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Bronco 2 crank no start sometimes

WVUxZJLx

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I have an 86 bronco 2 with the 4.0 ranger engine, it will start sometimes and other times it wont. I have changed about everything and I believe the problem lies in the ignition possibly. I was told that sometimes there is a problem where if you turn the key too far the car will not start just crank. After being told I was able to start the car a few times so I replaced the ignition. After that got the car to start a decent amount of times in a row. Then it wouldn’t start again. About every 10-15 tries I could get it to start following a backfire. New coils plugs ecm cps etc. No clue what to do. Car runs perfect when it does start. Not a fuel problem
 


alwaysFlOoReD

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You replaced the ignition tumbler? Or the ignition switch? The first the key goes into. The 2nd is down the column above the gas peddle. The switch can get loose and slide up or down the column and cause your symptoms .
 

RonD

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Welcome to TRS :)

The 4.0l OHV EDIS-6 spark system is fairly bulletproof especially for start up

Did you/they add a CEL(check engine light) on the dash with the conversion, it would be helpful if its there and working
If you have a CEL it should come on with key on, and then go OFF when engine starts to turn, that means spark has started
If CEL doesn't go off check/replace Crank sensor

Do the "crank, no starts" only happen cold engine, or warm engine, or doesn't seem to matter?

Is there a set "waiting period" for it to startup again, or do you just keep trying and it eventually starts?


I know you said its not fuel related but I would do the 50/50 test just to be sure
Next No Start
Spray fuel into the engine manually, gasoline, Quick start(ether), carb/brake cleaner, ect......
Try to start
If it fires up and then dies you have a fuel delivery issue
If it doesn't fire then its a spark issue
50/50 instant results
 
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WVUxZJLx

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You replaced the ignition tumbler? Or the ignition switch? The first the key goes into. The 2nd is down the column above the gas peddle. The switch can get loose and slide up or down the column and cause your symptoms .
Both have been changed and looked at but will double check
 

WVUxZJLx

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Welcome to TRS :)

The 4.0l OHV EDIS-6 spark system is fairly bulletproof especially for start up

Did you/they add a CEL(check engine light) on the dash with the conversion, it would be helpful if its there and working
If you have a CEL it should come on with key on, and then go OFF when engine starts to turn, that means spark has started
If CEL doesn't go off check/replace Crank sensor

Do the "crank, no starts" only happen cold engine, or warm engine, or doesn't seem to matter?

Is there a set "waiting period" for it to startup again, or do you just keep trying and it eventually starts?


I know you said its not fuel related but I would do the 50/50 test just to be sure
Next No Start
Spray fuel into the engine manually, gasoline, Quick start(ether), carb/brake cleaner, ect......
Try to start
If it fires up and then dies you have a fuel delivery issue
If it doesn't fire then its a spark issue
50/50 instant results
They didn’t add CEL, have checked multiple ways and fuel supply is good just no spark or signal to spark, and doesn’t seem to matter if cold start or not. No real waiting period
 

RonD

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Have a good look at the crank sensor and its tone wheel
Tone wheel looks like a gear, it's on the back of the crank pulley, it has 35 teeth and one missing tooth, so 1 tooth every 10deg(360deg) - 1
The missing tooth "gap" is how the spark/computer tells when engine #1 is at TDC

The sensor is a VR(Variable Reluctance) sensor, its generates its own AC voltage as the metal teeth pass by it
This sensor is connected to the EDIS-6 module directly

Make sure tone wheel is spinning true, have someone crank the engine over while you watch it, no wobbling
Check that the crank sensor is not touching the tone wheel should be a small gap between sensor and teeth
Check that the "gap" in not full of mud/dirt
Change sensor if you want, $20-$30, check its wiring back to EDIS-6, 2 wires with a shield wire

EDIS-6 module is connected directly to the Coil Pack
So engine computer is not involved in spark directly, EDIS-6 runs the spark system

EDIS-6 does send the computer the crank sensor's timing pulse(gap) so computer can time injectors
Computer does send EDIS-6 "load" calculations from its throttle sensor, but only while driving not on start up

If there is a No Start you could pull a spark plug and see if its tip is WET with fuel, that would indicate crank sensor is working and computer was getting a timing pulse from EDIS-6 module, so was opening injectors


This is a picture of the whole EDIS-6 spark system: https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRLrt-Z62wt4Kw-k0h93Lgg49rATcjfsglHXA&usqp=CAU
 

WVUxZJLx

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Have a good look at the crank sensor and its tone wheel
Tone wheel looks like a gear, it's on the back of the crank pulley, it has 35 teeth and one missing tooth, so 1 tooth every 10deg(360deg) - 1
The missing tooth "gap" is how the spark/computer tells when engine #1 is at TDC

The sensor is a VR(Variable Reluctance) sensor, its generates its own AC voltage as the metal teeth pass by it
This sensor is connected to the EDIS-6 module directly

