Ive never been able to find out what the problem is with my 4.0 ranger. Ive gone through it with another member from another forum. The car sometimes doesnt want to start when i turn key to the CRANK position. Then all of a sudden it will decide to crank. Sometimes it doesnt crank, sometimes it takes a few seconds, but most of the time the car will decide to crank within 1 or 2 minutes of me sitting there trying to crank it. I have power at the relay, ive tried swapping the relay but still nothing. When i have a no crank putting the car in Neutral will not start it so that rules out the trans neutral switch? Ive tried replacing the ignition switch. That didnt do anything. I dont believe its a PATS issue as the theft light operates normally, it doesnt read like a bad key has been put in. As a last resort i replaced the battery cables with new motorcraft harness. The truck started every second everytime for about a month and a half. Then all of a sudden it started having no crank issue again.

Today while driving down the highway the truck suddenly died. I was low on gas but i dont think that was the issue because i put my hazards on, put it in park and then it restarted with no problem. After it restarted i immediatley put in an obd scanner and it showed no faults. This is the 2nd time the vehicle has "suddenly died" while it was on. The other time was at an automatic car wash. When i drove it through the car wash though i had the drivers wheel liner off because i was inspecting the starter harness. I suspected maybe something got a blast of water (this was prior to changing the battery harness) but now i dont think thats the issue. Other than that i can count up to 2 other occasions where i felt like the truck had an electrical power loss but it was a very fast loss that the truck never actually died. I only experienced a brief hesitation and dimming of the dash lights during those times.

 

4.0l engine, what year<<<<?

Manual or automatic?

These all have different starter interrupts

Define "crank"
To me crank means starter motor is turning(cranking) the engine but to some it means engine starts, engine cranks over, cranks up
So no crank means starter motor was not working, not turning the engine over, so battery or cable issue, maybe starter interrupt, clutch or trans switch


When engine is running all power comes from the alternator
Battery is only used for starter motor, startup

When truck "died" did all the electrics go off, all lights on the dash off?

 

My guess is a bad connection either at the main power line, or a ground. That's really the only thing that'll kill the whole truck.

 

02 auto
Crank- When i turn the igntion key position to start. Where the starter normally engages. Those are the times when i get random "no start", as in the starter doesnt crank therefore the vehicle the doesnt start. It occurs randomly and usually the truck finally "engages" the starter after a minute or so of me putting the key in an out/retrying and the truck starts. When i get the no start issue and i turn the key to [start] the dash lights/stereo seem to cut off.


I cant tell you for sure as i was looking infront of me both times the truck has died. The only thing i noticed is that when i went to press the throttle and i didnt get a response i looked at the dash and the lights were on with a check engine light. The reason im hinting that it is electrical is because there were 2 other occasions in which i was looking at the dash and saw it dim down and felt the truck hesitate like it lost [electrical] power for half a second. But those 2 occasions the truck didnt die completely and it kept going after that brief hesitation.

The battery harness came with a new lead to the alternator, fusebox, a plug of some sort and legs for the starter. I used dielectric grease on the connections.

 

I did replace the battery harness with a new motorcraft one. Prior to that i also cleaned up like 4 ground cables i found in the engine bay including the starter ground.

 

When you turn the key to START position the dash lights, radio and most other electrics will go off, this allows all available power to go to starter motor, so not unusual.
If dash lights DIM but don't go out that would indicate a problem.

Well the only common denominator I can see from symptoms is the ignition switch under steering column, it is a slider switch, and they don't usually wear out

Does the key rotation "feel" OK, no looseness or tightness?
The ignition key turns a lever that pushes or pulls a rod that runs down steering column to ignition switch
The rod slides the ignition switch into it's 4 positions, ACC OFF RUN START, this makes and breaks electrical connections in the switch

The starting circuit is pretty simple.

Ignition switch in START(12v)-------------transmission neutral switch------------PATS relay---------Starter motor

Neutral switch passes the 12v in PARK or Neutral only, so if shifter is loose try starting in Neutral instead of Park

PATS relay, also called starter relay(engine fuse box), is GROUNDED by the computer(PATS) if PATS key is recognized, the 12v from ignition switch/trans switch activates this relay, IF it is grounded
When relay closes starter solenoid/relay(on starter motor) gets 12volt activation voltage and starter motor turns

Ignition switch turns on the computer, and computer runs the fuel injectors, so if computer should lose power, engine would die
But CEL wouldn't be on, computer Grounds CEL to turn it on and if computer had no power then CEL would not light up, but it did, so.............

You may have two unrelated issues
Not enough to go on

I would replace the Starter Relay in engine fuse box just on spec, standard automotive relay, so $5-$8
Make sure column shifter is tight, no looseness, Ford truck column shifters are a known issue, they loosen up, just a couple of screws
Google: ford column shifter

model doesn't matter they were all the same

Dying while driving could be fuel pump, very very uncommon for them to stop when running, usual failure is just not working one day on start up, no warning just dead one day.


Main electrical, like Dustin said, could be another common denominator
As said earlier Alternator supplies all the power when engine is running, battery is not used but is still there.

The batteries Positive terminal will have 2 cables, larger one just supplies power to starter motor, nothing else
Smaller one goes to engine fuse box and it supplies all vehicle power when engine is off

The alternator has B+ terminal on the back, that supplies all alternator voltage to the vehicle

The smaller battery pos. cable and the B+ alternator cable are both connected together in the engine fuse box.
Battery voltage is 12.5v, alternator voltage is 13.5v, so when alternator is running its higher voltage supplies all power and keeps battery charged by providing 1v higher voltage

This connection would be the "main power" for the whole vehicle, and if intermittent, then could cause both symptoms but no CEL would have been on when engine died, because no power anywhere.

 

I did replace the ignition switch thats under the column and not the cylinder. The old one felt like it had some friction to it when i turned the key. I replaced it with a new motorcraft unit. I remember when i had replaced it, it did nothing in terms of solving the no crank issue as it had a no start sympton a day or two later. As of now its buttery smooth.

Ive tried starting the vehicle in neutral when i have a no crank situation but i still get no crank.

Ive tried wiggling both the ignition key and column furiously while having the key in start position. It doesnt seem to do anything in aiding the vehicle to start.

I replaced the starter relay with a ford relay from another ranger that had super low mileage. Ive had 0 issues with that truck. I opened up the old relay on this truck and the contacts did not appear severely worn.

My shifter doesnt feel like its severely loose, it does have some play to it but the truck also has 150k+miles. Ill have to take a second look at this.

As far as the fuel pump is concerned i have always heard it come on even when the truck has a no crank symptom. It started right up after it died yesterday.

I have read battery voltage by means of the cig lighter while runing and it stayed a steady 13.5-14v i cant remember exactly.

Ill have to go over all these points again and get back with you. The part that caught my interest was the pcm grounds. I did just notice under the manual that there is two PCM relays which i will also try replacing. Does the PCM have a ground cable or is it grounded directly to the body?

 

PCM Relay powers PCM(computer) and fuel pump relay

PCM has several grounds, none direct to battery, some are shared internally some are not.
You could use a test light, key off, and probe each Ground wire on PCM connector

You are using the EEC-V PCM which is still used in 2018 Fords, and grounds never changed
Look here to get all the ground pins located to test: 104 pin PCM Pin layout | Ford Explorer and Ford Ranger Forums - Serious Explorations