Fault code diagnosis and other tech talk

DeMort typed :-

"I get strange faults at work .. i often have to rely on instinct for want of a better word to know were to go ..

Faults like this help me become better strange as it may seem as after the fault is fixed (and you let us know ) i can analyse how i think about these systems .

I do actually use the forum as a training excersise to be honest .. thats what i get from this anyways ."

I take my hat off to you Mr DeMort :worship: The "instinct" you type of would seem to be as the result of trying to make sense of a control strategy that in times past could be worked out by looking at wiring diagrams and knowing the actions of switches in whatever situation was being studied...?

Since the use of digital technology it seems perhaps not only the end user has been inhibited in his desire to understand the method of operation of his vehicles control systems...but mechanics/technicians too..?

:frustrated:

Sure there are code readers which can spit out a line of mnemonics that someone has created in programming in the hope that whoever reads it will then be able to work backwards to find and repair the actual fault as ideally they should know the... design function specification... of the whole system..?

Yeah, well that is an ideal world situation is it not...?

Reality is likely to be far from that when manufacturers can be VERY protective of that which they determine as "intellectual copyright" thus they tend to seek to limit access even to technicians at various levels of the actual control strategies operation.. Thus a need to know structure inhibits the possibility of understanding and repair at levels where ideally it should NOT :frustrated: :frustrated: :frustrated:

Yeah, well what would you expect from someone who identifies himself as a Luddite.... :grin: [/quote]

very Asute comments young man , makes me wonder if you have ever worked in the trade :?:

Shame you dont like modern Tech .. i find it fascinateing and im afraid on a car is has to happen .. emissions have to be brought down and better tech is the only way to do that .

Back when i started there was no fault codes .. carbs and points / condensors etc etc .. if you had a fault you had to know were to start .. is it fuel or spark related .. thats the hunch side of it .. you kinda felt which way to go..

You could just test everything but that would take for ever so you went with your gut feeling.

I do the same today .. i " feel " what the car is doing .. i also read a job card .. same as a post here and get a feeling for what is likely to be the fault .

Descriptions of what the car is doing , noises .. at certain temps etc .. its all a massive help .. the more info the better .

Ok .. yes .. 928 wiring .. scary as hell and most mechanics will run a mile .. couple of images of the fuse board below .. its 2 feet long btw.

Its actually simple .. look at a wiring diagram .. i can figure out an entire system from these .. you just have to break it down into the bits you need for the fault you are working on .. early stuff is all switches , relays and good old 12 volts .. simples !!

Modern cars however .. 20-30 control units .. basically an office network .. they comunicate in binary on whats called a CAN bus system , think of a ring were messages get sent out from every control unit and the control unit thats needs that info takes it .. it ignores everything else .. M25 in rush hour but at 200 mph !

Latest is LIN bus .. master and slave so less messages and less control units talking .. the slaves only talk to the master .. the master decides if it wants to share the info.

Great idea but if i want to talk to a slave i cant .. i talk to the master .. it then tells me the slave info .. masters lie

This is all to do with weight saving and speed of data transfer ..

But it introduces a new problem ... SOFTWARE !!

Things will stop working due to corrupted sortware these days .. and i CANT see this !!

This is where understanding a complete system comes into it ..

Instinct .. is something not working due to a high resistant wire or is it software related .. and trust me the dam contol units wont tell me this .

When im teaching .. i always say .. understand a system then fault find .. if you have to go away for an hour and read up on it .. get your head around it then do just that ..

Stuff what the office says .. understand the system THEN fault find .

I cant say that enough .. you will struggle badly finding whast wrong if you dont know how something works .

The downside .. as you say .. lack of info .. Porsche dont like to give any info on software .. they wont explain it even to their own techs ..

Ive been on Porsche training cources were the instructors had had to try and back engineer systems to teach us .. Porsche dont even tell their instructors how things work at times !!!!

Porsche vision for the future .. log generated at OPC and sent to Porsche Germany .. German Techs then decide whats wrong and tell the UK guys what to replace .. OPC techs will one day be unit fitters and no more ..

this is already in the pipe line .

