Sorry I know this topic has been beaten to a pulp. I couldn’t find another thread quite like I’m facing.

Im working on an 04 Ranger 4.0 SOHC

I’m not getting spark to my coil. I have 12v at power wire on coil main plug but the 3 ground wires are not pulsing ground. They just stay constantly grounded.

New crank sensor with around .575AC to PCM. All 3 ground wires from coil main plug have continuity to PCM.

Battery in good condition and fully charged.

All fuses are in working order.

I tested compression on cylinders 1,4 and 5.
cylinders 4&5 are at 170 and 1 is around 155-160.

Did a 50/50 test just because and no change.

High end scan tool didn’t detect any codes and all modules appear to be working fine.

It’s worth noting the pickup was running/driving before tearing down to do head gaskets and timing replacement.

Does anyone have any suggestions as to what I might be missing? I’m open to try anything within my capabilities.

 

Also I should probably mention it does crank over. And the check engine light comes on when key is in RUN position and goes off while cranking.

Plugs have fuel on them after cranking as well.

PATS light flashes every 3 seconds or so until key is inserted and goes out.

 

Welcome to the forum

Good testing


Unfortunately you are down to a failed PCM(computer) or very weird wire failure, i.e. engine would fire even if 2 of the coil packs 3 ground wires were damaged
The 3 ground wires on coil pack run back to PCM
Pins 26, 52 and 78 on 104-wire connector run to the coil pack, same wire colors matching coil pack wire colors
Pull that connector off PCM and test those wires, they do share a common connector on their way to the coil pack, the large square connector on engine, so "possible" failure point for all 3 wires, but very weird, lol

Also test pins 24, 51, 76, 77 and 103 for GOOD Grounding
PCM doesn't share Grounds internally, so one bad ground could only effect one system, like spark, again very weird, but possible

Pull out the PCM and get the part number off the label
it will start with 4L5Z-12A650-xxx

Its last 2 or 3 digits are important, thats the software revision

Go to https://www.car-part.com/

2004
Ford Ranger
Part you want is "Computer box engine"
your zipcode
Search

It will then ask for specific vehicle info and show possible part numbers

PROBLEM you will have is that your Instrument cluster and current PCM are a Matched pair
Instrument cluster is digital and has PATS inside, also Odometer memory(2004 and up Rangers have this)
So when vehicle is made the Cluster and PCM are "matched/married", so people can't swap in lower mile odometer or swap out PCM to avoid PATS, no start

There is a software called Forscan, and a forum for it, I would see if anyone has been able to "re-marry" Cluster and PCM using this software
It is a good software, like an OBD2 reader on steroids, lol, it can do alot of stuff and not expensive
Do need an OBD2 to USB cable to access vehicle electronics from laptop or tablet

Ford Dealer can of course "re-marry" these but they will be more expensive and may not do it if they are not supplying the new PCM, because they don't want to hassle with it if a problem arises using YOUR parts

Other option
Get PCM and Cluster from same vehicle, they will already be a Matched Pair
But.............PATS keys in new clusters memory will be different
Forscan can for sure reprogram your current keys(need at least 2) to the new Cluster/PCM combo

 

Thanks for the reply. I will try all you stated and see if that gets me anywhere. Bad PCM is about one of the last things I want to be the issue here due to having to replace all that goes along with it and the cost involved.

I did test coil plug ground wires for continuity back to PCM and it seems to be fine. I’ll double check that and the square plug for any issues. If I am correct you are saying the coil plug wires run from coil to square plug then back to PCM? I did notice on the square plug, one of the corner connection prong looked to be missing. Not sure if that is relevant or perhaps there never was a prong in that slot, I’ll look to see if any wiring is running to that pin.

I have yet to test the ground wires on PCM plug and will do that when I get back home and relay the results. I’m really hoping that’s my issue.

My battery was unplugged and removed first thing before starting on removing anything else. It’s quite possible the PCM failed but just seems unlikely. The pickup ran the day I started disassembly. Also may be of irrelevance but pickup sat for a couple months before I bought it and found a huge rats nest under the intake, it wouldn’t be a stretch to say they may have been gnawing on some wiring and the flexing of the wire harness could have just been the final straw for 1 or more wires.

Again I truly appreciate you taking the time to answer another no spark issue.

 

Okay so I checked all grounds listed in PCM plug and all check out with good ground.

Went over to coil plug and checked for continuity to PCM and all 3 are good as well. I assume the square plug in between is fine too as I’m still getting good contact and it’s between coil plug and PCM. I also looked at square plug and the pin with no contracts does NOT have a wire running through it anyway hence no contacts.

Key on and all 3 ground wires have a solid ground. With the coil plug (unplugged from coil) I do not have ground to either ground wires. However I can get 12v to the power wire with connector unplugged/plugged in.

Now here’s the weird thing… at least to me. I have power to the 3 ground wires with key off. I was using a test light to battery positive and back probing each ground wire and it was lighting up my test light. When you turn to on position the power is cut. My test light does not blink or show any sign of power while cranking on either wire. Maybe the change from power/ground it too quick for the light to react.

