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        General >> Problems >> 24v: cylinders 1-5 not firing SOLVED
        
(Message started by: Cosray on Jun 7^th, 2009, 3:17pm)

Title: 24v: cylinders 1-5 not firing SOLVED
Post by Cosray on Jun 7^th, 2009, 3:17pm

Hi all, my previous post dealt with a blown ignition coil on my Cosworth, for cyl. 1-5. I got round to fault finding and repair only this week.

Replaced the blown 3-coilpack - only to find the engine was still on 4 cyl. and the coil for cyl. 1-5 got warm
again within 2 minutes; the other 2 absolutely cold.

Replaced the EDIS6 and got same indications. Measured 4 leads from coilpack connector against ground: the
PLUS from the Ignition switch (12V) + 3 leads for each coil to the EDIS6, pins 10-12-11. All 3 coils are on switched PLUS; the EDIS6 when ordered by the EEC-V grounds each coil lead for 2 simultaneous sparks.

Lead 8-PC78 (White/Blue) on EDIS pin 10, for cyl. 1-5 coil, proved shorted against ground, thereby permanently activating the cyl. 1-5 coilpack, generating 200Watts of heat, which led to the blow-up. Eureka ;D!

Cut lead both ends & bypassed. No joy, engine still on 4 cyl.; coil not sparking. Changed EDIS6 once again; no joy. All plugcables per coil (1-5, 4-3, 6-2) measured in series 20kOhm total. All plugs clean; but no coil output for 1-5.

Engine runs surprisingly stable on 4 on idle, 800 revs, petrol smell, throttle gives little power, sluggish. Sensors and IACV work fine: engine stops when its connector is pulled.

So then tested back the connection from EDIS6 towards EEC-V, which uses 3 leads for each EDIS6 input in a separate metal shielding within the bigger loom. Unusual values in Volts (identical for both EDIS):

Key ON/Engine OFF:
EEC-V to EDIS Pin1 Pin 3 Pin 4
Meter on DC
11 0,06 0,06

Key ON/Engine ON (idling on 4)
EEC-V to EDIS Pin1 Pin 3 Pin 4
Meter on DC
6,58 0,93 0,22
Meter on AC
14 1,5 0,1

Since I am measuring pulses with a DC bias my values are not exact BUT: they should be identical. Pin 1's values stand out, so suspect.

I then fully cut all ends & bypassed the 3 leads as well as the shielding direct from EDIS6 to EEC-V: same perfromance and values.

Then when I disconnect the suspect pin 1 the engine stops.
When I disconnect pin 3 there is a slightly noticable rev. increase..!?
...when I disconnect pin 4 there is no change whatsoever... (in idling speed)

I am totally baffled... does anyone have any clues here?
Looking forward to any suggestion!

Ray

Title: Re: 24v: cylinders 1-5 not firing
Post by adamn on Jun 7^th, 2009, 9:21pm

hi

citing from http://www.dainst.com/info/edis/edis.html :

pin 1 = PIP, output, open collector, default +12V, goes to ground when impulse is given to EEC

pin 3 = SAW (spark advance word), input, generated by EEC,
if disconnected, then EDIS goes to default spark advance (probably resulting to yours rev increase)

pin4 = is a ground bypass wire between EEC and EDIS, used by EEC as a reference ground for PIP and IDM (the internal logical signal for EEC's processor is taken by differential comparator with hysteresis, where minus input is connected to pin4 and plus input to desired 12V-level signal, output is 5V CMOS)
pin4 is connected inside the EDIS directly to pin9.

the EDIS does not neet EEC to work, but EEC need EDIS (PIP) to fire the injectors...