Make sure tone wheel is spinning true, have someone crank the engine over while you watch it, no wobbling
Check that the crank sensor is not touching the tone wheel should be a small gap between sensor and teeth
Check that the "gap" in not full of mud/dirt
Change sensor if you want, $20-$30, check its wiring back to EDIS-6, 2 wires with a shield wire

EDIS-6 module is connected directly to the Coil Pack
So engine computer is not involved in spark directly, EDIS-6 runs the spark system

EDIS-6 does send the computer the crank sensor's timing pulse(gap) so computer can time injectors
Computer does send EDIS-6 "load" calculations from its throttle sensor, but only while driving not on start up

If there is a No Start you could pull a spark plug and see if its tip is WET with fuel, that would indicate crank sensor is working and computer was getting a timing pulse from EDIS-6 module, so was opening injectors


This is a picture of the whole EDIS-6 spark system: https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRLrt-Z62wt4Kw-k0h93Lgg49rATcjfsglHXA&usqp=CAU
Have replaced the crank sensor and checked it and tone wheel. Plugs are wet. Going to check out that edis module wherever the guy mounted it to. Thanks
 

RonD

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Usually on the rad support front side or back side, it runs HOT, so needs air

Should have 12v with key on, EDIS-6 and coil pack share the same 12v wire

Diagram here: http://megasquirt.free.fr/sources/MS/manual/ms2/edis6ew.gif

The 25uF capacitor on the coil pack is the radio noise suppressor, that small tube with 1 wire, it needs to be grounded, but wouldn't cause no spark if its not, just noise on AM radio stations, lol


Only time I have read about an EDIS-6 module not working was when it was removed from a vehicle with front end damage, it was on the front of rad support and was damaged in the collision I would guess
 

WVUxZJLx

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Have a good look at the crank sensor and its tone wheel
Tone wheel looks like a gear, it's on the back of the crank pulley, it has 35 teeth and one missing tooth, so 1 tooth every 10deg(360deg) - 1
The missing tooth "gap" is how the spark/computer tells when engine #1 is at TDC

The sensor is a VR(Variable Reluctance) sensor, its generates its own AC voltage as the metal teeth pass by it
This sensor is connected to the EDIS-6 module directly

Make sure tone wheel is spinning true, have someone crank the engine over while you watch it, no wobbling
Check that the crank sensor is not touching the tone wheel should be a small gap between sensor and teeth
Check that the "gap" in not full of mud/dirt
Change sensor if you want, $20-$30, check its wiring back to EDIS-6, 2 wires with a shield wire

EDIS-6 module is connected directly to the Coil Pack
So engine computer is not involved in spark directly, EDIS-6 runs the spark system

EDIS-6 does send the computer the crank sensor's timing pulse(gap) so computer can time injectors
Computer does send EDIS-6 "load" calculations from its throttle sensor, but only while driving not on start up

If there is a No Start you could pull a spark plug and see if its tip is WET with fuel, that would indicate crank sensor is working and computer was getting a timing pulse from EDIS-6 module, so was opening injectors


This is a picture of the whole EDIS-6 spark system: https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRLrt-Z62wt4Kw-k0h93Lgg49rATcjfsglHXA&usqp=CAU
Have replaced the crank sensor and checked it and tone wheel. Plugs are wet. Going to check out that edis module wherever the guy mounted it to. Thanks
When they did they swap they bypassed the edis. I do not have one. Convinced now it is still an ignition problem. The only way it will start is if the key is just barely turned to crank but still finikey
 

RonD

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You can't "by-pass" spark systems

So you must have a 1995-2000 4.0l with computer and wiring system
Its OBD2 so should have an OBD2 plug-in for a code reader, would be good to see if any codes are set

The Engine Computer(PCM) runs both the spark and fuel systems, in 1995 and up Rangers
 

WVUxZJLx

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That’s what I figured but I can’t locate the port. I’ve been in every inch of the car. Would anyone know more about the ignition problems. I see online there was a lot of problems with the 🍵 ignitions of those years, but I’ve replaced the ignition tumbler and column section. With messing with the key and trying to start right when it starts cranking I can get it like 50% of the time but sometimes I’ll end up trying until I crank it dead.
 

RonD

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Ignition switch, under the steering column, would split causing it to fail, many repaired it with zap straps(zip ties, ect....), to hold it together

1995, and up, computers were located in engine bay, upper firewall, so the engine wiring harness from computer is fairly limited for its new location
Where did they mount the computer?

If possible get the part number from computer's label, that will tell you the Year of the computer
XXXX-12A650-XX
First two XX's is the year
F5 = 1995
F6 = 1996
F7= 1997
F8 = 1998
3rd X should be 7 for Ranger

Ford changed things in 1999, first digit is the year
X = 1999
Y = 2000
1 = 2001
2nd and 3rd digit
L5= Ranger
 

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