[X300] Mystery....

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[X300] Mystery....

Postby neil_waveley » Sat Oct 19, 2013 10:08 am

Thanks for allowing me to post here, I hope to draw on someones expertise and experience inorder to solve this problem which has been exercising the minds of members of the Jaguar-Lovers Forum since early April, the total number of posts must now total several hundred. Steve Sparrow has infact used a borrowed Picoscope early in his investigation, I'll outline the problem and copy & paste in his first post on it which can be followed on the J-L website ( http://www.jaguar-lovers.org ) in the X300 Forum:

The car is a UK X300 Sport, which first had this problem after the owner switched to Sport mode and used Kickdown whilst traveling up a steep gradient since then the car would start and run for about 40 seconds at which point it turned out that the coils on cylinders 1, 2 & 3 ceased to fire, loosing power and idling roughly. thus followed a long saga and when Steve eventually examined the exhaust the forward cat on Bank 1 had been destroyed and after much agonising by the owner he decided to try fitting a replacement which was done recently but Steve noticed that it became yellow as it heated due to the start of a meltdown when Bank 1 shut down and that is really where we are now.

I'm afraid that it will be quite a long read especially if you backtrack through all of it from the beginning, but I hoping that this may trigger something that we haven't thought of.

Steve's 1st. post:

Every 6 months or so I'm delighted to receive a car that many
have 'had a go at' but not quite managed to fix. Unsure whether
this makes me the ultimate trouble shooter or simply the last
resort, I just carry on regardless!

The latest problem is a really interesting and I haven't
solved it
yet. As you would guess, I've checked through many basic and
not so
basic things which I won't list here, there are too many, but
please don't be offended if suggesting something I've
already done .

X300 4.0 150k miles

The Symptoms;

The engine will start immedialtely from 12 hr. cold and run on 6
cylinders for about 40 secs.

After that, it will stumble and drop onto 3 cyl.s only, the
exhaust
wreaking of petrol. It will misfire, backfire and the eventual
stall will see it refuse to start again. After 12 hrs. or so it
will start once more and the cycle is repeated. The Crank Sensor
has been replaced as step 1.

After very (very!) much ado, and checking for a blocked B1 Cat.
I've confirmed that B1 cylinder ign. coils (1,2 and 3) are not
firing after the initial 40 seconds running, although they still
have 12V supply on the white wires. Naturally, the swapping
around
of coils and plugs etc. has been done. Coils 123 will run cyl.s
456 with no problems when moved, as will the plugs.

Trouble Codes = None. Pending or Latent Codes = None.
Compressions are 160-170 psi on all 6.

STFT's when running are on + 24.2%. Both B1 and B2 02's are
flatlining at 0V, the TPS is working fine, as is the Air Mass
meter. No air leaks are present, smoke machine confirmed. B1
fuel
injectors are working and all 3 cylinders are inducting air.

At close of play today I have pulled the ECU (no water
damage) and
will try that on another properly runnning car on Monday to see
what it does. I can accept that the ECU may be failing to fire
(earth out) one coil, but why would it fail to fire 3 in one
bank?

This brings me to my question, I'm hoping someone will know the
answer as I suddenly realised I don't. Are X300 coils fired
truly
sequentially, or are they fired as a group of 3 with a wasted
spark?

I have the wiring diagram. The fact that all 6 coils have
individual green negative wires with different trace colours
suggests they are fired sequentially, but it is possible that
within the ECU, those 3 wires for one bank all go to the same
place, and that could explain the dead 3 coils.

All of this makes me wonder if the ECU actually shuts down a
bank
of 3 cylinders if it see something it does not like? I've always
beleived X300's not to have the 'cylinder shutdown' that Merc.s
have, but maybe they do, and it does so 3 cyl,s at a time
but just
never been seen before??

A MORE RECENT post:

Neil and All,

I think I need to pare it back to basics, as much for me as
anything as I can't get at my earlier records on this thread.