Could I possibly have a bad crank sensor even though I have around .575ACV to the PCM plug and at crank sensor connection? Also my check engine light appears when key in RUN position and goes out while cranking.

Is it possible to get a reading from crank sensor even if there is an issue between harmonic balancer and crank sensor? I’m not totally sure if crank sensor is picking up TDC from the tone wheel, making it so I don’t have a pulse to grounds at coil. Tone wheel is in good shape, I just bring it up because I did replace timing components including crank gear. Could it be a possibility the new crank gear is either thinner/thicker than OEM causing balancer to sit too close or too far from block and not letting crank sensor to pickup TDC?
I know that’s a long shot but I want to eliminate all possibilities.

Im dancing around the idea of a new PCM because I know it’s going to cost me an arm and a leg. I live in a very rural area and the closest parts yard is over 100 miles away. The very last thing I want to do is take it to Ford so they can throw thousands of $ out of my wallet at it, but I’m running out of options here and it’s going to end up at ford in the end anyway if I have to have them reprogram PATS.

Sorry for the rant, I just want to get you as much info as I possibly can.

 

The CEL goes off when cranking IF the Computer "sees" a good timing signal from Crank sensor, so that is not the issue, and you said spark plug tips were WET after cranking so computer IS opening injectors for startup


An ignition coil sparks when power is cut, after being on, all 3 coils should get 12v and be grounded with key on, the 3 wires can be grounded with key off, i.e. your test, thats fine

Test light hooked to battery positive and one of the coil packs ground wires should flicker when cranking as computer cuts and restores the ground to spark that coil, you would see it for sure

Long shot
There MIGHT BE a radio noise suppressor, usually bolted to one of the coil pack bolts, 1 wire, follow that wire and UNPLUG IT, its plugged into the 12v coil pack wire, its a condenser, it may be lowering the voltage on coil pack, without blowing a fuse, extreme long shot

 

Okay so crank sensor is ruled out.

I did unplug the grey rectangular connector bolted to coil ground mount that I believe is the radio silencer, however I did not follow to wire further back to disconnect so I’ll try that.


So I’m left with ground wires to coil not pulsing and why. The only thing I can actually think is something in the PCM is bad so I suppose I’ll have to call ford Monday and have them quote me for that. More than just having to pay an *** load of money to the stealership, it’s on my conscience that I have been defeated by this damn pickup. This will be the first and hopefully the last time I ever have to take my vehicle in to be worked on by someone else.

Thanks again for your time, I appreciate it more than you know. I will report back to this thread when the issue has been resolved.

If at all you do think of something I could try in the meantime I’d love to hear it.

 

PCM uses driver transistors to ground and unground coils, so 3 of them in a V6 PCM
Likely hood of all 3 "blowing" is low, so it would be something else in the software/firmware thats failed
And it would be something that wouldn't set a code

Crank sensor is the most obvious choice, since PCM wouldn't even know you wanted to start engine until it "sees" crank sensor pulse, so wouldn't set a code
Do you have a Tachometer on the cluster and does it move up to 200rpm when cranking, thats another indication that crank sensor is working
OBD2 reader can be used to see if PCM is seeing Crank sensor RPM

Wet tip spark plug
I would pull out any easy to get at spark plug
Dry it off
Put it back in
Crank engine
Pull it out again to see if its tip is WET
If so then PCM is getting RPM pulse from crank sensor
If not you may need to revisit crank sensor and its wiring, although CEL going off when cranking doesn't make sense

Computer Sanity testing
Unplug the crank sensor
Crank over the engine
Check for codes, should be a P03xx code

2004 PCM has Crank sensor and Cam sensor to compare if one or the other is not working or "out of time", Crank sensor is the main one and only one that can cause a No Start

Unplug MAF sensor
Crank engine
Should get a MAF Code

You can do the same with other sensors, one at a time, see if PCM can set correct codes when a sensor is unplugged
Basically you are doing a "leave no stone unturned" test on PCM sanity

 

Did you figure out your issue? Did you replace any of the timing components with Cloyes parts? Which harmonic balancer do you have? The solid machined or the one with the stamped reluctor wheel?

Just an idea because I went through this about a year ago. I diagnosed a failed PCM and replaced it. Pulled my hair out and towed it to a Ford dealer. They diagnosed it with a bad PCM. Guess what no spark with PCM #2... The Cloyes crankshaft sprocket pushes the harmonic balancer with the stamped reluctor wheel out just enough to not get a good pulse. You'll get a injector pulse, tach signal, the CEL will go out, and no spark.

