Hopefully you guys can help me out,
I bought a beater ranger for $500, started and ran ok but had a misfire. Anyways I drove it 12 miles home and parked it for the night.
Now when I try to start the truck it fires and runs strong for 2 seconds then dies immediately. Since it fired I assumed it was getting spark and fuel but some sensor was shutting it down. After checking almost everything else I checked the fuel rail and barely any fuel squirted out.
When continuously cranking it will fire and run but as soon as I turn the key to run it dies. I have already replaced the fuel filter, I am leaning towards faulty fuel pump at this point.
I do not have an OBD1 scanner and the auto parts store won't loan them out. If anyone has any ideas I would appreciate the help.
-

 

Welcome to the forum

You know about OBD1, so do you know what the connector for the OBD1 scanner looks like, its in the engine bay

You need to find it, on my 1994 4.0l is on drivers side between fuse box and firewall nearer fuse box, was attached to it on some models, can have a Cover that says "EEC"

Couple of questions first
Does the CEL(check engine light) come on with the key, it should
And it should go off after engine start
And then come back ON after engine stalls................if its not coming back on that means computer has shut OFF, and that's why it stalled

Now lets check fuel pump and relay
Find the ODB1 connector and go here: https://therangerstation.com/tech_library/OBD_I.shtml

Second drawing shows the connector AND a slot labelled Fuel Pump
That slot GROUND the fuel pump relay which should turn on the fuel pump full time, well when key is on full time, lol

So make a jumper wire from a Ground, battery Negative is fine
Turn the key ON(run)

The fuel pump relay is in the engine fuse box, and you should hear it CLICK when you GROUND that slot, put jumper wire in the Slot
And then you should HEAR the fuel pump running in the gas tank
Now try to start engine a see if it stays running




Normally the Computer Grounds the Fuel Pump Relay, but only for 2 second with key ON
After engine starts(RPMs above 400) computer should Ground it full time, this is a safety thing, in case of an accident and fuel line breaks the engine would stall, run out of gas, so electric fuel pump would shut off.
If your computer was shutting off then so would the fuel pump relay, hence the question above about the CEL
If engine stays running with jumper in place then we can diagnose it more.

You can run the engine and drive vehicle with that jumper in place, doesn't hurt anything

 

I have already tried grounding out the fuel pump connector on the OBD sensor. The relay clicks and the fuel pump runs but I am still having the same issue.
My suspicions lie in
a weak fuel pump
Timing being off
ICM not being grounded properly

Things I have already checked with a meter
MAF
IAC VALVE
ICM
Crank sensor
02 sensor
Fuel pressure regulator
Major vacuum leaks
Both ignition switches
Relays
Grounds
Plugs/coils
Inertia switch

Thank you for your help so far,

 

Update I replaced the fuel pump and pressure has increased quite a bit but I still have the same issue fires and dies after 2 seconds.

I have a fuel pressure gauge and OBD1 scanner on order but I would like to try and solve this asap

 

Just to see if its spark or fuel thats shutting off

Pull off the air hose on the intake manifold, MAF sensor is not need for startup
Get a can of quick start(ether) or some gasoline in a spray bottle
Have a friend start the engine while you add, spray, fuel into the intake manually

See if you can keep it running by adding fuel manually, if so then injectors are shutting off
If it still stalls then spark is shutting off


Also unplug the 3-wire TPS(throttle position sensor) and try to start and see if it stays running
Its a long shot but have run across it once, but only once, and it was on a 2.3l
TPS gets 5volt key on, it sends computer 1volt throttle closed and 4.5 to 5v throttle WIDE OPEN
If computer see WIDE OPEN and 0 RPMs, it will shut of fuel injectors, this is call "Clear Flooded Engine" mode, all fuel injection computers have this

So if TPS was shorted or it wires, computer would shut off fuel injector

 

So I unplugged the TPS and sprayed starting fluid in the intake after the MAF same deal, fires for 1 to 2 seconds then dies.
I noticed the kid I bought the truck from broke 2 bolts where the ICM mounts near the fuel rail and had it zip tied on. I am in the process of drilling out and tapping the bolt holes but for now I ran 3 grounds off of each hole to the battery. Would having it loose cause issues not to start?