Is it fun though :?: hell yes .. 37 years in and doing a service is boreing as .. erm .. well a very boreing thing

To fault find something .. i can be on it 4 hours and untill i find the fault be it software or a tiny bad connection on a wiring plug buryed under half the carpets and panels in the car then im none the closer in a sense .. its not fixed untill i find that 2 min repair job that takes me hour after hour to find ...

Dam i love this job at times .. but there is also .. that lack of info job and im going around in circles ... poor info , not understanding a sytem totally and still having to fix it ... those are the bad days ..

Whats is amazeing though .. the amount of times ive gone home .. give up in a sense .. come in the next morning and solved it in 20 mins ...

The brain is a strange thing !!

I think this is one of my longer posts :floor:

deMort said:

very Asute comments young man , makes me wonder if you have ever worked in the trade :?:

Shame you dont like modern Tech .. i find it fascinateing and im afraid on a car is has to happen .. emissions have to be brought down and better tech is the only way to do that .

Back when i started there was no fault codes .. carbs and points / condensors etc etc .. if you had a fault you had to know were to start .. is it fuel or spark related .. thats the hunch side of it .. you kinda felt which way to go..

You could just test everything but that would take for ever so you went with your gut feeling.

I do the same today .. i " feel " what the car is doing .. i also read a job card .. same as a post here and get a feeling for what is likely to be the fault .

Descriptions of what the car is doing , noises .. at certain temps etc .. its all a massive help .. the more info the better .

Ok .. yes .. 928 wiring .. scary as hell and most mechanics will run a mile .. couple of images of the fuse board below .. its 2 feet long btw.

Its actually simple .. look at a wiring diagram .. i can figure out an entire system from these .. you just have to break it down into the bits you need for the fault you are working on .. early stuff is all switches , relays and good old 12 volts .. simples !!

Modern cars however .. 20-30 control units .. basically an office network .. they comunicate in binary on whats called a CAN bus system , think of a ring were messages get sent out from every control unit and the control unit thats needs that info takes it .. it ignores everything else .. M25 in rush hour but at 200 mph !

Latest is LIN bus .. master and slave so less messages and less control units talking .. the slaves only talk to the master .. the master decides if it wants to share the info.

Great idea but if i want to talk to a slave i cant .. i talk to the master .. it then tells me the slave info .. masters lie

This is all to do with weight saving and speed of data transfer ..

But it introduces a new problem ... SOFTWARE !!

Things will stop working due to corrupted sortware these days .. and i CANT see this !!

This is where understanding a complete system comes into it ..

Instinct .. is something not working due to a high resistant wire or is it software related .. and trust me the dam contol units wont tell me this .

When im teaching .. i always say .. understand a system then fault find .. if you have to go away for an hour and read up on it .. get your head around it then do just that ..

Stuff what the office says .. understand the system THEN fault find .

I cant say that enough .. you will struggle badly finding whast wrong if you dont know how something works .

The downside .. as you say .. lack of info .. Porsche dont like to give any info on software .. they wont explain it even to their own techs ..

Ive been on Porsche training cources were the instructors had had to try and back engineer systems to teach us .. Porsche dont even tell their instructors how things work at times !!!!

Porsche vision for the future .. log generated at OPC and sent to Porsche Germany .. German Techs then decide whats wrong and tell the UK guys what to replace .. OPC techs will one day be unit fitters and no more ..

this is already in the pipe line .

Is it fun though :?: hell yes .. 37 years in and doing a service is boreing as .. erm .. well a very boreing thing

To fault find something .. i can be on it 4 hours and untill i find the fault be it software or a tiny bad connection on a wiring plug buryed under half the carpets and panels in the car then im none the closer in a sense .. its not fixed untill i find that 2 min repair job that takes me hour after hour to find ...

Dam i love this job at times .. but there is also .. that lack of info job and im going around in circles ... poor info , not understanding a sytem totally and still having to fix it ... those are the bad days ..

Whats is amazeing though .. the amount of times ive gone home .. give up in a sense .. come in the next morning and solved it in 20 mins ...

The brain is a strange thing !!

I think this is one of my longer posts :floor:

Click to expand...

You have just described my day to a T :thumbs: :mrgreen:

Apologies to Swampy, for taking this topic just a tad off track. I do hope your fault is resolved, though I suspect the thinking at the dealer will be leave it to see if it develops in use from intermittent to something a tad more constant, and thus simpler to trace and rectify.

