My 2005 Ranger 3.0 sometimes does not start when cold, or runs for a second and dies out. At first, turning the ignition key on and waiting 3 seconds and repeating 3 times would make the truck start but now it's worse.

OK, I think I did my homework and have checked everything below.

With the key on I check pressure at the schrader valve. Pushing in on the pin releases a squirt of gas, then nothing. (I don't have a pressure gauge)

I pulled the fuel relay. 12 volts measured at the plug OK. I also checked the relay by energizing it, hearing it click, and checking continuity across the other terminals. It tested OK.

I went to the safety shutoff switch, removed the switch and measured 12 volts at the terminals. I checked the reset and checked continuity and it checked OK.

I made a jumper and inserted it into the safety switch and when I tried to start the truck, it fired for a second then died. Rotating the ignition switch on and off repeatedly as above and it finally started. (coincidence?)

After the truck was warm I shut it off and removed the jumpers and replaced the safety switch. The truck started fine. I went to the safety switch and pulled in and out on the plug and wiggled the wires to see if there may be a bad connection. Nothing.

Also, during all this I also disconnected the battery and waited before reconnecting to clear the system. (just in case)

So there you have it, can you help me?

*Update - once running I let it run for 20 minutes and shut it off. It restarted no problem but after letting it cool off for 30 minutes it would not start without cycling the ignition key repeatedly and finally on the 1oth try it again started.
Also, I changed the fuel filter.

 

Fuel pump only runs for 2 seconds each time key is turned on.
2 seconds of Fuel Pump running increases fuel pressure by 10-15psi

Normally a fuel injection system will hold pressure for a few MONTHS, not hours, days or even weeks...............MONTHS

Your 2005 system runs at 65psi, when key is off pressure should hold between 45-55 psi

Turning key on once, normal startup, should put system back at 60psi at least, it can run OK down to about 30psi

So by turning key off and on 3 times you get 6 second of fuel pump pressure so 45psi and engine should start.

Once engine is started, above 400RPM, fuel pump comes on and stays on, so back to 65psi.

If you do not smell gas, and MPG is not in the toilet then fuel pressure is leaking out IN the gas tank.
This is not a power/voltage issue, because once fuel pump is on full time truck runs fine.

Leak could be the check valve inside fuel pump, most likely, or a broken fuel line in the tank, riser pipe.

You can cycle the key on and off as many times as you want to build up pressure, doesn't hurt anything.
But if it is loosing 65psi pressure in 30 minutes it is a pretty fast leak, and if you delay between cycling key on and off you start losing pressure again............

I doubt it would leave you stranded as long as you can cycle the key on and off fast enough for it to hold a bit or pressure so it can start, but I would pull off the bed or drop the gas tank to have a look sooner than later.

 

Thank you RonD,

I put that pump in 2 years ago and the problem started right after. At first it was only occasional and I didn't mind doing the key cycling maybe once or twice a month but now it's every time it sits for a little while. I may have gotten a bad pump or I screwed something up putting it in. Naturally I hoped to save myself the work of taking off the bed but it looks like thats where I'm headed. Any tips on how to check the pump once I've got things opened up? Is that check valve something that can be fixed or am I looking at another pump?

 

Check valve is IN the pump so part of it, not a separate piece.

Fuel pump assembly is one of those parts that it is better to get a Ford original part(OEM), i.e. Motorcraft fuel pump assembly

Reason being it is a pain to replace, and 3rd party fuel pumps have a higher failure rate percentage.

Yes if you just replaced the pump last time and not the whole assembly then you could have a broken/split hose in the tank, and it is just gotten bigger over time.
Or maybe the new assembly had a split or cracked hose.

After you have the assembly out you could blow thru the top tank hose and see where it is leaking air.
Your lungs can only generate 2psi of pressure so an air compressor might be better, but you should at least be able to see if it will hold pressure.

Motorcraft fuel pump assemblies will run $250-$350, so twice the price or more than 3rd party, choice is yours

 

It was the whole assembly. I will try with air as you said.
Thanks again.

 

It should hold at least 60psi for a long long time, as said months and months

 

Curious also, would a full tank of gas or close to empty have an effect? Thats when it is most common.