 

Which one

"2 seconds" or "as soon as you release the key" ?

 

As soon as I release the key, if I hold it in crank it continues to fire and I can increase the rpms.
I just tested voltage to the injectors I am getting 12v

 

Well you are losing Spark, for sure, so not a fuel issue

2011Supercab may be on to something

Test Coil pack for 12volts with key on, the Red/light green center wire on either coil pack

The ignition switch under the steering column has TWO different power paths for coils and ICM
So it may be cutting power to coils and ICM in RUN, but works in START

 

Solved, the second switch where the linkage connects to, was loose. Thank you guys for your help!

 

??

Good work but what is the "second switch" and the linkage?

 

When you turn the key it pushes a linkage arm which pushes the internals of a switch halfway down the column, its acting up again so I'm not %100 on it yet

 

Thats the ignition switch, a slider switch

Rod from key switch to ignition switch is call the actuator

 

OK so I'm back to square one, I replaced the ignition switch since it was only $15 and the old one was pretty corroded on the inside. Same problem though, is there anything in the actuator that could cause this?

 

I tested the center wire on both coils with the key on run, I am getting 12v.

 

The same Red/light green wire should also be on the ICM, they are all spliced together, and it should also have 12v with key on.

Also turn key to START then back to RUN to see if the 12volts is still there

You are close
Coils have voltage
Crank sensor is working or it wouldn't start at all
All that's left is the ICM

 

12v on the red/green wire of the ICM with key set to run before and after trying to start it.
I did mention before the previous owner broke two of the bolts where the ICM mounted to the intake. He only had it ziptied on, I ran a ground wire out of each hole to the negative battery post. Just wondering if it being loose would cause it to kill spark? ☹

 

It would not allow spark, but you have spark, but it stops

 

Correct, its like all power is being cut to the coils

 

Try starting it with just one coil hooked up, try it with one, then the other.

 

No change

 

Any ideas in where to go from here? I talked to the previous owner and said you had to move the key back slowly in order for it to run. I tried that many times, still the same outcome.

 

No, can't think of anything

You know its a lack of spark, from the test of adding fuel manually

You have tested for voltage at the coil and ICM with key on start and run
The comment by previous owner would indicate lack of voltage from ignition switch in run but you have changed the switch, and you have tested for 12v at coil in any case

Only other thing I can think of is to do the voltage test on Red/light green wire(coil) in a Live test, hook up volt meter and have someone try to start engine, volts should drop down to 9.5-10.5 volts when cranking then popup to 12.5-14volts after startup, not drop lower

You could unplug 3 wire connector on alternator, that will prevent alternator from working after start up, just in case it has damaged rectifier and it sending out AC voltage, just thought of that

 

Could it be a ground? It started and drove fine when I picked it up, not sure if I broke a wire or something when I was under the hood.

Is the EEC relay out of the question?

 

EEC Relay powers computer and fuel injectors but not Spark

When you turn on the key that red/light green wire from ignition switch powers coil, ICM and crank sensor, directly, same wire also turns on EEC Relay which powers up computer and injectors

EEC Relay can't effect spark, but can effect fuel since EEC relay also powers up Fuel Pump Relay and injectors

Only the exhaust side coil works when cranking engine, so you could unplug the intake side coil pack wires and insert a jumper wire to the center Red/light green wire, then run that jumper to Battery Positive, like "hot wiring" a car in the old days, lol

Then try to start, the 12volt will back feed to all the components on that red/light green wire


Can't see a ground being the issue if spark works with key in START position, the ICM doesn't have a separate START and RUN wire like the older TFI modules did, so either the Ground works or it doesn't, can't see it "switching" ground paths between start and run
Its possible, because ICM does activate intake side coil pack at 400RPM so it is "aware" of startup