I will try to keep this short but it seems impolite not to try to respond to DeMort..?

I have had 50 years in employment bashing things with hammers to make them work, and have since retired, so a bit ahead of you in the electro/mechanical game... though retired for a number of years now to become a fully signed up grumpy old man..and still dabbling round the edges all be it with a lighter hammer...(-: Though in truth I accept time does not stand still, it`s just that my time of being useful is past...Shrug.

I type way too much for anyone to read it all, though elsewhere on this forum I typed of a situation with a McLaren F1 the proclaimed first car with the ability to connect to the factory directly with it`s own built in dial up modem... Space age or what..? Well it was a few years back.. Fault light showed up while the car was touring Scotland, I met the Tec from Woking who flew to Inverness hired a car and drove down to the car at FT William to reset the light. When I queried him as to why he did not carry out the re-set from the factory... he sited systems security... or in my line of thought, protection of intellectual copyright. Amazing.. NOT.. that companies would go to that level of cost rather than connect up via one of the facilities they used to identify the car as high tec... (-:

Yup, I have repaired a couple of wiring faults on a 928 which was a friends car and they were on that very fuse board.. (-: I could ramble on and on but will bale out of this thread for fear of mucking it up.. Happy to chat in the members lounge as opposed to diverting the subject line of the thread.. Apologies gain Swampy.

Ive asked that this be split into another thread as i would like to continue it .

@ Matt .. anyone that has to diagnose things will work this way so you and me are not unusual .. but im afraid i have and do see the guys that jump from one thing to another rather than following the set way of fault finding ...

That starts with is there 12 volts in the battery :floor:

Actually we probably are a bit unusual thinking about it .. im the only one at my place that fault finds on a daily basis and i was 1 of 2 that did it at an OPC .. thats out of 7 mechs at the time .

@ Luddite

I think you did a little more than " bash things with hammers " young man .. your comments prove that and you certainly have an in depth knowledge of the " way the system works ".

Your never too old in this game .. you just fall behind on the new stuff .. the old stuff .. is still the same though .

A permanent fault is obviously easier to find .. not much point me testing a bunch of wires if the fault isnt there as i cant prove anything .. But ..

If i know how a system works in depth then i can logically work out the most obvious item that is causeing the fault .. if i dont know how a system works then i say .. n.f.f and customer to monitor .. a cop out basically untill the fault becomes permanent.

Downside is i may not be correct .. so whats the best way forward .. either basically but that again depends on how confident the mechanic is .

Educated guess is the proffesional title i beleve


The McLaren fault .. it would indeed be easy to remote reset the fault code so a bit strange he didnt .. im not sure of the secutity as remote or on hand hes the one with the laptop doing it and he says who watches him .. my guess would be more due to if the fault came back he would investigate further perhaps .. :dont know:

It is the way of the future though .. cars can already talk to Porsche about problems via the internet and Porsche can contact a customer to say take it to a workshop as we feel there is a problem even before the customer has noticed anything ... lets just say thats current / in the future

Bit scary when you think about it .. Porsche can monitor your car .. they can also see where it goes .. how fast .. etc etc .. big brother almost .. 1984 .

Customers can also do the same .. a mechanic can be on road test and before he gets back the cutomer can phone the opc and say .. he was speeding !!!

928 fuse board problem .. a man after my own heart .. great fun .. its like the nervous system .. everything happens through that point ... you have a fault .. start there !!

Im currently working on a 924 with electrical faults .. many .. and not one is current .. ive found a small hole in the bodywork right above the fuse board .. water ingress .. :?:

Luddite said:

Apologies to Swampy, for taking this topic just a tad off track. I do hope your fault is resolved, though I suspect the thinking at the dealer will be leave it to see if it develops in use from intermittent to something a tad more constant, and thus simpler to trace and rectify.

I will try to keep this short but it seems impolite not to try to respond to DeMort..?

I have had 50 years in employment bashing things with hammers to make them work, and have since retired, so a bit ahead of you in the electro/mechanical game... though retired for a number of years now to become a fully signed up grumpy old man..and still dabbling round the edges all be it with a lighter hammer...(-: Though in truth I accept time does not stand still, it`s just that my time of being useful is past...Shrug.