---

DC about 6.5Volts on pin1 when engine running on idle, seems as there is some signal switching between ground and 12V, resulting to this value, also KOEOFF is steady 11V, also ok

definitelly - you need an oscilloscope, to compare crank sensor output and PIP output.
there might be missing teeth pickup, or faulty wiring between the sensor and EDIS.
EDIS also has problems when crank sensor is connected the opposite way (should be + to + and - to -, but there are no markings on the sensor's body, unfortunately)

also, btw., the IDM signal (pin2) reports to EEC if the desired coilpack fired (after each firing), so using the OBD-2 lead, you should be able to read the DTC

the IDM is also used as dashboard tacho gauge output, so if the tacho gauge shows the correct rpms, then EDIS is firing all the coilpacks, otherwise it will show lower rpms then is the real number.

well, just a few thoughts, hope you will get it back on road soon!

Title: Re: 24v: cylinders 1-5 not firing
Post by Cosray on Jun 7^th, 2009, 10:28pm

Thank you Adam for your thoughts and additional documentation. I read the piece a while ago when I not needed it, so now it makes even more sense. The graphs and text are of high standard.

I am more puzzled by my one coil not firing as I saw my thought confirmed that the EDIS6 is autonomous.

So I am trying to follow and add to your reasoning here as follows.

EDIS6 needs the EEC only for the niceties of Spark Advance. So why does my simple one coil not fire? It has a PLUS on one side, the other goes straight (bypassed the loom) to EDIS6, same as the other 2 that do function.

"the EDIS does not neet EEC to work, but EEC need EDIS (PIP) to fire the injectors... "

Now, all Injectors MUST work since 4 cylinders surprisingly keep the engine idling reasonably well and I smell petrol emitted from the other 2 non-firing cylinders.

Also, if I cut the EEC lead to pin 1, the engine stops. It follows that pin 1, + its signal for the EEC needed to activate the INJECTORS, is very clearly present and functional.

My tacho functions as well and sits around 750-800, so the IDM signal on pin 2 is present and functional.

When I cut the lead to pin 3 the engine idle speeds increases ever so slightly, maybe 20 revs or so. Ergo, the SAW is present and, by cutting it, the EDIS6 becomes autonomous again.

So -- why the doesn't coil 1-5 fire and the other 2 coils do!?

It all started with a burnt-out coil because of coil 1 permanently grounded because of a wireshort to ground.

I cannot think of a valid reason right now why or how other elements of the system malfunction. All requirements seem to be met.

TWO faults in one case? The odds are too high -- unless they are related, but how?

My car is at the village garage and their OBD equipment is getting 'updated'. (= Mended). Looking forward to see what that tells me. Probably a DTC for coil 1 not firing!

Could it be that, as coil 1 has not fired for a long while now, the EEC is now treating it as 'out of bounds' and inhibiting EDIS6 to fire it?

Thanks again for your support,
Ray

Title: Re: 24v: cylinders 1-5 not firing
Post by adamn on Jun 9^th, 2009, 8:29pm

hmm puzzling it is

so you say you did:

1] you have tried a new (or a different EDIS) (otherwise -> EDIS broken)

2] you have completly replaced the wiring between EDIS and coilpack (otherwise -> wiring shorted or broken)

and it still not works? wow

you said disconnecting SAW signal made no change (changed the revs, but not cured the problem), so I guess EEC is out of game

] are you really sure it is not firing?
if it is not injecting fuel... just thinking...

If you got IDM right (tacho shows the CORRECT rpm), then EDIS got the returning voltage spike from primary coil, when it fires, and creates a pulse on IDM then
Also, it might be worth to check the "desired" and "real" rpms reported by OBD-2 (using Pepper's VE tool, it is in the advanced list). The numbers should show the same as the tacho do.
The best thing is to have a two channel scope, to monitor the current flow through the connection between EDIS and 1-5 coilpack, and the second channel on PIP or IDM, just to see if everything is synchronized.

the best idea might be:
try to change the 1-5 pack for some other, eg. switch the primary side connection to EDIS with any other pack, and also switch the secondary side appropriatelly.
this will show, if EDIS or COIL pack is bad,...
... or ???

a.

