Engine Stops

[springelec]

Hi Guys,

Well that makes three of us. I'm also an Electronics Engineer with a lot of design experience with electrical stuff too and my thirty years of design engineering experience tells me two things.
Either:
1) X308 circuits haven't been design properly and are therefore unnecessarily sensitive to battery woes.
OR
2) X308 circuits have been designed properly and changing the battery masks the real faults.

As yet I don't have enough information or X308 experience to decide which of these two options is right. However, I'm inclined to believe the X308 circuit were designed properly because I'm old enough to remember seeing some Jag video on the Tele, years ago, showing the car being tested down to -40C (-40F) and being driven across Death Valley (+40C, +104F) in the States to prove the car's reliability. If these extreme temperature tests didn't pull out any residual battery related problems, nothing else would.

Also, most people don't realise how sensitive lead acid batteries are to temperature, except in the Winter when their battery suddenly dies. Lead acid batteries are also critically sensitive to heat and I suspect thses facts were behind Jags decision to test their new X308 both hot and cold.

So on the balance of probability, my guess would be that option 2 is the right answer and X308 faults are being masked by a new battery. My justification for this conclusion would be that Jags' original hot & cold tests were performed on a new car which would be free from potential errors caused by old wiring and connectors. Hence the reason why I was floating the idea that strange bugs with a ten year old car could be caused by wiring and connectors. Age and its effects can be simulated, but never really tested, not really.

So where does this discourse leave me ?.

I've noticed that there are a couple of earth return lugs near the ABS unit which look a little the worse for wear, so once the weather allows, I'm going to take tham apart and wire brush all the lugs and the chassis point to return them to their original clean, bright and electrically good condition.

After that, I'll monitor the car for the same or any other bugs that surface.
I will keep tabs on the battery as well, because although I don't understand the connection, BB and others may well be proved right and the simple expedient of changing the battery may be the answer to my problems.

I'll keep you all posted.

In the mean time, I would be very interested to read BB's article about tackling the timing chain tensioners.

Best wishes and happy motoring to all members.

Springelec

[joejag308]

Springelec.......you seem to know what you are doing, i cant comment on your progress but i must sipulate for the record your information and your solutions are of your own assumption.
I do wish you well in your efforts, and if you are correct and the faults are caused by your findings it will no doubt benefit all in this forum.
But i can only say the normal fault finding on 308s is left to the usual methods as far as i am concerned re this forum, which are via the experts whos solutions and reccomendations we hold very highly.
They are the guys we rely on, they actually work on the cars day in day out.
As i have said i cant doubt your findings as i dont have any knowledge of the detailed electronics and electrical workings of the vehicles but i dont want the members in here to lose faith in the normal methods of deduction.......i do wish you well however......Joe

[springelec]

Hi Joejag308,

I'm not quite sure why my comments have caused offence or indeed why I've attracted a slap on the wrists for my comments.

Having re-read my notes, I can't see why I you've suggested I've impugned anyone's character or technical competence.

I've never suggested that other members don't know what they're talking about, so I'm at a loss to understand what offence I've caused.

My background is R&D and I am merely applying my R&D discipline to find cause and effect.

I have accepted that changing the battery may cure all ills, but with caveat that changing the battery may merely mask the real fault not cure it.

As a practising Design Engineer, I know that machines are designed with the best methods, intent and cash available at the time. However, design engineers cannot predict all methods of failure and ultimately a balance has to be struck between the test cost and return on that investment.

Whilst Jaguar would have invested quite heavily under Ford's management to make the X308 as reliable as possible, it would still have been to a budget and that always means compromise and they may have failed to find all the remaining bugs lurking in the wings. The Nikasil episode in their history is a classic example of what I am trying to explain.

This is not a criticism of Jaguar or its methods, just a statement of real design engineering and the financial limitations imposed on it.

I remain open minded about the reason why my X308 sometimes stops for no apparent reason and it may well be down to some weird connection with the battery voltage. However, I believe there is a deeper explanation for this fault which I would like to find.

If I do find it, I would hope that I may discuss my findings with this forum without fear or accusation of upsetting cherished beliefs or personalities.

