So ive been looking around the forum and couldnt really find anything similar to my issue. I went to start the truck up today and it would crank but wouldnt turn over. Batteries are good, and if i hold the gas pedal down it will turn over and run, but as soon as i let off the gas pedal the engine dies. Any ideas?

 

have you thoroughly cleaned out the throttle body and idle air passages

if it starts with the gas pedal mashed , then the idle air port is plugged up , or the idle air controller has failed

 

I just pulled the IAC off to see if there was a lot of build up in it, and there wasn't. where is the idle airport?

 

although this article shows a supercharger install , scroll down and the diagram will the IAC location

INSTALL MANUAL: Ranger/B4000, 2Dr Explorer, & GEN1 Sport Trac | ModdBoxModdBox

it is on top of the throttle body bolted to the front of the intake manifold

 

Reads more like a computer problem or TPS problem.

All fuel injected engine have a "clear flooded engine" Mode in their computer.
To put computer in this Mode:
turn key to RUN(on)
press gas pedal to the floor and hold it there
turn key to START, Crank engine
Engine should NOT start

What each step does:
turn key on, computer starts and sends 5 volts to TPS(throttle position sensor)
press gas pedal to the floor, TPS sensor sends above 4.5 volts back to computer, this sets "clear flooded engine" Mode.
"clear flooded engine" Mode turns OFF the fuel injectors, but leaves spark working.
crank engine, with no fuel coming in engine will not start but any flooding will be cleared by spark plugs.

A properly working TPS gets 5 volts from computer, if your foot is off the gas pedal the TPS sends .6-.9 volts back to computer(under 1 volt).
As you press down on the gas pedal this voltage increases until it gets above 4.5 volts which is WOT(wide open throttle).

TPS has 3 wires, usually a top, middle and lower
Top is 5 volt, 4.8-5.0v is fine
Bottom wire is Ground
Middle is the return voltage, what the computer uses to determine how far the throttle is open.

If your TPS is sending computer above 4.5v when foot is off the gas the fuel injectors are off, to test this without volt meter just spray some starting fluid(ether) in to the intake, crank engine, if it fires then it is a fuel issue.


Now when you say "it runs", what do you mean?
does it just idle or does it rev up like your foot is to the floor or does it just fire once in awhile

 

thanks for clearing that up ron

i lost all my diagnostic info when my O.S crashed in february ( linux go figure )

 

When i turn the key "as if to start the engine" it wont turn over, but when i hold the pedal down it will fire. When i get it started i can control the RPM`s like normal but as soon as i let off the pedal the engine just dies. I looked at the throttle body and it looks clean the IAC looks clean. I think i should also mention that when im holding the pedal down to keep it running there is a very strong fuel smell. When i opened the throttle body swash plate " by utilizing the spring loaded lever attached to the throttle cable" and shined a light in there it looked pretty wet.

 

throttle position sensor

disconnect the throttle position sensor connector , then mash the pedal and start the engine ( if it will )

i would say that TPS is NOT communicating with the ECM

 

Well that's a bit different.

So the "Clear Flooded Engine" is working, so TPS probably is as well.
When you hold the gas pedal down all the way the fuel injectors are shutting off, this stops some of the flooding and allows engine to fire up, but it will flood out again at lower RPMs.

Couple of things you can do to test for the problem.
At the end of the fuel rail is the Pulse Damper, it will have a vacuum hose attached, remove this hose and check it for fuel, there should be none.
If Pulse damper diaphragm leaks that vacuum line is there are a safety feature, so fuel won't leak onto hot engine, but it will flood the engine if that happens.

Next is to check for leaking injectors.
Let engine sit for awhile.
Disconnect coil wire connector, you want no spark
Turn on key
Press gas pedal to the floor and hold it there
Turn key to START
Do not release gas pedal
Crank engine for about 20 seconds
turn key off
Now pull each spark plug and look for one that is wet with fuel

 

I'll get on that an report my findings. Thanks gents

 

Well, all six plugs are dry, and the vacuume hose was dry aswell. Just to make sure the fuel dampner is on the opposite side of the throttle body mounted with two bolts and has a steel braided line with a red vacuume hose right? Im at a loss with this. Any other ideas, maybe it might be the TPS and the ECM??