 

Well, I may have fixed it with the last thing I did - a new fuel filter. After changing the filter it took a little to get it to start and stay running. I suspected it was purging air from the lines but I don't know. Anyway, once running it seemed OK. I used it the whole day shutting it off and restarting at different stops during the day. It always started right up. This morning after sitting all night (the real test) it again started fine.
I thought I had changed this filter when I put in the new fuel pump 2 years ago and have put on less than 10,000 miles so didn't suspect it but I guess the filter was much older after all. I hesitated to change it because I always get frustrated messing with those new-fangled fittings that need the special tool. After composing myself I found the fittings came off pretty easy once I got a feel for the little push- pull thing you have to do. Anyway, it's running and I hope it stays that way cause I hate pulling the bed off.
Thanks, Andy

 

Because fuel pump/pickup is at the bottom of the tank a full fuel tank will have the ability to hold pressure.
"A pint is a pound the world around", 8 pints in a gallon, so a gallon of gas weighs 8 pounds.

15 gallons is 120 pounds so that can hold some pressure in the system.

Unless it was a 3 line fuel filter there would be no check valve inside, so that wouldn't be your problem.
Old one could have been leaking, but you should have smelled that

 

Since changing the fuel filter the truck has started every time. This morning after sitting for a day and a half it again started right up. It did not appear to be the original filter and the truck only has 110K miles, but it's working!

 

Well that shouldn't work but glad it did.

Thanks for posting the update and the fix.

Maybe Ford added check valves in the newer fuel filters, wouldn't be expensive and would solve long term issues with failing fuel pump check valves in the Returnless system

 

Over a week now and no problems. I'm wondering still why this worked or more, why should it Not have worked?
Wouldn't a clogged fuel filter keep the fuel pump from getting enough fuel pressure to start the motor?

 

Yes, clogged fuel filter would, and engine wouldn't run well above 2,000RPMs either, so it would stall out on the highway, if filter was that clogged.

Assuming the only check valve is in the fuel pump and the only outlet in the system is the fuel injectors, then loss of pressure would be 1 of 3 things
1. broken fuel line, you would smell that
2. leaking injector, computer should set Rich code for that
3. leaking check valve, no code for that, or smell.

Clogged fuel filter is generally noticed at highway speed first, when trying to maintain 65mph for extended period the filter simply can not pass engine fuel to satisfy engine demand so power starts to drop, "feels like it is running out of gas" is often the comment used for that.

 

I never noticed hesitation while driving but that's because all my driving is on US1 in the Florida Keys. It's rare I go over 45mph which is the speed limit most places.

I thought, maybe I should put the old filter back in and check to see if the problem comes back, and then I thought, Naaaahhh.

 

It's back.
Is there any possibility that one of the sensors, MAF or whatever, could be shutting off fuel or is my only real option to pull the truck bed and change the fuel pump, Again?

 

2005 Ranger 3.0l doesn't have anyway to monitor fuel pressure, computer does monitor fuel pump power, either that wire has voltage or it doesn't, so nothing fancy.

And if it doesn't have voltage when it should then computer will turn on CEL(check engine light) and set a code for no voltage to fuel pump.

This voltage test is from the Fuel pump relay in the engine fuse box, not back at the fuel pump itself, so the wire from engine fuse box back to the fuel pump could be bad and computer wouldn't know that, but that is very very unlikely.
Fuel pump issue is way more likely.

 

Thanks RonD,

I need to stop messing around before this thing leaves me stranded in a bad way. Correct me if I'm wrong but I suppose what I need to do is borrow a fuel pressure gauge and check both pressure when I turn on the key and how long it holds pressure. I put my ear to the gas fill tube while someone turned the key on and heard the pump run as it should. I thought I could hear the pump from the cab but wanted to make sure. So with that confirmed, it's all about fuel pressure, right?
I probably shouldn't ask but could it be the mythical "vapor lock"?

 

Vapor lock was more common on carb engines because they had 0 pressure or 7psi pressure in the metal fuel lines that ran next to the exhaust pipes.
On very hot days the exhaust pipes would heat up the metal fuel line and cause gasoline inside to become a vapor instead of a liquid, this increased pressure in that line and prevented new fuel from flowing in.

Other "vapor" lock could be from engine getting too hot(intake manifold) and gas inside the carb would start to vaporize, so float bowl didn't have enough liquid gas to feed the engine.


Fuel injection requires higher pressure, 30psi minimum, your 2005 runs at 60-70psi, and as you increase pressure on a liquid you also increase its "boiling point".
Your cooling system uses that principle, the 14psi rad cap raises coolant boiling point by 40 degrees.

With the higher fuel pressure you would almost need an open flame directly on the metal fuel line to increase temp high enough

While vapor lock on a fuel injected engine could happen in theory it would be so far down on the list of possible problems that I wouldn't ever even consider it unless I lived in 110+ degree area and problem only occurred in the heat of the day.
But even then I would look at the electronics first, it doesn't like heat either