'92 Explorer 4.0L NO SPARK

[Mylesofsmyles]

I'm at the beginning of my learning curve again, with a new ford...

It's a '92 4.0L Explorer...This is a distributor less EDIS ignition

NO SPARK...

swapped for a known good CPS...no luck
swpped for a known EDIS ICM...no luck

What should I do next?

 

[RonD]

There are CPS(cam position sensors) and CKP(crank position) sensors, those are my names for them, just so I can talk about them without confusing myself, lol.

I don't think the '92 4.0l had a CPS, but it could have, it would be in the never used "distributor hole" at the back of the block top side.
CPS isn't used for basic spark timing.

Ford EDIS system is self contained spark system, it has 3 parts:
CKP(crank position) sensor
EDIS-6 module(for V6)
Coil pack

CKP sensor wires run to EDIS module
Coil pack wires run to EDIS module

EDIS module and Coil are both powered by the ECU(EEC) relay found in the Power box in engine bay.
Just check coil for 12v with key on
Coil has 4 wires, Red one is the 12v

EDIS module pins are here: http://www.dainst.com/info/edis/edis.html
Toward the bottom

VRS(variable reluctance sensor) = CKP sensor

The way it works is that the CKP sensor will generate an AC Voltage as the "teeth" on the crank wheel spin passed it, there is a missing tooth or wider tooth on the wheel that denotes #1 TDC.
This pulse tells EDIS module to start the spark, so it all starts with the CKP sensor pulse, no pulse = no spark.

If you hook up a volt meter to the CKP sensor and crank engine you should see about .5 to 1v AC
i.e. if you unhook the EDIS wires from the module and test the VRS+ and VRS- wires with volt meter you should see the AC voltage while engine is turning over, this would test the sensor and wires to sensor

EDIS module sees the pulse and starts timing for spark, #1 TDC being the starting point.
The EDIS module passes this #1 TDC info to computer along with RPMs(from CKP sensor)
Computer uses that info to time the fuel injectors, and starts them about the same time as the spark.
If you crank the engine and then pull a spark plug out and it is wet, then CKP sensor and EDIS timing signal is getting to the computer.
If spark plug is dry then either gas tank is empty, lol, or computer is not getting a timing signal from EDIS module.

Google: How to test ignition coil pack the easy way

There is a short video on how to test for a bad coil, although I wouldn't think all 3 coils in your coil pack could fail at the same time.
So either coil doesn't have 12volts or EDIS module isn't grounding it(firing it)

 

[Mylesofsmyles]

Thanks...that's a great write-up...

I'll take a closer look.

Smells of gas after cranking, so I think fuel system is doing it's thing.

 

[Mylesofsmyles]

Just wondering....

On my '85 Ranger, the TFI module needs 12v while cranking. The exciter wire to the starter splices with a lead to the TFI module on my distributor.

Currently, with this 4.0L, I have a dead starter relay...so were jumping it there...Since there isn't 12v at the exciter wire from ignition switch, do you think I'm not getting power to the ignition system while cranking?

 

[Mylesofsmyles]

^ scratch that idea...just experimented with another running 4.0L we have here...put key in run and jumped the starter relay...my theory didn't work...it'll still start.

 

[RonD]

Fords have a Clutch switch on manuals and an NSS(neutral safety switch) on automatics.

These have to be "closed" for the 12volts to go from ignition switch to starter relay

Clutch switch is clamped onto the master cylinder push rod, clutch pedal has to be push down to the floor to "close" this switch, while not common they can pop off, they are held on the rod by a slide clip.

NSS is on the transmission just above shift linkage, the column shifter on Ford trucks gets loose so when shifted into Park trans does go into Park but doesn't push up enough on NSS so you get a no crank, try Neutral to see if that's the problem.

 

[Mylesofsmyles]

Interesting

 

[AllanD]

Fords have a Clutch switch on manuals and an NSS(neutral safety switch) on automatics.

These have to be "closed" for the 12volts to go from ignition switch to starter relay

Clutch switch is clamped onto the master cylinder push rod, clutch pedal has to be push down to the floor to "close" this switch, while not
NSS is on the transmission just above shift linkage, the column shifter on Ford trucks gets loose so when shifted into Park trans does go into Park but doesn't push up enough on NSS so you get a no crank, try Neutral to see if that's the problem.

