I have a 2000 3.0L V6 flex ~112K miles has taken a little longer (another second or two) to start lately and occasionally has a rough idle for a few seconds after starting. I know the extra second or two of starting may not sound like much, but we all know about how long it takes to start so you get into a habit of turning that key that amount of time so as not to engage the starter any longer than it needs to. However, now when I go to start it. I turn the key for that habitual amount of time and it will either not start or will stumble at the end and die. Recently on two occasions, it has started and then idles rough for about five seconds.

This extended starting time began to occur not long after changing a battery. I wouldn't think this would be a related issue, but I thought I saw somewhere else about someone discussing a similar issue being something as simple as his negative battery cable/post. Not sure I followed what he was saying because the engine cranks fine and runs OK. But I mention that in case anyone else has insight about that. I have seen other posts related to this and posters often suggest it might be a fuel issue.

I checked fuel pressure today and after priming once I only have about 40 psi. Priming a second time gets me up to ~52 psi. Starting the vehicle puts it up to 60 psi. (Manual says 47-63 psi is the operating range). After shutting off the engine, it drops immediately back down to 52 psi. Allowing that to set for 6 hours drops to 48 psi.

After priming twice today, the engine started right up. So I may just do that until I can fix the problem.

I have seen RonD's posts about looking for a leaking fuel injector, so I can do that test next weekend. I don't smell fuel, so I am kind of ruling out a leaking line.

Is there anything else that I can rule out, like the pump, or could it still be losing pressure overnight at the pump?

I have also seen about checking the fuel damper vacuum line for a smell of fuel. I assume you pull that vacuum line after shutting off the vehicle?

For what it is worth also, I have a slight rough idle that I have tried to isolate, but no DTC codes and fuel trims run about -8 to 10% for long term fuel trims. I always thought it was vacuum leak, but I have been unable to find it. Some say for rangers idle rough, so I have just written it off until it throws a code or gets worse. But just in case that adds anything to the issue, I thought I should mention it.

 

You may have the coil pack starting to fail. Mine has 118,000 miles and was running rough for about 20 seconds every morning, but it wasn't long enough for the check engine light to come on. Then one morning it continued running rough and that's when the check engine light came on. A code test revealed a bad coil was the problem. It was firing very weak on two plugs. That may not be your problem, but it wouldn't hurt to change the coil anyway since they don't cost that much.

 

I drove it home today and let it set for an hour. Then I tried to crank it over while holding the gas pedal to the floor to see it it would even start (testing for a leaking injector). I never really heard it stumble or try to start. Only cranking with the exception of after allowing it to stop cranking you feel that stumble like the engine just shut off. What was strange to me was that it wouldn't start right away after doing this test. I am not sure if that indicates that it used up the fuel in the fuel rail still indicating a leaking injector or not. Just don't understand why it wouldn't start right after that unless the fuel pressure in the fuel rail went somewhere.

But am I safe to assume that I should replace the fuel pump if in the first prime I am not even getting up to the 47-63 psi on the fuel rail? Should I still test every spark plug looking for wetness of a leaking injector?

 

Your "Clear Flooded engine" test would indicate injectors are not leaking

The 2000 Ranger will not have a return fuel line so just the IN line from the Fuel pump at the engine.

If you have or can get fuel pressure gauge again you can prime the fuel system a few times(key on/key off) to get pressure up to 60-70psi
Then softly clamp the fuel line at the engine
Watch pressure gauge, if it stabilizes and holds pressure then rail and injectors are OK
release clamp
If it starts to drop then yes check valve in fuel pump, OR FUEL FILTER, is leaking.

Around 2000 Ford may have still been using the older style return fuel line setup in the gas tank, for these they used a 3 port fuel filter, it had 2 fuel lines going to the gas tank, IN and RETURN, and it had a check valve inside this filter.

Leak can also be in the gas tanks lift hose, but in either case fuel pump assembly needs to be checked or replaced

 

Thanks Ron, yes, it has the 3 port filter. I know what you are talking about by clamping the line. I saw a video recently by South Main Auto https://www.youtube.com/watch?v=DL8toqPcXKA where he did the same thing trying to isolate a fuel loss issue. The only problem is he lost pressure in 2 seconds because the fuel injector was just pouring gas. In my case, I worry the loss is so slow that I would have to leave it clamped for a long time and possibly result in damaging the hose. So maybe the payoff of that test isn't worth the risk to me.

I did have another question. My options are either a Motocraft sending unit which is like $568 plus tax at O'Reillys or $400 at Rockauto. However, I can get a Delphi or Carter sending unit from Rockauto for about $200. The only thing is the Carter or Delphi units are missing a piece that you get from the Motorcraft unit. Not sure what that piece is. I hate to pay that much for the Motorcraft unit, but not sure if that missing piece from the other units having to be pulled from my current sending unit is worth just paying the extra for the Motocraft sending unit?

Go to picture 2 and notice the open hole.
More Information for CARTER P74867S


On the motocraft pump it is the second electrical connection on the top. Go to picture 3
More Information for MOTORCRAFT PFS429

 

Motorcraft tests each part before it is boxed and shipped.

Other brands do not, they provide a warranty and let the buyer test the part.

Up to you on how easy you think fuel pump is to change, odds are other brands will work fine for a long time.
You already know the Motorcraft will work for at least 16 years.
I have original Motorcraft pump in my 1994, so 23 years

Up to you really

If part doesn't match OEM part then find one that does
When you buy a fuel pump assembly it should include all the parts

I use wide jaw vise grips on braided fuel lines and leave them on over night then check pressure in the morning, never hurt a fuel line doing this.

Fuel pressure should hold for MONTHS, so you will know pretty quick if an injector is leaking

 

Well, changed out the fuel sending unit with a unit from Carter. Will have to wait and see if that fixes the fuel pressure loss problem overnight. Otherwise, it runs. The only thing that puzzled me was when I swapped it, I was probably at half a tank of gas. When I started it with the new unit, I am under 3 quarters of a tank but easily more than half a tank. Hmmm. I will see it how goes and just monitor the fuel level by using the trip odometer.

On a more comical note, I bought it from rockauto, should I be concerned that Carter includes a labor warranty form in the box. LMAO