Symptoms

The engine runs fine on petrol until it is quite warm, where
misfiring and backfiring will begin. Eventually, coils 123 do not
spark the plugs at all, although there is a good 12V feed to the
positive side on all 6. There is no signal., ripple, spike or
waveform of any kind on 123 coil negatives when coil failure
occurs. When this happens, the front manifold goes cold.

There is significant 'noise' in the 12V supply.

As a result of the coils not firing, the B1 front cat. glows yellow
with heat as it burns the unburned petrol/ air mix that is being
exhausted.

The problem is definately temperature triggered as the engine will
start just fine after 12 hrs or so of cooling. The colder it is
before a start, the longer it will run before the misfiring begins
and the coils eventually stop firing. I have yet to measure the
exact coolant temp. the failure occurs at.

Remedial Actions

The exhaust has just been fitted, it has no blockages but it does
have 3 good cats, the original front one was burned out by the
symptoms above.

The car has been fitted with 2 other identical ECU's which made no
difference at all, and ran another car just fine, as does the
original ECU.

All 6 compressions are fine.
All 6 injectors have good seals at the manifold.
Cam timing is correct.
Valve timing is correct.
No air leaks are present
The Alternator has been removed to rule out earthing or other
electrical disturbances.

All of the earth points front and back have been checked and
cleaned. The engine to body earth strap has been removed and
cleaned.

The battery is brand new and does not dip below 12V.

A temporary 12V supply was rigged to the coils which made no
difference.

All of coils 123 have a good path to the ECU as continuity has been
checked.

The coils pull 6.2 A when working, which falls to Zero Amps when
the failure occurs.

The spark plug gaps were narrowed to 0.020'' to reduce spark
voltages and load on the coils - no difference.

Other parts swapped (known good ones) and the originals proved OK
on another car;

All 6 coils and spark plugs
Crank sensor
Cam sensor and body
B1 Knock Sensor
Air temp. sensor
Coolant temp. sensor
Throttle body incl. TPS
Air Mass meter
Security module
Ignition Switch

The only trouble code which has been logged is P1621 - 'Engine
Control Module' which may be caused by me swapping parts, I will re-
confirm this.

That's pretty much where I am.
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Re: [X300] Mystery....

Postby Robski » Sun Oct 20, 2013 6:12 am

1) link no worky ?
2) who's Steve Sparrow ?
3) why all the swoptronics if armed with a Pico ?
4) high fuel trims & 0V on O2's,it seems Mr Sparrow doesn't understand the system much ??
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Re: [X300] Mystery....

Postby neil_waveley » Sun Oct 20, 2013 8:01 am

1) Try: http://tinyurl.com/nmtbhwu
2) Steve Sparrow owns Go-Lpg, a company specialising in Automotive Gas Conversions: http://tinyurl.com/p6sxtzq
3) he borrowed one after a month or so of investigation, but although it confirmed that the coils on Bank 1 ceased to fire that does not diagnose the mechanism causing it to happen. If you or anyone here knows what might be the cause that would be a break through as no one else has explained it as yet.
4) That is a bit harsh, but you have to trawl through the whole thread inorder to gain the flavour.
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Re: [X300] Mystery....

Postby Chris_W » Sun Oct 20, 2013 8:31 am

Here you are Rob

http://forums.jag-lovers.org

I had a quick look and I think I found then thread but you need to join and I am not feeling inspired this morning, Maybe later.

Those fuel trims and O2's are a very bit clue though Surely?
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Re: [X300] Mystery....

Postby Robski » Sun Oct 20, 2013 8:39 am

cheers Chris TBH I CBA with joining just to read that thread neither :?
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Re: [X300] Mystery....

Postby neil_waveley » Sun Oct 20, 2013 9:14 am

1) Try: http://tinyurl.com/nmtbhwu
2) Steve Sparrow owns Go-Lpg, a company specialising in Automotive Gas Conversions: http://tinyurl.com/p6sxtzq
3) he borrowed one after a month or so of investigation, but although it confirmed that the coils on Bank 1 ceased to fire that does not diagnose the mechanism causing it to happen. If you or anyone here knows what might be the cause that would be a break through as no one else has explained it as yet.
4) That is a bit harsh, but you have to trawl through the whole thread inorder to gain the flavour.