Title: Re: 24v: cylinders 1-5 not firing
Post by Cosray on Jun 9^th, 2009, 9:31pm

Hi Adam, thanks for your thoughts.

Tonight at sunset I completely backtracked each and every circuit while measuring and made some very lowdown measurements on each and every node between Coiklpack, EDIS6 and EEC-V.

Guess what -- on the coilpack the secundary of coil 1 is open... so interrupted, burnt, open-ended so no spark either side... ;D

This is why cyl. 1-5 is not firing BUT the EEC-V meanwhile is getting more or less proper feedback information: coil 1 PRIMARY is fired and will produce some EMF to register; so IDM is allright, so there is a SAW that will only slightly better i.e. increase revs... however no spark at the plugs...

The EEC-V does not know ther is a bad secundary coil not producing sparks.

I am getting a new 3-coilpack soon and will let you know what's next.

I mentioned to you earlier why I could not understand what was stopping the autonomous EDIS from firing coil 1... while the engine happily idled on just 4 cylinders fored from coil 2 and 3...

A broken HT secundary coil... would you believe... I bought this coilpack from a breaker's and of course, I never thought of doing 6 preventive measurements on the coils... did not Pres. Nixon say: "trust, but verify"?

To be continued,
Ray

Title: Re: 24v: cylinders 1-5 not firing
Post by Cosray on Jun 10^th, 2009, 10:37am

As a precaution I tested the original faulty configuration before starting to work.

Connected battery, all doors opened up since I had earlier opened the driver's door by key. Turned the ignition and the engine happily ran a bit wobbly on 4 cylinders, as before.

Then I exchanged the two coilpacks, making sure all I removed and replaced were the 4 bolts, the 6 plugcables and the 4-pin primary connector. Engine would crank but not fire... no smell of petrol either... so no injectors opening.

Looks like PATS has (again) immobilised the EEC-V.
When exchanging the coilpacks I had left the key OFF in the barrel and the battery on.

The remote works including double locking and alarmlights flashing twice. It will also properly unlock but apparaently not reset this immobilisation.

I had this previously and when I would return the next day or so everything is fine. Let's hope so now. I disconnected the battery just in case and left it there.

Can anyone explain why exchanging a coilpack should immobilise the EEC-V? It is driving me nuts,
Looking forward,
Ray

Title: Re: 24v: cylinders 1-5 not firing
Post by adamn on Jun 10^th, 2009, 12:46pm

well, it should not.

see the PATS manual, at link removed by admin

a.

edit: link fixed ( thttp -> http )

Title: Re: 24v: cylinders 1-5 not firing
Post by Cosray on Jun 11^th, 2009, 2:41pm

Yesterday I installed the new coilpack and started the engine. It cranked but did not start: no Injectors working, EEC-V somehow immobilised again. I then disconnected the battery, locked the car manually.

Came back today, put the battery back on, started the engine which ran at once on 6 cylinders and had normal power again, even cold. Eureka. ;D

I had to switchoff the engine to open the boot and of course it would not start after. It cranked allright but no petrolsmell, no injectors working, EEC-V immoblised.

I tried a few cycles of doors locking with alarm on/off to no avail. I disconnected/connected the battery after 5 minutes - no joy. By now I know that when I return after a few hours it will go again. ???

What is causing this behaviour? Anybody have a clue?
Will reading DTC's give an answer? It is maddening.
Looking forward, Ray

Title: Re: 24v: cylinders 1-5 not firing
Post by adamn on Jun 11^th, 2009, 7:39pm

hm

if it would be PATS, you will get info by the PATS red LED, and
there will be also PATS related DTC stored (OBD-2).

if I ever got EEC imobilised (but engine was cranking using starter-motor), it was always because of the
bad wiring (exactaly by missing PIP signal, and this is easy to check, connect OBD-2 and try to read the actual RPMs reported by EEC. If you are cranking and it is 0, then the PIP is not coming to EEC).

but as you said,
if your engine is one time working all right (engine running etc) and then the other time not,
and all components of EDIS are (somehow) checked, I will definitelly suspect the wiring.

rebuild all the looms for EDIS, including the connections between EEC and EDIS.

get an oscilloscope, check all signals, this is much more usefull than everything else.

just remembering - my case was, that I needed to rebuild the EDIS-crank sensor wiring and also the EDIS-coilpack wiring. And since then I had no problems at all.

hmmm...

