Fiesta 2003 1.3 Misfire on Cyl#1

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Fiesta 2003 1.3 Misfire on Cyl#1

Postby FioranoCars » Sun Jul 30, 2017 7:30 pm

Hi all, penance time for posting Friday off-topic rubbish (more answers and catch phrases still needed though! :D )

Anyway, there is a point for discussion within this tale, so feel free to skip to the end and then jump in with your thoughts ...

I was at the MOT station and one of their apprentices was struggling on a Fiesta, and asked me how to/help to confirm compression on cylinder 1 (he knows me and has had a bit of help before!), and yes i did ask why etc, he had checked spark already and it was "good" and had physically pulled the injector rail off and all were firing fuel!! :roll: :roll:

The car is a 2003 Fiesta chassis WF0DXXGAJD3E84924, which I think is a 1.3 (1299cc) BAJA engine code, firing order 1-3-4-2, but as 2 databases have conflicting data, one showing it as a 1.4 (1388cc FXJA?) and the other as 1299cc I'm not sure, and I did not look at the gear stick, so took the first database statement of Automatic at face value along with Mk5, but not so sure ... think it is a Mk6 and manual now but anyway the only thing that really matters is the firing order and they are the same for all of the range, so for the purpose of discussion it's not critical, but anyone who can confirm the spec from the chassis please let me know so I can get the waveform library correctly updated and tagged...

I was only passing through with an MOT, not being paid for helping, just had the scope & kit with me for another reason, but did not want to leave the poor chap without help, so I had 45mins to spare while waiting for the MOT, so out comes the scope ...

Rather than check everything, I thought I'd humour the situation and did a Quick & Dirty amp clamp only relative compression test. If any single cylinder was low, we'd then sync and put in a pressure transducer to look harder, but first was Q&D prove if we were going the right way ... result below (all the files are in the waveform library - or will be, the only auto fiesta there):
Channel B = Amp Clamp
relative compression.png
Good balanced compression using amp clamp

Clearly no single massive issue, all within 3-4% of each other and no rotational speed variation ... so back to basics....

Started to ask the questions, what did the car come in for, what was the symptoms etc ... Answer: MIL on, codes cleared but were for Cyl#1, leave it long enough they come back. The misfire was present while we talked.

Based on his proof of fuel (rail off!) and PIDs showing nothing mightily askew (for air flow, throttle, sensors etc) I thought best to prove spark first. Simple coil pack, easy to access HT leads ...

Started on Secondary Ignition for ease, only had 2 Inductive leads plus wand, so sadly can't show you a stack of all 4, sorry, on a time limit!
Channel C = Secondary HT Lead - Cyl#1 > cylinder #1 has no dwell, and a "burn line" if you can call it that? of over 1kv - clearly a bad trace IMHO
Channel D = Secondary HT Lead - Cyl#2 > cylinder #2 has dwell of 4ms+/- burn line at circa 700v peak KV circa 10kv +/-

secondary cyl 1 verse 2.png
Secondary Ignition Cyl#1 verse Cyl#2


This started a conversation about how spark was previously proven as good!! :oops:
It was tested by using a "spare" spark plug and putting each HT lead onto it, then starting the engine and "grounding" the plug to the block, seeing a few "sparks", putting plug down and turning engine off ... repeat 4 times. :twisted: :twisted:
So if the coil was not damaged to start with it was certainly not helped by the lack of consistent grounding during the tests. I pulled out a proper spark tester (enclosed body with adjustable gap), on ebay or Amazon for under £5, so no reason to not have one, even two in the toolbox!

A quick visual test to prove to the trainee how to do it and that the scope is not lying (remember he's still adamant the spark is good!), and cyl1 could not jump even the smallest gap setting, while cyl2 provided a lovely clean spark even at max gap - so he could now see the difference, sadly the spark tester would not drop down to <1mm gap, which is all the spark plug would have proven, which at atmospheric pressure is not proving much at all. Anyway trainee now able to see the issue visually and on the scope so bought into the problem not related to compression and that focus could continue within the "spark domain".

All 4 sparks were then tested using the 2 pickups and the wand, while cylinder 1 was worst, cylinder 4 was not reliable. As they share one half the coil it was not surprising to see this, as once one fails the twin is not far behind.

To prove the leads, moved to the coil for primary checks. It should be noted that the leads had been off and the plugs removed already and not had any visual defects arching/water ingress/etc (not witnessed myself!) ...