I might add that J-L forum comprises mainly of people who own, drive and maintain their own cars and few are professionals in the automotive trade or trained Diagnostic Engineers specialising in auto electronics infact I can only think of one who currently is. The above URL link should I hope allow you to read through the posts last April. Our collective knowledge in this area is limited to the point of being general hence this plea for added information as no one has come up with a rationale that explains how or why those 3 coils should shut down.
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Re: [X300] Mystery....

Postby neil_waveley » Sun Oct 20, 2013 10:54 am

Rob, if may address you as that, I just found out that Steve's friend who loaned him the PicoScope is a Pico member and has had hands on experience on this car on two occasions over the months that Steve has been playing with it perhaps he'll chip in and be kind enough to give his view on this.

Steve's latest post is thus:
As an aside, the EM professional that came to look at the car twice over
these months (for which I am grateful) is a PICO member.

I have some plans for tomorrow's session;

At some point I'm going to replicate the partial blockage of the
air inlet duct just to see if I can make 456 go down again, instead
of 123. I agree with it being a clue, I just need to know how it
fits in. If I can force the problem to move to 456 I'll be looking
hard at the air mass meter data, not that the AM meter itself is
thought to faulty (proven good by fitting to another car) but the
wirimg to and fro could be to blame.

In addition I'm going to re-confirm that B1 and B2 O2 sensors are
switching and connected correctly (done by running OBD and seeing
which one flatlines) and then deliberately swap them over to follow
the idea of only 02's having authority over a bank of 3 cyls. If
the problem moves banks, then we're onto it. I've done this before
but at this stage I have to begin going over things a second or
more times.

I will also monitor coolant temp. from a cold start to see what the
breakdown temp. is, and see if it is repeatable. If so, I might see
what happens (after subsequent cold starts) if the coolant temp.
sensor is disconnected, depending of course on what the defualt ECU
reading would be. My guess (as if I had chosen it) would be 15C.
Again, I have done most of this before, but I have to revisit.
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Re: [X300] Mystery....

Postby KimAndersen » Sun Oct 20, 2013 11:30 am

Hi

With your story on my mind i would take a closer look on the short term fuel trim at 24.1 % and why they are so high ?

My first thought are intake air leaks in your engine. With both`s oxygen sensors value at zero volts, i would look into this first. With a normal oxygen senor a value at 0 volt is a lean condition and the ECU has to respond to this by adding fuel.

What could cause a lean condition ?

If you ask me i would say there are some obvious things you can look for as a stuck PCV valve or a secondary air pump or what about the EVAP system.

This is just some of the diagnostic routes you may take, its your decision what path you choose to take.

Haven't got a answer to why it disables the ignition to cylinder 1 to 3 other than its related to readings from the oxygen sensors.

Regards
Kim
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Re: [X300] Mystery....

Postby Robski » Sun Oct 20, 2013 8:29 pm

Neil,

It's no good copying & pasting the last post for me as i have not/am not joining the forum just for that & it means nothing to me as i don't know the previous posts.

Neither is it any good translating between this Jag forum & the Pico forum for other individuals (of the forum), let the 'Pico member' come on & explain what's been done/not done & what armory he has or Mr Sparrow. It may be a different case for other members here if they wish to register with that forum as they will know more than me by doing so.

I know what i would be trying on first start up after being stood, but it depends on this 'Pico member's' armory.............
Also have something else in mind but let's have the main man on the job join & tell me/us exactly what's been done & not.

4) That is a bit harsh, but you have to trawl through the whole thread in order to gain the flavor.

I don't think so, just factual. Understanding fuel trim analysis is vital in diagnostics & tells a big story.

Has this Jag had an LPG conversion per chance ?
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Re: [X300] Mystery....

Postby neil_waveley » Sun Oct 20, 2013 9:46 pm

Thanks Rob, I hope your Pico member will come in as he apparently has hands on experiencewith this car/ problem and I'll ask Steve to prompt him.

Yes it can and has run on lpg but that mod has been reversed.

Sorry but because I'm being moderated there is quite a lag after I post anything before it's on the board.
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