Best Wishes

Springelec

[Brakebuster]

i for one have not taken any offense at any comments from anyone on here so far,

Joe, i think your getting hold of the wrong end of the stick a little,

but

i can see however ,even though a plausible reason for your electrical problems has been put forward, from members who like me have suffered from the same issues , you seem to be looking for further problems that may or may-not be there,
i'm not saying you dont have another underlying problem, but Jaguar Tech time is expensive, and sometimes fruitless with finding the ' fault '.

i have recently spent £2k on a new ECU for my XJ8 after a code was being thrown for a faulty O2 sensor , which failed the MOT , the fault was found to be the ECU not turning on the O2 sensor , which under the new ECU has worked perfectly....
it was only a full diagnostic session that found this issue, which wasnt cheap....

what i'm trying to say is, that if you have an original battery of unknown condition fitted, buy a new one for peace of mind , at £80 its about the cheapest thing you can do to try and rectify these ' ghost ' faults ,
once the new battery is fitted, run the car for a week, and see if any of these codes come back , if not, your in the clear, if so, get it booked in for diagnostics,

if your near Gloucester, i can plug it into my laptop as i have Jaguar OBD2 software and leads that will read the codes......this goes for any member wishing to see any codes.......

with regard to your earthing points, some members in harsh climates have found corrosion at these point, i dont have to tell you about high resistance and loss of voltage at these points, but some can cause issues, dont forget the main point in the boot by the battery, also the positive busbar lugs in the engine bay on the bulkhead , clean and grease these to,

finally, dont forget your car is getting on in years, and the main car body was inherited from the XJ40 , we have come to expect perfect cars from new, but we forget that they are not new some times, and age has its effects on every system of a car , used or not ,

i hope you sort the problem asap, and get to enjoy driving it, as they are a joy to drive when running well, and try not to think that it might stop at any moment, buy RAC cover ( as i have ) , so then it doesnt matter, lol

dont forget , there is a throttle body recall for any car on an AJ26 V8 engine ( pre 1999 ) , as it cuts the engine at motorway speeds, but allows the car to start once pulled over , this IS a design fault, phone Jaguar, give them your VIN and ask if the TB replacement has been carried out if your car qualifies , some later cars only require a flash of the ecu to rectify

BB

[springelec]

Hi BB,

Thanks for all these notes, Sage words indeed.

You could be right and I am looking too deep into this problem.

I picked up on your comment about OBD2 diagnostics because I'm considering getting my own diagnostic equipment so that I can study and monitor the error codes as and when they appear. If you've got something that reads X308 codes, I would be very interested to see what you've got before I buy.

I live near Worcester which is up the M5 from Gloucester, so perhaps you could call me to arrange a mutually agreeable date and time to visit.

Tel: 01386 556061 (Please leave message if I'm out and I'll call back)

Thanks

Springelec

[Brakebuster]

Worcester......

you car will have just warmed up by the time it gets to Glos, lol

as for the timing cain tensioners, follow the link below
i did do it nearly two years ago though....
http://www.jaguarforum.co.uk/viewtopic.php?f=35&t=11332

it will give you an insight into cost and what needs doing if your on old tensioners,

i have also replaces the water pump, thermostat and belt rollers , along with new front dampers, new discs all round, steering wheel, rear view mirror, door mirrors , armrest , dash clocks , etc etc
and am currently replacing the front lower wishbone bushes and ball joints , in fact i only took out the nearside one ten mins ago, and am about to drive out the bushes , the offside was finished this morning , and loads of waxoyle underseal was sprayed round all the metalwork making it look much better

BB

oh, and i'm fully restoring a twenty year old 5.3 V12 XJS , must be mad.....muhahahahahahha

[joejag308]

Springelec............i have not insinuated that you have caused any offence.
What i am saying is ....as i have explained to posters in the past who are obviously more experienced than other members, not to be too technicle with their assumptions or comments unless its personal fact.
We do appreciate members showing experience and hopefully we can all learn from it but we do try and keep things in an understandable format.
The basic format is that if a member has a fault and we in here dont know the answer we have experts who we can approach on behalf of the members for the answer......re the battery fault used many times as a basic diagnosis, i did post an answer that i personally had a fault with the electrics which i submitted....the answer came back as being a battery fault even though the battery passed most electrical tests.......but it did happen to be the battery....hence the posting re most of the minor electrical faults.
It does seem that you and Brake Buster etc are qualified people IE electrical engineers.......all power to your elbows.....but the majority in here aren't.......i have to try and keep it so everyone can understand what is going on......so no offence meant by my comments at all........Joe

[paulbarrie]

Having bought a new battery approx 2 months ago, I have still been having the problem with these error codes and engine being put into limp home mode. The last time was on the outside lane of the M25 but luckily it was mid morning and not too busy and was able to get to hard shoulder. Turned off engine, waited couple of minutes and restarted. It is very difficult to have confidence in a car which puts you in a high risk situation.
I took car to specialist in Luton who advised that the front fuse boxes had a bit of a burnt smell. These have now been replaced (bit drastic?) and so far, no further problem (I'm keeping fingers crossed). The garage advised that they had experienced all sorts of isuues caused by these fuse boxes, e.g. one customer flashed his headlights and his engine cuts out.

I'll keep you informed if any further problems.

[springelec]

Hi Paul,

It's coincidental you've posted a note about the XJ8 engine stopping problem because I believe I've sorted out why my XJR stopped.

I would like to post a pdf document to explain the fault on my car, but don't know how to up load the document to this forum.

