Ford FG F6 - Miss

Hi All,

Have spent much time reviewing other topics on this forum and many youtube vids learning how to utilise a Picoscope, so a big thanks to scannerdanner for the content so far.
Any assistance you could provide with my issue would be great.
Apologies in advance for the long read but hope it helps without being too long, if you require anything else specific please just ask.

Car: Ford FG F6 (aka: Ford Falcon FG XR6 Turbo) Barra 4.0L Turbo.

Current Issue: Intermittent misfires, more noticeable under light throttle/vacuum, uses more fuel than i think it should, appears to run too lean/rich at times.

History: Issue started too long ago to remember exact details, but below has been resolved during this time, wont explain all the details but just summarise.
P0420 - Cat efficiency code raised. From what i can determine, this was caused due to a blocked fuel return line.
The Cat was replaced, later down the track i also replaced the exhaust manifold as i believe the manifold/turbo exhaust housing was warped a little from the restriction/heat build up from the cat. Further down the track i identified the blocked fuel return line and this is also resolved.
Two other DTC's have been raised during the above, most recent was the P1131, Lack of o2 switching, at some stage i also received P0174 or similar regarding o2 reading too rich/or lean.

Worth mentioning that i have taken the car too 3 workshops each a couple of times for assistance, everything mechanical has been tested as far as i am aware and i have gone over alot of things myself, checking for a slipped tooth on timing chain, comp test, leak down test etc...I even made my own smoke machine to test for any leaks lol.

My thoughts and where im at, I believe it may be fuel related, I do have an aftermarket AFR gauge and on a rare occasion I stop at a set of lights, the AFR gauge goes down to 10 and car starts running rough, monitoring the PCM at the same time, it still appears to be in closed loop. On another occasion, it went full lean and nearly stalled, on both occasions it appears to correct itself and read between 14-14.8 again.
During the above, the only thing i could see the PCM was doing was decreasing/increasing STFT obviously to correct the rich/lean condition it was reading. Fuel trims do seem normal at idle, although under acceleration it appears to demand more fuel with LTFT up to say 10 and STFT anywhere from 8 to 15% at times, but then normalises. From what i have monitored on the PCM, I get both soft and hard misses.
Soft misses I can feel the car miss, same with the hard miss, but i also see the misfire count increase, although i have little faith in the logging of it. Cylinder 1 isn't available, Cylinder 4 seems to count at a decimal point rather than a whole number (using livelink SCT), Cylinder 3,5 & 6 seem to have the most misfires. Having the Aircon on, seems to hide the issue a little more.

So, onto my scope question, I have included a trace of Injector current from the feed line and Injector 1 control wire voltage.
It appears that there are additional injector firings when i don't believe there should be.
Engine firing order is 1, 6, 3, 5, 2, 4.
Looking at the attached, you can see the blue trace (Inj current), you can see the smaller current draws between the higher ones, included in this image is the red trace, Injector 1 control wire, you can see where the current draw occurs just after firing the injector appears to fire twice.
Is this normal? PS, I have monitored Injector 2 also and see the same pattern on occasion.



Thanks all,
Michael

Hey Michael!

Definitely an issue with your injector patterns, I'd love to take a closer look. Would you mind e-mailing it to me? wrenchturnsyou@gmail.com

Hi Tyler, have emailed as requested, thanks for your interest.

Just to add further info to this in case anyone is interested.

I have scoped the CMP and CKP sensors, all appears normal with them as far as i could tell. Unsure if im on the right track, but thinking if the injectors were being commanded to fire by the PCM that i may be able to see something wrong with one of these sensor waveforms.
A while ago i noticed there appears to be small puddles of fuel sitting in the intake runners, not much...but i can only think that this is happening due to the intake valve being closed if the injector is fired when it shouldn't be just as the waveform i posted indicates.

Last night while looking through the waveforms i have taken, i come across the below.
Red trace is injector 1 voltage and blue trace is Coil feed amps.
There are a few additional injector fires here, worth mentioning they are the same through the whole trace, coincidence, or not im unsure.
But if reading the firing correctly, Inj 1 fires, followed by Coil 1, next Injector 6 would fire (which we cant see obviously as its not included), but when Coil 6 fires, either an injector (or in this case as shown) injector 1 has been fired again.

Wondering...if i were too scope say Injector 2 with Coil amps that i may see a similar pattern where the injector is firing exactly when another cylinders Coil is.