We did both primary voltages with Current clamp and added Cyl#4 as paired with Cyl#1 on the coil, but was giving some sign of erratic action rather than almost dead, with more of a spark/waste alternation visible:
Channel A = Primary Ignition Coil 1/4 trigger
Channel B = Primary Ignition Coil 2/3 trigger
Channel C = Primary Ignition Current
Channel D = Secondary HT Lead - Cyl#4
primary pre replacement.png
Primary ignition pre-replacement of coil

Cyl #1 primary does give an impression of some form of spark/burn, which the previous secondary is clearly refuting, worse the current dwell does not correspond to the secondary. Maybe I should check more coils, but not seen that I can recall before? :?: (I assume an internal short in the coil is allowing the dwell/charge but not delivering it to the plug?)

There is a lack of good ringing on all 4 cylinders, but IS this enough on it's own to condemn a coil? Fortunately we had more evidence with the secondary, and a quick resistance check of the HT leads showed no obvious issues. The new Coil arrived PDQ and was fitted (nothing else touched - leads/plugs/cables except to bolt on the coil and swap the leads over).

Retested just before i had to put my kit away and go, but managed to get this:
Channel A = Primary Ignition Coil 1/4 trigger
Channel B = Primary Ignition Coil 2/3 trigger
Channel C = Primary Ignition Current
Channel D = Secondary HT Lead - Cyl#4
Post coil replacement full.png
Overview of post coil results

At a cursory glance all looked good, the error was cleared and car sounded fine, did not wait for the new plugs to be fitted and the adaptive memory to be reset, MOT was done and I needed to get going ...

As far as I know the car left once those things were done without any issues, but as always, I looked at the captures later to file them, and with the thought of doing my bit and uploading them to the waveform libraary, when I noticed a potential issue... which I assume teh car is still displaying!

For a quick look, below is zoomed in to Cyl #4 you can see it's getting full 4ms of dwell and 10amp charge (both for Cyl 1 &4),
Post new coil current primary secondary.png
post Coil replacement Primary/secondary/current

sadly the dwell for 2 &3 is about 20% shorter (3.2ms) and only getting a 6.5amp charge, see below
post coil replacement poor dwell.png
Poor dwell

Notice in all of them good "ringing" BUT this unven dwell and charge can't be a good thing? Not able to go back and test.

So nothing amazing here, no earth shattering things, right?
But a few things to discuss for sure, the devil is in the detail, even the simple tests through up nuances to study ...

1. The old faulty coil has equal current for both pairs, matched dwell times too,
The new coil has varying differences, but at their most extreme at idle 6amps verse 10+amps between pairs, and dwell time drops from 4+ms (1&4) to <3.2ms for the lesser charging pair (2&3) The only thing changed was the coil, took maybe 4mins, leads and plugs the same, bolted down so no earth issue, no codes reset, so not into some self learning cycle ... WHY ? :?: :?: :?:
Anyone able to shed light on this, or is the NEW coil faulty :idea: ? What am I missing?

2. Bosch Training and a few others experts/bodies are recommending NOT to measure voltages on injectors or other high voltage signals (coil and spark clearly fall into that category) even with attenuators ... but I think without the use of volts this would have been a much harder car to correctly diagnose?
a.What do Pico recommend or think about the advise from Bosch (and others) ?
b.Could you have diagnosed this another way without using voltage ?
c. Have I misunderstood that there is some difference between voltages on injectors (GDI/HP Diesel) verse Ignition?

3. I'm concerned about the nuance of noise, when it might be a failure indicator and when it is just noise, is this something that is being seen by others? I've reduced sample rates for all captures by default (never leave setting at 1MS unless I really need that detail) to reduce the incidence (and removing mains power from both the car and the laptop!), but I think that has separate risks for diagnosing ... anyone have different strategies? :idea:

4. Still on noise, I think that without the primary voltage on the faulty coil pack, the current "noise" might be overlooked, as although it's worse on 1 "half/pair" it's present on both to a small extent and on the new coil too, so doubt anyone could honestly say they would call out the coil on that alone? I am wrong? :oops:

5. Would the lack of ringing be enough to confirm the coil as faulty? Does the ringing vary from make/style of pack or should this always be good? :?

I'm really interested to understand this, and have a renewed awareness in needing to give each and every waveform more than a cursory glance to be sure things are good ... rulers help to spot variance, maybe I should use them as routine to avoid this sort of issue, even if I was just "helping" out for free, I think you owe a duty of care no matter what.

I have attached some files, they are on the waveform library, and if you want any of the working files or full size captures then I can share them via the cloud, if anyone is interested?