 

i am thinking it is the TPS sensor , it may not be communicating with the ECM when the throttle is at the idle position

dis-connect the TPS sensor connector and check the TPS electrical connectors for continuity

especially when the throttle at idle position

 

I hate electricity so I have never really troubleshot wires, I should check the plug right? While the ignition is off? Kind of a dumb question but you gotta ask em sometimes

 

Yes, that is the Pulse damper.

You won't get into to much 'trouble' with battery voltages.
Although shorts can get a little scary, lol

Do you have a volt meter?
They are not too expensive.

You can take a sewing pin, straight pin, and pierce the center wire on the TPS, this won't hurt the wire and you will then be able to read its voltage.
Set voltage meter to 20vDC(20 volts +/-)
Turn key on, leave engine off
Touch the black meter wire to engine or bracket metal part, a Ground
Touch Red meter wire to the "pin"
You should read about .9volts

If you have a 3rd hand, lol, or can secure the ground wire, slowly open the throttle and watch the meter, voltage should slowly go up, no jumping around, until throttle is open all the way and meter shows 4.7volts(above 4.5v)


Another test to try is to unplug the MAF sensor, it is on the air cleaner, and there are 6 wires on your year, 4 for the MAF and 2 for the IAT(intake air temp) sensor.
See if it starts normally with that unplugged

 

will a multimeter work since im checking for voltage?

 

yes a multimeter is perfect , you can use it to check OHM`S resistance between both positive connectors and the ground connector.

this will tell you if the TPS is worn out and no longer providing info to the ECM

you will need someone to turn the throttle linkage while you check the resistance on the multimeter

display

( disconnect the battery positive lead before you do anything )

 

Ok so I checked the voltage at the plug " with the black lead on the center terminal and the red lead on either side" initial check was .89 as I opened the throttle it slowly went up to 4.2 at full throttle. 2nd check was the ohms at the same plug with the same lead position I got a reading of 262.0 then i unplugged the MAF sensor and still no start.😪

 

unplugging the MAF sensor will result in a no start , that is the way it programmed i think

plug the TPS sensor connector back in , turn key ON but no start

now using 2 sewing needles as RON D said , take another OHM`S reading from both positive TPS leads

you are checking both TPS positve leads ( one at time )

262.0 ohms is way too a high reading when throttle is at idle position

 

just a side note, this just crossed my mind i got a half of tank of fuel on my way hme the day before this started could i have water in my fuel and thats whats causing this?

 

if that was the case , the engine would try to fire up

 

I'll do another ohms check tomorrow, what is the difference between a good and a bad reading. I hope the TPS is the problem.

 

the only way to tell , is that you would have to compare ohm`s readings between your present TPS sensor and a new one

take the tps sensor to a ford dealership and compare the 2 readings between old and new

a maf sensor will not trigger a no start from what i remember

 

Yes, unplugged MAF sensor will cause Engine light to come on and cause computer to use pre-set fuel/air mixes, but engine will start and run without MAF sensor connected.
Point of disconnecting it is to force computer into "pre-set" fuel/air mix.

Yes, bad gas could cause a no start, but when it did start you would usually see whitish "smoke" coming from exhaust pipe as the "water" burned, there was no mention of that and it would be noticeable.

 

Ok, there hasn't been any white smoke so I guess I can rule out bad fuel, after I do the ohms check on the TPS, what's the next thing to check? Do you guys feel like we're getting close to something haha. Troubleshooting= frustration

 

when the engine is at idle , ohms reading should be high then decrease when the throttle is turned to wide open , that is how voltage / ohms resistance works

voltage rises , ohms resistance decreases , that is how the ECM determines throttle position