2004 Ranger 4.0 turns over, won't run

[04Ranger]

I've replaced the mass airflow and crank position sensors, nothing, no codes either. Replaced fuel pump last summer. Also checked relays and fuses. Nothing there either. Note: a/t going out.

fuel pump? fuel filter? tcm?

any insight will help.

thank you

 

[RonD]

Welcome to TRS

If starter motor works then its not a PATS(passive anti-theft system) issue, no rapid flashing Theft light on the dash.

So do the 50/50 test
Spray gasoline or Starting Fluid into the intake and try to start engine.

If it starts and dies then fuel is the problem
If it doesn't start then Spark is the problem
50/50 quick and easy

 

[04Ranger]

already knew it wasn't anti-theft.

as far as fuel, checked relay, ok. tried pumping it cranking and could smell gas, plus I replaced fuel pump last yr. but.. I've bought brand new parts in the past and they were defective right out of the box or went bad real soon. so I'm leaning towards bad fuel pump.

but.. I'll check spark next.

however, when I did put new mass airflow sensor Fri, it fired ran for about 2-5 seconds, then died. wondering if it's possible something burned up new sensor right away. don't know what it could be, if even possible.

tried my code reader, nothing. last yr when it did this it was the mass airflow sensor, turns out it was dirty. cleaned it off, ran like new. code reader read nothing that time as well.

today's engine tech is superior.. until it messes up, at which time I wished it just had a points dist and coil. lol

 

[RonD]

Just do the "old school" 50/50 test, that does spark and fuel test BOTH at the same time.
Then investigate from there

There is no accelerator pump with fuel injection, so there is no "pumping the gas pedal" to add more fuel.
It is truly an "air pedal" now, it was partly a gas pedal when we used carbs but primarily an air pedal even then.

 

[04Ranger]

no accelerator pump with fuel injection

true, there is no accelerator pump, but you can flood an efi system by pumping the peddle. done it many times on various vehicles. I had a tbi Topaz 4cyl once the only way it would start would be to pump and or hold down the pedal, especially in the winter. I had an 86 GT that I had to pump it a couple of times in the winter as well.

I also had an 88 Ranger 2.9 efi 4x4 that the fuel pressure regulator went out a couple of times that mimicked the problem I'm having now, but would flood until I changed the regulator.

the problem is, I need someone else to turn the key on so I can lay under the truck to listen to see if the pump is even running until it builds up pressure. I'd rather not just drop the tank if I didn't have to. of course I could cut a hole in the bed for direct access, make a flap from the cut out like some do.

back in the day, things like this were so much simpler to diagnose rather than depend on a code reader.. which could be wrong.

 

[crazy horse]

I’m having the same problem on my 92 4.0.

You can turn the key on, and for a few seconds the fuel pump should kick in.
If your rpm dial jumps up to 500, your computer is reading the motor turning over, thus your crank sensor is working. If you jump power from your fuel relay to turn on the fuel pump, you know that your fuel pump works and inertia switch works. The 50/50 gets you ahead of the game knowing if it’s spark or fuel too.

There’s so many test and ways this thing can go.

 

[RonD]

true, there is no accelerator pump, but you can flood an efi system by pumping the peddle. done it many times on various vehicles. I had a tbi Topaz 4cyl once the only way it would start would be to pump and or hold down the pedal, especially in the winter. I had an 86 GT that I had to pump it a couple of times in the winter as well.

I also had an 88 Ranger 2.9 efi 4x4 that the fuel pressure regulator went out a couple of times that mimicked the problem I'm having now, but would flood until I changed the regulator.

the problem is, I need someone else to turn the key on so I can lay under the truck to listen to see if the pump is even running until it builds up pressure. I'd rather not just drop the tank if I didn't have to. of course I could cut a hole in the bed for direct access, make a flap from the cut out like some do.

back in the day, things like this were so much simpler to diagnose rather than depend on a code reader.. which could be wrong.

You can hear a Ford Fuel pump in the cab, turn radio down, it is not quiet, you will hear the HUMMMMM, if you don't then fuel pump is not getting its 12volts

How a Gasoline engine works hasn't changed at all, since late 1800's
You need compression to heat up and vaporize the gasoline
You need a spark to ignite that gasoline vapor
You need the correct air/fuel mix so gasoline vapor can ignite and burn

All the electronics were added to make the spark and air/fuel more reliable and more efficient.

DIYers tend to focus on the electronics, which is the wrong method of approach, for two reasons, one is that they are way more reliable than mechanical parts, and two, electronics are monitored by the computer which will let driver know if something is out of spec, code will be set.

Old School, its still just a gasoline engine, the above 3 things make it go, compression, spark and fuel
spray gas into the engine and see if it starts, easy peesy lemon squeezy, and you are half-way(50/50) to knowing the problem

 

[AdirondackRanger]

inertia switch?

 

[crazy horse]

Wierd, my posting disappeared. Yes, inertia switch, it’s on the passenger side, under the dashboard. It can stop power to the fuel pump if triggered. I doubt that is his problem, but don’t rule it out. I’m just talking about the diagnostics that I did.