Best
Richard Lukins
Attachments
Ford_Fiesta_2003_Petrol_Post coil replacement sml.psdata
Post repair Primary and cyl4 secondary
(10.27 MiB) Downloaded 14 times
Ford_Fiesta_2003_Petrol_Primary + cyl#4 secondary - pre replacement of coil sml.psdata
Primary + cyl4 secondary
(24.69 MiB) Downloaded 11 times
Ford_Fiesta_2003_Petrol_Secondary cyl1-2 pre-repair.psdata
Secondary pre-repair
(3.79 MiB) Downloaded 11 times
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Re: Fiesta 2003 1.3 Misfire on Cyl#1

Postby Martinjensen » Mon Jul 31, 2017 9:23 am

From Ford ETIS

Produktion date: 07.04.2003
Fiesta/Fusion 2002
3-Door Sedan
Version: Serie 20
Engine: 1.4L Zetec-S EFI DOHC (75/80PS)
Transmission: Manuel 5-trins transm. - iB55-ASM
Euro IV
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Re: Fiesta 2003 1.3 Misfire on Cyl#1

Postby FioranoCars » Mon Jul 31, 2017 12:32 pm

Hi Martin
Thanks for this,
so 1388cc
For the engine code is it the FXJA or FXJB :?: or does it matter? Not familar with Ford at all !! Sorry! :oops:

Cheers Richard
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Re: Fiesta 2003 1.3 Misfire on Cyl#1

Postby FioranoCars » Mon Jul 31, 2017 1:37 pm

1. The old faulty coil has equal current for both pairs, matched dwell times too,
The new coil has varying differences, but at their most extreme at idle 6amps verse 10+amps between pairs, and dwell time drops from 4+ms (1&4) to <3.2ms for the lesser charging pair (2&3) The only thing changed was the coil, took maybe 4mins, leads and plugs the same, bolted down so no earth issue, no codes reset, so not into some self learning cycle ... WHY ? :?: :?: :?:
Anyone able to shed light on this, or is the NEW coil faulty :idea: ? What am I missing?


The only other reasonable thought I've had about this imbalance (other than potentially faulty coil pack, but not ready to condemn it just yet), is that the ECM self learnt values were influencing the spark timing and it's just still compensating for the 1&4 being weak prior to the repair, and now has enough energy to "back off" 2&3 ... Eventually the self learning would restore balance, or via a self adaptive reset... ? :idea:

Or am I talking complete poo? :oops: Would or could the ECM engage and control a strategy of different sparks in the coil pairs? Is this one step beyond ?

Thanks In Advance
Richard
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Re: Fiesta 2003 1.3 Misfire on Cyl#1

Postby victor2k » Mon Jul 31, 2017 3:02 pm

Hello,
I think I saw on Peugeot/Citroen this coil charging time with different values for cyl 1-4 vs 2-3,but I don't know how ECU make this adaptation.
Ford use this ignition timing system with feedback correction:
http://google.com/patents/EP0390314A2
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Re: Fiesta 2003 1.3 Misfire on Cyl#1

Postby STC » Mon Jul 31, 2017 9:54 pm

Richard

I thought best to prove spark first. Simple coil pack, easy to access HT leads ...


If this is a "Wasted Spark" setup which I think it is then it is unlikely that you can have a Ignition Related single cylinder misfire. Other than one Spark Plug with little or no gap, any other ignition breakdown would affect 2 cylinders, perhaps not equally but it would have measurable effect.

Spark Polarity will influence KV's. A Positive Spark will Require more KV's than a Negative Spark. ( or is it the other way around ?) And these cars are not fitted, at birth, with 4 equal spark plugs. The negatively fired ones are different to the other 2. Lots of issues caused by that alone. If you take the plugs out and look carefully you will see that they erode differently.

The misfire was present while we talked.

In hindsight a look at O2S1, STFT, LTFT. In a MOT station an analysis of all 4 gasses would have given good direction. Now a missed window of opportunity. Or not ??
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Re: Fiesta 2003 1.3 Misfire on Cyl#1

Postby STC » Mon Jul 31, 2017 11:13 pm

2. Bosch Training and a few others experts/bodies are recommending NOT to measure voltages on injectors or other high voltage signals (coil and spark clearly fall into that category)


First and foremost it is due to Liability, Health, Liability, Safety, Liability & Emissions, Not wanting to be on the end of law suit.

The other reason is simple but I cannot tell you or ......... If the Picoscope was encased in a green box then things maybe different, but it is blue, and they are not :D :D

We could have a similar conversation about the Powerprobe offerings.

If you feel that you need to look at voltage and believe that you can gain diagnostic value -Go ahead and do it, Safely !

Attenuate
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Re: Fiesta 2003 1.3 Misfire on Cyl#1

Postby FioranoCars » Mon Jul 31, 2017 11:30 pm

Hi STC
all you say is very true, but I was just band-aid helping. The coil replacement removed the mis-fire, so even if not fully root cause, was a contribution factor (root cause if different i'll never know :oops: )

The single misfire (#1) being worse than it's pair (#4) could be possible due to many internal issues within the coil, it does not always fail both halves equally fully at the same time (there is wiring per cylinder than can short to ground rather than per pair!) wasted is not total commonality.