The NSS switch on manual transmission RBVs (and some other fords) has NOTHING what-so-ever to do with cranking, starting or the ignition system

The NSS switch is all about idle strategy with the engine NOT under load

There is also a contact in the clutch multifunction switch that performs a parallel function, but in any case 1993 was the last year the NSS switch was actually installed on any RBV manual trans, on 1994's they didn't even drill out the hole where the switch would be mounted to the transmission

The worst the switch being disconnected will do is cause your engine to stall when rolling up to a traffic light, this gets deeper into idle strategy, because when engine braking above a certain RPM (Different for each engine) the fuel injectors are turned OFF To both reduce emissions and increase engine braking effectiveness.

AD

 

[Roe Automotive]

Im way late to the party here but I found some very helpful information on this thread and would like to share my findings in case anyone else reading this needs just one more thing to check, I had a 92 ranger 4.0 come in for a no start at times, it had the electronic distributorless ignition system on it, sometimes it would crank and run beautifully other times it would spark once from the coil upon initial cranking and spark once when you let off the starter, i wound up getting my butt kicked by this problem, I started by testing the crank sensor which the customer had replaced, it would generate ac voltage when reading the vrs signals at the edis module unplugged, the edis module would generate the profile ignition pickup and the computer would send the spark angle word back to the edis module when the engine was running, when it would not run i had no pip signal and no saw signal, but the crank sensor was generating a signal to the edis module which confused the crap out of me, i had thoroughly checked the powers and grounds to the module in run and crank and all was well, also checked the wiring from crank sensor to edis module, I wound up finding the factory original crank sensor in the floorboard of the truck and shaved the locating tab off the back and then slotted the two mounting holes and shimmed the crank sensor.030 from the reluctor wheel, this fixed the problem, the module sent the pip signal everytime. So if anybody is chasing this problem with a master-pro or cheap aftermarket crank sensor, be warned. I ordered a better aftermarket replacement and fixed the truck. Gotta K.I.S.S.

 

[Shran]

Im way late to the party here but I found some very helpful information on this thread and would like to share my findings in case anyone else reading this needs just one more thing to check, I had a 92 ranger 4.0 come in for a no start at times, it had the electronic distributorless ignition system on it, sometimes it would crank and run beautifully other times it would spark once from the coil upon initial cranking and spark once when you let off the starter, i wound up getting my butt kicked by this problem, I started by testing the crank sensor which the customer had replaced, it would generate ac voltage when reading the vrs signals at the edis module unplugged, the edis module would generate the profile ignition pickup and the computer would send the spark angle word back to the edis module when the engine was running, when it would not run i had no pip signal and no saw signal, but the crank sensor was generating a signal to the edis module which confused the crap out of me, i had thoroughly checked the powers and grounds to the module in run and crank and all was well, also checked the wiring from crank sensor to edis module, I wound up finding the factory original crank sensor in the floorboard of the truck and shaved the locating tab off the back and then slotted the two mounting holes and shimmed the crank sensor.030 from the reluctor wheel, this fixed the problem, the module sent the pip signal everytime. So if anybody is chasing this problem with a master-pro or cheap aftermarket crank sensor, be warned. I ordered a better aftermarket replacement and fixed the truck. Gotta K.I.S.S.

Good info. So the original crank sensor was dead and the aftermarket one was mounted too closely to function if I am understanding correctly?

Always good to have feedback like this!

 

[Roe Automotive]

Good info. So the original crank sensor was dead and the aftermarket one was mounted too closely to function if I am understanding correctly?

Always good to have feedback like this!

Well the original crank sensor was dead until I moved it closer to the relutor wheel. The magnet on it was weak and moving it closer regained the signal. The other two cheap after market sensors generated a different signal from the original. I caught that when measuring ac voltage at the crank sensor spinning the engine over i got different reading from factory sensor, also when looking at it on a labscope a similar but different signal. The whole ironic part is the vehicle was towed here from another shop who had installed a crank sensor, they were technically right but the cheap aftermarket sensor bit them in the butt, haha after a complete wasted day my aftermarket sensor also bit me in the butt.