Got your capture, sir, thank you very much! This capture is B-A-N-A-N-A-S. :lol:

A quick screenshot for anyone following along:



The random injector ramps show up in between all the 'normal' ramps at various times, but seem to most commonly show up between the #6 and #3 injector firings, and the #4 and #1. :huh:

We don't get the turbo 4.0L here in the States, so help me out - Is this a waste spark system? COP? Also, where are the CKP and CMP's located on this engine?

That coil capture is excellent, BTW. The fact that we don't see any random coil firings suggests to me that the CKP is working perfectly, and that our problem may lie with the CMP? That's my theory right now, anyway. :lol:

Hi Mate,

thanks.
You guys do not know what your missing in the states, well, as long as the engine isn't function how mine currently is

Engine is an inline 6 cylinder, DOHC VCT.
This is a COP system. The CKP is located near the front of the engine near the harmonic balancer.
There are 2x CMP sensors located at the rear of the engine, one intake, one exhaust.
I was thinking possibly CMP also, looking at the waveform, nothing stood out to me, but im not an expert.
See included Intake & Exhaust CMP's.

I actually have the motocraft service manual for this car, so can basically look up everything i need to.
I have had a quick visual look at the coil & injector feed/control wires, but not a detailed look by unwrapping the electrical tape etc...from them. The wiring comes in from the rear of the engine rocker cover, all these wires are taped together and as they run up the rocker cover to the front of the engine, each Coil/Injector connector separates out of the wrapping. Thinking it may be worth taking a more detailed look into this.

Unsure if there is an issue with the site, topic shows 17 replies but i dont see them.

Anyway, given the situation and what the scope is showing, im thinking that this may be some wires toutching in the harness or possibly a pcm issue, but would suspect if it were the pcm maybe it would impact all injectors equally, which doesnt seem to be the case.
Looked at inj 2 and inj 3 quickly last night, during this time inj 2 was impacted by additional firing fairly often when the next cylinder fires, but inj 3 not so much, only once did i see an additional fire. Think i might start by doing continuity tests and see if any wires are suspect

That looks crazy. You'd think if it were just coil wires touching it'd at least be firing in time with an incorrect cylinder. Are the wave forms the cam signals? How's the crank look? It's not a cracked tone ring on the balancer is it?

yeah, thats what i figured, but im willing to consider anything a possibility at this stage.

Yep thats intake and exhaust cam sensors.

Below is the ckp sensor (main and sub), looks ok to me, but im not sure on the voltage.



Performed another scope below, injector 2 control wire and Coil 2 control wire.
Appears that the additional injector firing is occurring on ignition for that particular cylinder.
As an example, when Injector 6 (hiccups), Injector fires normally, then as the Coil fires the injector fires again.
Believe the secondary fire on time is less than 1ms, to be honest it all seems to be a little too well controlled, aside from happening when it feels like it. i tested the wiring harness for opens/shorts, didn't find anything worth noting here.

I don't have any help for you here. I'm just curious what codes this has just random missfire code? Does it have rich codes for the extra fuel going in from extra injector firings? What do fuel trims look like? I'd love to know what's causing this if I was going to guess I would guess it's an ecm issue based on all the timing inputs look normal but that's just a guess can't wait to find out what it ends up being

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I just reread your op and see most of my questions were answered In there. After looking at your captures again I'm almost convinced that your scope is picking up small amount of current from the coil on your injector hookup I assume your using an amp clamp ? Can you move from control wire to common power (or ground if that's what they use ) and watch all 6 injectors at 1 time and see if you still have what I believe to be ghost spikes

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Hi ben,

Few different scope images here.
The first one is the amp clamp on the injector supply wire using a fuse breakout , this shows all the 6 injectors, the 2nd channel is hooked up to the pcm control wire for injector 1 only. These are ground side switched by the pcm

Hmm yes I see that in your first capture now I guess I didn't pay enough attention to your op sorry. hmm wow that is the weirdest thing I've seen it just seems since the amperage is less on the 2nd fire that it would have been a amp clamp interference problem but I guess that thought crossed my mind and I ran with it.... anyways I'm back to believing it's a failing driver issue

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All,

Just adding some further comments here.

While the injector firing seems to be random, from what i can tell the correlating COIL firing appears to show a pattern.
So just to note, all injectors do appear to fire a second time, but thus far this appears random, although does show on more injectors than others.
As an example, i believe i included one of the scope pics which showed Injector X fired the second time at the same point that Coil X seemed to fire.

After scoping each coil and Injector, below is what it looks like.