Suffice to say, my gut feeling was right and it was caused by a tired connector in the engine bay, but my pictures would save a lot of words of explanation.

So far, I've enjoyed about four weeks of trouble free motoring instead of the car stopping at least once , if not several times per journey.

If BB, Joejags or anyone else could help, I would be happy to upload said document over the weekend.

Thanks

Springelec.

[jedstone]

Gentlemen,

I have been following this post since started by springelec in late July as that was about a month after my problem began. I must advise that I am a simple sailor from sunny Gosport - and O-level General Science was decades ago so feel very 'umble in your company. I also have to have deep pockets as maintenance of my 2001 SuperV8 is generally well outside my technical and mechanical capability.

My problem started after I floored the accelerator to flash past a lorry on the A1 in Northumberland on a single-track road and had pulled back to the left. I lost power, the ASC Fail/Trac Control Fail/Engine Fail Safe mode flashed up and I frantically looked for a lay-by. Ten minutes looking through the handbooks and not finding them any use I started and all was well. We were seven days into a round Britain tour which fortunately had no more problems (and as the right foor then became more cautious cracked 1400 miles at 25 mph).

That problem took place with a battery that was three weeks old. While I have not had a drop-test done I have tended to think that my battery condition is not a cause. I could be very wrong. Likewise my earth points seem as clean as a whistle.

A week or so later identical problem as I joined the M27; stop and re-start and half an hour later it happened for third time. This time the amber engine logo warning light came on and stopped on. Completed further 100 mile journey and returned 145 miles home all while showing warning light. Next morning it had gone.

Having read other posts I took the car to my local independant Jaguar garage and had the throttle body cleaned - no-charge, VG! All was well for a month.

Then similar near-miss (this time heading to the West Country for a fortnight on a dual carriageway overtaking slow-moving car-transporter with a gentle right foot on a long incline. Poor guy had to slow right down to let me over while the muppets behind kept flashing me. Again re-started no problem, again warning light remained on and stayed on for the weekend. Took car to West-Country main dealer - diagnosed replacement supercharger seals were required (part numbers NCC7735BA one and NCC77221AB two); had that done, cost £335. All was well for another month. I don't think anyone else has refered to a supercharger seals problem anywhere??

Then four times over a long weekend so on return home I cleaned the throttle body again (expensive stuff bought on e-bay) and all was well for just over three weeks when repeating the same journey as the second time it was almost an exact replica - joined the motor-way little bit of throttle and loss of revs. Warning light gone following morning. Then weekend before last it happened four times on the way west and five times on the way home. For all but one of those it was going uphill. Patience now wearing very thin. What a pain - everything else is great!

Since return home I have tried and failed to replicate fault deliberately - could be the engine was not hot enough.

Local opinion remains that it's a throttle body problem. Jaguar Customer Care confirm that my VIN is after that for which a serivce agreement was issued (identified by brakebuster I think on the XK8 site???). I understand there could be four or five versions of throttlebody used in the X308 supercharged production run?

So I'm looking forward to see what springelec manages to upload - and fully share paulbarrie's loss of confidence.

My apologies for going on so long Joe - hope I haven't exceeded my quota!

Jed Stone

(also trying to restore an XJ6 with serious rust)(and a Honda 400/4 with a rounded oil filter bolt-thread)(more cash required)

[springelec]

Evenin' Jedstone,

Just before I knock off work and go home to put my feet up with a bottle of beer or two, I thought I would reply to your post.

Your description of your car's woes sounds identical to my experience, so if you can let me have your private email, I will send the pdf to that address if you like, although I'll do it tomorrow, as I'm just about out the door.

Already sent a copy to another member this morning who kindly provided his email in advance.

Cheers

Springelec

[joejag308]

Jed i sympathise mate,its one of these annoying faults where it seems to be sorted then bang it happens again..........You seem to have your head scewed on re the fault finding and i dont want to add to your troubles unless i definitley know what your problem could be.........so please be patient and when you do sort it (i have no doubt you will ) please let the forum know just what it turns out to be.
If in the meantime there is anything we can do that is a help to you, just contact us and i will do whatever i can to help........in the meantime Dave Marks and Paul Grantham are there if you want to contact them with your problem....maybe just maybe they have that extra bit of knowledge you need.............Joe

[jedstone]

Thanks shipmates!

My e-mail address is jedatno7@ntlworld.com. I would be very grateful for copy of your info please springelec!

Joe will follow your advice -and contact the wizardsl

Jed

[springelec]

Hi Jed,

Emailed pdf as requested.

I hope my experience also fixes your problem.

Best Regards

Springelec

[joejag308]

Springelec.........is the information you have beneficial for the forum?
If it is, would you like to share it with other worthy members please.
All infomation re the 308 is helpful to the forum .......if its a cure for any 308 based problems please post it in the BB..........Joe