank & see if you can wake it up & get it to hold psi when the pump is turned off. Just don't get crazy with your thumping tool & break something.

Having to cycle the switch to get it to start, the pressure dropping to zero a couple of seconds after the pump turn off & it's pressure being on the low side, sure seems to indicate something is going on with the pump & it belongs on your suspect list.

Those that have changed the pump say it's easist to remove the tailgate to make things lighter, unfasten the fuel filler tube, taillight harness & bed bolts, then set the bed back on the rear tires & the rear end on saw horses. If you have a cherry picker, then it'll be even easier.

Will be interesting to hear what you find.

 

Check fuel filter. Take line off that returns fuel to tank, blow into line, if air is freely blown, so is check valve. Sorry I don't have a manual for 2008. What's the status of the warrenty?

 

I Have a new fuel filter I will try to get to it today.
I will also check the check valve by blowing back on the line.
Sounds like it is bad by your description

We'll see.

Thanks

 

Well Merry Christmas Everybody, (still America isn't it?)
I am updating, I installed a new fuel filter. It was very hard to blow through and I feel it had something to do with hard starting occasionally. Seems to start really quick now.
Then I changed the oil & filter. I went out for a test drive & I got to a 4 way stop out away from everybody. I took off & pinned the throttle. I wound her up to limit, 5800 rpm & it shifted to second & 5800 rpm it shifted again I still held it to 5600 rpm it shifted & i let off & I was going 85 MPH wow just a little 4 cylinder truck! I am very pleased with the performance. I did some driving & used 1/4 tank of gas. I filled up took 3 gal & did the math. 26 mpg an improvement of 5 mile per gal. It is such a nice little truck, it is almost taking first place between my 2 vehicles 2007 Honda S2000 & my little Ranger.,, My friend has a 2005 Ranger & I am going to change the fuel filter for him since I have a hoist, ( us old fuc*s have a hard time getting up from a creeper. It will be interesting if his fuel pressure readings & stuff is the same as on my truck. To Be Continued!

 

The scheduled maintanece on my 2001 indicates change fuel filter every 30,000 miles, so I better get mine done too. Then I can really zip around with my 4.0L, but I'll probably keep it below 3,000rpm. What can I say I'm an old man.

 

.................I have an '08 2.3 , coming up on 31k and have had several times when the starter cranked longer than normal ! So , looks like a new fuel filter is called for . Where is it located , and how hard is it too change ? , thanks , rb

 

Yup, the fuel pressure can be in spec, but if the filter is clogged, flow through the filter can be restricted & that'll throttle high rpm flow demand.

 

The fuel filter is on the drivers side just inside the frame rail about were the drivers seat is. It is stored neatly in a spring loaded hanger. the black line to the engine is the one I took off first. Just take your fingers squeeze the white or light colored clips that hold the coupler to the filter squeeze it together & pull the line off. Fuel will drip for a couple seconds. (No Smoking !) Then I grab the filter by the tube I just took the line from, just pull the filter from the bracket. It will come off & repeat the same way for removing the other lines off. The side that has 2 lines on has a 3/8 supply line & a 5/16 return line to the tank. Some fuel comes out but not that much. If you blow through the filter blow on the supply side (3/8 line) & plug the 5/16 return line. If you don't block it off the gas will blow right back in your face!It should be real easy to blow through after all the fuel is out. If there is a lot of restriction it needed replaced. I had a Oldsmobile when I was a kid, and the engine would starve for fuel. I changed the filter 7 I couldn't even blow through it. Then put the two lines on the new filter slide it into the frame holder & put the engine line on. I always check for leaks by sykling the pump with the key a couple times checking for leaks.