As I said it was Quick and Dirty!

My bigger concern (lack of knowledge) is the unequal current/dwell for the new coil ...

But all you said is correct, looking at PID's in detail would have been the best approach, but I was "fitting in" to someone else's workflow, trying to show how the previous test for spark was wrong... and replacing the coil might only be rectification of damaged caused to that coil pack, not the root cause of the problem which may return ... who knows!

I was hoping to hear that this is defo a DOA coil or that a reset to self-adaptive would rectify it ... etc ... and that everyone has seen this and it's not discussed as it's such a common and well known thing! :D :D

Your second post, Voltage, yes after discussion with a nice tanned bloke back from his hols this morning, I think that Voltage is ESSENTIAL to diagnose many of these faults and while I'd love to hear differing views, as we can all learn, I don't think the tell-tales will be as clear or conclusive, if there at all. Definately need to be safe, and if in doubt DON'T POKE ... 10:1 and 20:1 and inductive pickups exist for a reason!

I await anyone who can show me from current how the coil could be confidently ID'd as bad ... :shock:

I'll be callibng you tomorrow, as otehr problems persist, one thing left to try then :cry: :cry: !

Best R
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Re: Fiesta 2003 1.3 Misfire on Cyl#1

Postby FioranoCars » Tue Aug 01, 2017 12:07 pm

Been doing a bit of work on dwell for another beast, the Mercedes 1974 450SLC but I'll update that separately later, anyway something that I could/should have considered was the energy of this new coil, which using primary measurement will hopefully allow some further facet to be established, or not if I'm building on quicksand! :oops:

First let go back to Physics:
Energy stored is measured in Joules and is ½ the inductance x the current squared.
This means a reduction in current makes a disproportionate difference to energy (as it’s squared), while proportionally Inductance will not change the relationship, just the actual numbers.

Now I do understand my final AMPS is not total charge, but on a time/current supplied the difference between the two will be more exaggerated, so the figures below are just to illustrate things (or my ignorance :oops: ). In fact I think the real figures would show a 4 times rather than double relationship, but let's stick to the basics to illustrate.

With the coil charges of say 6.5amps verse 9.3amp which gives 42.25 verse 86.49, basically double, and that relationship will remain, regardless of inductance (0.2, 1, 20) - the ENERGY in the COIL is DOUBLE - a bit difference:?:

Looking at the primary trace, see below, all 4 spark burn times are 1.4ms +/- 0.1ms and a burn voltage (primary) of 34-40v (only got no4 secondary but that's 750-1,250v burn line) - Maybe you need to see secondary burn lines, but the duration is not going to change - so this is not showing a DOUBLE sized relationship?
burt times and voltages.png
Burn Times and Voltages VS different Currents


Just to compare the duff coil pack, the better 2 spark lines were circa 40v and just under 1ms duration, the bad 2 were 50v and next to no duration (if you can rely on the messy trace, as #1 was not sparking at all at the plug).

My question is where is this extra energy dissipating to?

Is voltage at sparkline and duration not going to show any correlation with "energy" (regardless of the quantum difference, which is way too complex for this, the coil is not showing saturation in either half, so there reasonably would be a different charge)?

Is this "over analysis paralysis" or is this something to be learnt from it? :?:

Has anyone seen this on cars they've repaired (or not repaired) such a coil dwell and current difference between its halves?

I await the lightbulb moment if anyone can shed anything, I'm here to learn! :idea:

Thanks
Richard
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Re: Fiesta 2003 1.3 Misfire on Cyl#1

Postby STC » Tue Aug 01, 2017 11:11 pm

The single misfire (#1) being worse than it's pair (#4) could be possible due to many internal issues within the coil, it does not always fail both halves equally fully at the same time (there is wiring per cylinder than can short to ground rather than per pair!) wasted is not total commonality.


Dependant on the polarity of the spark - I see that.
A fouled, Closed Plug Gap can render one useful and the other useless - I see that too.

A common cause for coil failure is often Secondary side conductors open or spark plugs. That may well be why Ignition Coil Warranty will require replacement of HT leads and Plugs for it to be valid.

No mention of Spark Plugs above. It seems that with a Petrol Misfire the Coil gets it first, Injector next and in some cases the ECU - all before the Plug and leads - The one thing that can cause Havoc - Just my experience.



Your second post, Voltage, yes after discussion with a nice tanned bloke back from his hols this morning


I guess you refer to my buddy, the lovable Mr Martins ?


Looking at the primary trace, see below, all 4 spark burn times are 1.4ms +/- 0.1ms.


Acceptable !

and a burn voltage (primary) of 34-40v


Tail pipe emissions please ? All 4 gasses !
Last edited by STC on Wed Aug 02, 2017 8:02 am, edited 1 time in total.
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