Engine firing order is 1-6-3-5-2-4
Secondary Inj firing:: 2-4-1-6-3-5

Hopefully i have explained the above well enough.
So when the additional injector firing occurs on say Injector 5, it always occurs when coil 6 is firing.
Again, when the additional injector firing occurs on say Injector 1, it always occurs when coil 2 is firing.

Welcome any thoughts, as you can see this all appears too well timed.

What's odd about this is the amperage spike is smaller. hmm ok everything about this is odd but anyways there's a reason that this amperage is less theory 1 is its not the injector were seeing make that second firing but something else on the circuit maybe not seen . You may have tested the control wire of injector and ruled that out already and confirmed it was definitely a injector fire which I don't remember now it's been some time since I read it all . But if that's not it then the ECM isn't allowing enough current out for current to ramp high enough to fully fire the injector in which case I would suspect the ECM is faulty . But I would do a voltage drop test to all powers and grounds to the ECM .

Hi Guys, thanks for all the feedback thus far.

I believe i have an idea of where the cause of the symptoms I'm experiencing.

As noted in previous posts, i see additional injector pulses which i believe are the cause of my erratic fuel trims, lean/rich situations etc...Looking for a reason as to why the car would be doing this, generally one would think that this is not by design on newer cars compared to older cars. Things like group firing injectors come to mind.
A couple of days ago i decided to check for the adhoc additional injector pulses again, to my surprise there were none within the first few minutes, e.g. 2min. The pulses then started to appear again as previously seen.

What was the difference between this test and others i have performed?
The car was stone cold, sitting overnight, i didn't even more it into the garage as i usually do.

Thinking to myself, why were the pulses not there for the first few minutes. Again, possibly an electrical issue such as the PCM which is what i have primarily been trying to track down as the possible issue. I thought to myself, maybe the PCM isn't the issue so to say, but the intentional cause of the additional pulses for a reason, what reason could that be?

Deciding to re-read the PCM service manual section to understand how the PCM operates and what sensors it utilities for feedback under particular circumstances trying to identify why i didn't see the issue for the first few minutes. Upon reviewing the modes and strategy, it appears that when in RUN mode the PCM will provide AE (acceleration enrichment) by providing additional injector pulses increasing injection frequency. This is very helpful information. AE is initiated when the PCM receives what it believes it a rapid throttle opening by driver demand.

So where i will be looking at next is the APP sensor & wiring and wiring to the throttle body. Will post results for future reference, hopefully this information may help others.

PS. If anyone knows what voltages should be seen at APP1 and APP2 signals i would love to know, unfortunately the Ford service manual for me only states the TPS1 and TPS2 signals, so i think they did a copy/paste without updating the information.
Looking at the PCM PIDS using forscan i see the voltages listed at idle as approx 0.38 and 0.70, so believe they are both rising voltages. You guys in the states may have similar APPs that i could use as a reference at least.

VTEAZR wrote: PS. If anyone knows what voltages should be seen at APP1 and APP2 signals i would love to know, unfortunately the Ford service manual for me only states the TPS1 and TPS2 signals, so i think they did a copy/paste without updating the information.
Looking at the PCM PIDS using forscan i see the voltages listed at idle as approx 0.38 and 0.70, so believe they are both rising voltages. You guys in the states may have similar APPs that i could use as a reference at least.

I'm happy to look through my captures! Can you think of a North American analog for the FG? :huh: 'Cause we don't get the 4.0L turbo here in the states (or any of the other cool engines ).

If I see any Ford drive-by-wire systems coming through the shop, I'll grab some TPS/APP data.

Hi guys, hope all is well.
I have not really had any time to try anything else on this, except for tonight.

So i hooked up my amp prob to the inj 1 control wire.
Hard to do this while driving myself obviously, but this is basically what i found.

During decel - open loop, the normal and adhoc injector firings disappear, as one would expect i guess. This indicates to me that the adhoc firings i see are coming via the control wire, otherwise i should still see them i would think.

During idle - closed loop, as expected, i see the normal and adhoc injector fires. Although i did felt i see them more often when in drive vs park or neutral. Also, if i just touched the accel with my foot on the brake while stopped, again i felt i had seen less of the adhocs.

During driving/cruising - closed loop, i still see the normal and adhoc injector firings.

During driving/hard accel, which should be open loop/wot, i still see the normal and adhoc injector firings. To be sure on this one i would need to connect my scanner and retest while running the scope.

Welcome any thoughts as always.
Cheers,
Michael