Weird no start experience

[RCC]

My 96 4.0 ranger suddenly wouldn't start. Crank fine, plenty of gas, no blown fuses, loose connectors or suspicious DTCs.
Didn't hear fuel pump run but gas squirted out when pressed Schrader valve on fuel rail. Before checking anything else I tried one more time and old truck fired right up!
Hasn't happened again since.
Like to hear some blue oval opinions about this weird incident.

 

[ekrampitzjr]

You might have a fuel pump about to fail. Some start behaving as you describe when they're close to failure.

Might be worth replacing your fuel filter if you haven't done that lately. Trash in the line could have been a problem too.

 

[Eddo Rogue]

Vapor lock or fuel pump on its way out...I am having a fuel pump problem as well...keeps blowing the 30amp fuse if I hit a bump just right.

 

[RCC]

That was my first thoughts. Both were replaced and tank flushed ≈10 yrs ago.
Probably time for new fuel filter.
Way it lit off soon as purged rail makes me think pressure regulator stuck. ???

 

[RonD]

My 96 4.0 ranger suddenly wouldn't start. Crank fine, plenty of gas, no blown fuses, loose connectors or suspicious DTCs.
Didn't hear fuel pump run but gas squirted out when pressed Schrader valve on fuel rail. Before checking anything else I tried one more time and old truck fired right up!
Hasn't happened again since.
Like to hear some blue oval opinions about this weird incident.

Watch the CEL(check engine light)
Key on and CEL should come on, this means computer has booted up OK
Crank engine to start, CEL should go OFF as soon as engine starts to spin, this mean computer is getting a good crank sensor signal(timing signal) and will start spark and then fuel injectors

There is no connection between START system and computer, the only way computer "knows" you want to start the engine is when it "sees" a valid timing signal from the crank sensor, it then turns OFF the CEL and turns on the spark and fuel
If CEL stays on when cranking then computer is not even aware you are trying to start the engine

 

[RCC]

Good triage info.
I pulled up codes with OBD scanner when truck wouldn't start to see if it threw crank, cam, ignition or pcm DTCs. Past experience on 90s rangers with bad fuel pump didn't show code. Seems like there should be one for that too. Maybe on later models...

 

[RonD]

Correct, there is no fuel pump monitor, computer does monitor if fuel pump's 12volt wire gets 12v but that's it
There is no fuel pressure sensor, so dead fuel pump that's getting 12volts would not set a code

 

[RCC]

Friend had 98 ranger 4wd that got hard to start. When did fire up it ran poorly. Looked at data stream and short term fuel ratios were sky high. Didn't have gauge to read fuel pressure so yanked pump. Placed pickup in bucket of gas, connected 12v and
thing work fine. Problem turned out to be split in plastic line someone rigged between tank and filter. Taught me never blame pump before check simple stuff first.

 

[PetroleumJunkie412]

Placed pickup in bucket of gas

Strangest repair procedure ever, but glad it worked.

 

[RCC]

That's the irrational methodology when someone is hurrying you. Haste makes Waste. I don't even try to help people like that anymore.

 

[RCC]

Thread went astray. Began as plausable explanations for no-start condition remedied by simply purging fuel rail. Freak coincidence won't cut it. Want technical hypothesis...

 

[RonD]

Was there air in the fuel rail?

If so then you may have a hose in the gas tank with a crack, when fuel level is low enough cracked hose will suck in air when pump is on, but should also cause occasional stumbling when driving
If it was outside the tank you would smell the fuel leak

Bad gas
All gasoline has some water in it, bad gas is when there is too much water
Water and gasoline can't mix
Water is heavier than gasoline
When vehicle sits the water will settle to the bottom of the tank, where fuel pump pick up is
So on startup fuel system gets a big gulp of water
Water is not "fuel", lol

Ethanol can and will mix with water, which is why its in Winter fuel, prevents any water in the fuel from freezing in temps under 32degF
Ethanol bonded with water can also carry the water out thru exhaust without engine stumbling as it will still burn like a fuel with water bonded to it

How can you know you have/had bad gas, you can't, unless you test it by putting some in a clear glass container and let it settle for a few hours, you WILL see the water line form at the bottom of glass container
Or on a no start, pull a spark plug and try to light the WET tip with a match/lighter, gasoline burns fast and bright, water not so much, lol

Gas station all have water settling sumps in each of their under ground tanks, and they are pumped out weekly, or should be, but it is money out of their pocket since they pay for gas same as we do, by the gallon
Avoid getting gas when you see a refuelling tanker dumping in gasoline, that can stir up the water at the bottom so you may end up with more water than usual
Gas pumps also pull the fuel from the bottom of under ground tanks

 

[RCC]

You're either fomoco tech or learned old gear head like me. Replies are in depth and precise.
Didn't notice any air, debris or water exit when purged fuel rail and ran fine afterwards on gas already in tank. Always buy it at stations where I've never had problems. Add injector cleaner once a month for good measure.

 

[RCC]

Rarely let tank drop below ¼. Majority of fuel system problems/pump failures I've seen were in vehicles frequently run low or out of gas. People don't realize it keeps electric pump cool too...

 

[RCC]

Haven't heard anything about my stuck fuel pressure regulator comment. Know that can cause all sorts of start/run problems. Apparently they don't malfunction often since it's not mentioned as possible cause.