Title: Re: 24v: cylinders 1-5 not firing
Post by Cosray on Jun 11^th, 2009, 8:59pm

Thanks Adam for your thoughts. Yes, you may be completely right. I will need someone else to start the engine while I do all the measuring. My battery lasts about 25 starts... will use a starterpack.

BTW My PIP, IDM and SAW signals between EDIS6 and EEC-V are bypassed completely by separate wires.

Tonight I went in just to connect the battery and start. The engine was cranking but no firing, no smell of petrol. It was 6 hours since it successfully ran on 6 cylinders and then, after a contact switch off to open the boot, it never started again. Experience say it will start in the morning, but why?

A friend suggested a thermal abberation, but where? After 5 minutes of succesful idling? In The EEC-V?

Another suggested an open CMOS-circuit, charging up to max. voltage, only to lose that charge overnight. But where?

I will have the EEC-V completely cleared of DTC's and its memories and other stuff tomorrow and start all fresh all over. Hopefully clears my mind as well..!

Ciao,
Ray

Title: Re: 24v: cylinders 1-5 not firing * SOLVED *
Post by Cosray on Jun 21^st, 2009, 10:23pm

Hi all, solved the problem at last.

Just a recap: 2 months ago after having fueled started the engine which then ran on 4.
Tried every trick but 10 mins later the coilpack blew up. Coil 1 was redhot.

Got a new coilpack, replaced it. Engine ran on 4, coil 1 got warm after 5 mins. Switched off and started searching for a clue. Found a short against ground in coil 1's lead to the EDIS, so the coil was permanently ON and generated 200 Watts of heat.

Bypassed the lead but still on 4 cylinders. Nothing made sense since all readings were normal.

Went on a holiday, came back, had a bright hunch and measured coil 1's HT- secundary coil -- it was blown, open-ended -- so no sparks there!

Enter a fresh coilpack. Engine ran on 6 immediately but never restarted after. Sometimes it would start and then never again in 24 hours or so.

By then I was suspecting PATS, the EEC-V etc. Nothing made sense. I was about to give up but decided to replace the CPS, the Cam Sensor and their wiring as a last resort.

Yesterday I completely bypassed the loom between CPS, Cam Sensor, EDIS6, coilpack and EEC-V by pulling and bundling new wires while isolating various sectors of the existing loom so they could not interfere.

Bingo. Ran on 6 again AND restarted reliably time after time, as normal.

In reflection the cause is most certainly the brittle isolation of the original shorted lead from the EDIS6 to coil 1, which shorted against a ground.

This ground being the shield (pin 7) of the 2-wire shielded cable from the CPS to the EDIS6 (pin 5, - and 6, +), causing the floating wires of the CPS to become unbalanced against ground during running of the engine.

Apparently the processor inside the EDIS6 accepts this unbalance while it happens, but does NOT accept this after hot restart and will not issue the PIP signal to the EEC-V, stopping the injectors from opening.

After the engine cools down the temporary unbalance resets because of thermal crimp. That particular loomsection runs along the very hot front-end side of the engine. I have not bothered to look inside but I am sure the wires' isolation is all crumbled and jumbled up.

Moral: whenever these strange, intermittent non-starting faults appear: replace & rebuild the forward loom between CPS, Cam Sensor, EDIS6, coilpack and EEC-V asap.

Many thanks to A d a m N for being a great & confident sparring partner in this hair-pulling situation.

Ray ;D