 

TDIRanger, thanks for the reply. I have yet to figure out the issue. I ran through all the tests above and came to the conclusion either it’s a bad PCM or somewhere my wiring isn’t doing it’s job. I decided before taking it to FORD I’d replace the PCM and see if I can get somewhere with that. I did read somewhere that somebody has had an issue with crank sprocket either too thick or too thin due to aftermarket components. I did replace all timing components and unfortunately I cheaped out on the timing kit (ultra-power I believe), wish I would have went with OEM or even Mellings. I had ordered all parts prior to tear down and had no clue what I was getting into with this motor, it’s not something I want to have to do again anytime soon. I did take a couple thin washers and placed them behind the crank sensor to bring it out a touch with no luck. I also took the old crank sensor and shaved some off the backside to try and make it closer to the block and again no dice. I even held the crank sensor and moved it slowly all around the harmonic balancer as I had someone crank the engine over to see if I could get a pop or anything, again no luck there. The harmonic balancer I have has the reluctor wheel and doesn’t appear to be damaged or anything. I had seen on another thread that somebody had “shaved” the reluctor wheel at the missing tooth with success but I have no idea how or where and how much and I really don’t want to have to buy ANOTHER part chasing this damn no spark by ruining the one I have now. Perhaps I’ll have to end up buy a new balancer without the wheel to see if it changes anything if the new PCM doesn’t pan out.

RON, thanks for your reply as well you’re a huge help. I had to step away from this thing before I lit it on fire and pushed it off a cliff. I’ll get out there and pull a few sensors to see if I can get it to pull a code. I DO have RPMs as I’m cranking, I believe the scanner said somewhere around 240. I figured I would buy a new PCM online that has a couple extra keys and is “programmed” to my VIN, whatever that even means LOL. I realize I have to have the new keys cut and more than likely take it into FORD and have them program it to my cluster. They want $175 to program it for me. Ford said I can’t get PCM from them right now either because there is a shortage or something and that he’s seen them going as high as $1200 and there is at least 6 rigs at the shop now waiting for new computer, hence the reason I bought online.

 

Here is a link to my no-spark drama .

https://www.therangerstation.com/for...cement.195658/

Moving the CKP sensor probably should have produced a spark. I don't know. The older style balancer may be worth a try. Good luck

 

Dang I really wish I would have found that thread before ordering a PCM. Thanks for the link and glad you found the issue, sucks when even master techs can’t diagnose correctly and left with nothing but dead ends. I’m not exaggerating when I say I spent 40+ hours looking online through threads and somehow this one escaped me, although I did see a couple similar ones. I have a feeling the issue doesn’t lie with the PCM but we will see here within the next couple weeks.

The crappy part about the new PCM is the company I bought it from wants a 20% restocking fee, $85 if they programmed PCM to your vehicle and a $90 fee for keys they gave you. When you add all that up I would get back a WHOPPING $20 refund if I decided to send it back which obviously isn’t even worth my time. However I suppose they have the “latest” updates and whatnot so maybe I’ll get better gas mileage or some kind of benefit if and when I ever get it on the road.

If I did order another balancer, are there any particular brands you would avoid? I haven’t done too much research on it other than pricing and they’re not the cheapest part out there to say the least.

 

I bought the harmonic balancer from rock auto. I don't remember exactly which one I bought. It was just over $100. If not using OEM, I usually buy the more expensive of whatever aftermarket part so hopefully the quality will be better. This may not be the solution to your problem, but it worked for me.

I have 2 good PCM's I bought. I guess they will go on eBay at some point.

 

I found a balancer on Amazon that’s in middle of the road as far as price goes, I’ll keep that in mind for the next thing I’ll try.

My PCM is due to arrive today and it comes with two new keys. Of course I’ll have to have them cut to the ignition but do the keys themselves need to be programmed? Also would my old key suffice as far as just cranking engine over? I know I won’t have fuel delivery until I get the PCM and cluster married but I should have spark correct? And if I do not have spark I can assume the PCM wasn’t the issue and I don’t need to prioritize getting the pickup into Ford, and in the meantime can put old PCM back in temporarily and focus on the next step.

 

Well I got the PCM and keys. I had the keys cut and and new PCM installed. Turns out I didn’t have to take it to Ford to get programmed to my cluster, as the company selling computer must have already handled that. I believe this because my fuel pump is kicking on and PATS light goes out when key on.

However, the computer didn’t fix my problem. I still have no spark… I suppose my next step is to replace the harmonic balancer. If that doesn’t do the trick Im really at a total dead end. I’ve already sank far more money that I intended on this thing and I REALLY don’t want to take it in for diagnosis as I am highly doubtful they will be able to track down the issue.

I’ll keep in touch after I put a new balancer on it and check in here periodically to see if anyone chimes in.

 

I just wanted to check back in and give an update, I can’t stand when people ghost a thread after they found a fix to their issue.

The issue with no spark was in fact the harmonic balancer. For whatever reason it wasn’t reading TDC on the original. When I pulled original off and compared to replacement balancer they both looked to be equal as far as the keyway slot and the missing tooth, however the original balancers reluctor wheel could possibly be off by a very minute amount or perhaps there was another reason it wasn't reading but I couldn’t tell a difference. I went with the stamped balancer instead of the original style with the reluctor wheel for a replacement.