I type way too much for anyone to read it all, though elsewhere on this forum I typed of a situation with a McLaren F1 the proclaimed first car with the ability to connect to the factory directly with it`s own built in dial up modem... Space age or what..? Well it was a few years back.. Fault light showed up while the car was touring Scotland, I met the Tec from Woking who flew to Inverness hired a car and drove down to the car at FT William to reset the light. When I queried him as to why he did not carry out the re-set from the factory... he sited systems security... or in my line of thought, protection of intellectual copyright. Amazing.. NOT.. that companies would go to that level of cost rather than connect up via one of the facilities they used to identify the car as high tec... (-:

Yup, I have repaired a couple of wiring faults on a 928 which was a friends car and they were on that very fuse board.. (-: I could ramble on and on but will bale out of this thread for fear of mucking it up.. Happy to chat in the members lounge as opposed to diverting the subject line of the thread.. Apologies gain Swampy.

Click to expand...

No need to apologize Luddite, it all makes good reading

Swamps

Thanks Swamps, though if anyone is looking for air bag answers at some future time using a search facility, having to wade through my rambling on about this that`n the other might be a tad frustrating..

I am more than happy to share my outdated thinking with anyone who has interest, though don`t want to muck up any threads with it.

You ramble as much as you like .. thats what we are here for .. i learn as much from you guys as you learn from me i feel .

you would be suprised to learn some comment even if off topic helps someone else here .. as said its all good reading !

I see your request has been granted by the powers that be Mr DeMort and this thread has been moved to a more suitable location.

Where to start..hmm. ????? DeMort, you asked if I had ever been in "the trade" .... the answer to that specific question is no, though if you have any interest in part of my involvement with machinery and technology you could find out a tad more via my entry to this forum in the... Members Lounge.... under "Newbie but with previous Porsche history" or some-such title. Admittedly it is a rather lengthy thread...

Mr DeMort, relating to your question above I have been fortunate to have relatively intimate knowledge of many "trades" and feel I have benefited greatly from the experiences I was privileged to share around tradesmen. That I was involved in so many areas and over a timespan of 50 years relative to paid employment, equates to a reasonable breadth of observation that may have value to someone somewhere.. Though the young know it ALL already....? (-: Just a bit of FUN, but I have often typed this little observation to cover that line of thought..

When I was 15 years old I thought my father a fool..... now that I am 21 I am amazed at what he has learned in 6 years... (-:

I am more than happy to share what little I know in the hope of learning from others, though being ..err.. "mature" I struggle with memory just a tad.

If I might START.. with Matt Sebrook`s entry where he typed... " You have just described my day to a T"

Matt was responding to the long entry on DeMort`s thinking on his modus operandi when faced with some fault or other on which he (DeMort) may have LIMITED information to aid the repair process..? Thus it seems like DeMort, Matt and no doubt countless others in a variety of electro/mechanically related trades, may be experiencing increasing LIMITATIONS relative to the ability to repair just about EVERYTHING, from a toaster to a missile and all else in between.. Technological "advance" is absolutely amazing and gaining exponential speed in the process, when it is all working though frustrating when it is not..? It is indeed unfortunate when the toast gets burnt, but an errant missile can be a bit more of an issue perhaps..? To quote the line from movie Dark Star... "I am a bomb therefore I am".... ROFL..

What about, " I am a Porsche and thus far more intelligent than you".. ? Yeah taking things a bit far there, but I do wonder how many decisions your Porsche makes over which you have no control, or at best limited control...?

What about the poor mechanic who is tasked with fixing it when it goes wrong..hmm ? Well I guess as in most electro-mechanical situations there may exist mechanics and mechanics, or is it that they like many trades have all been elevated to the status technicians..? (-: But wait, there are those who may be termed as Hi Tecs, who as the result of perhaps having more enquiring minds than the mechanics, fitters and general component changers, are perhaps allowed more access to INFORMATION on how to repair the more high tec stuff..? Perhaps the reality is that there is a NEED to have hands-on types, for even with all the technology available IF there is a poor connection equating to a high resistance or break in a circuit the "intelligence" can not fix it and thus still needs a pair of hands with some measure of brain power attached, though for the sake of say..err.. PROFIT, it seems wisest to protect our control stratedgy from plagiarism of any kind, thus keeping tight control over any such information would seem to be a priority...?

Sure our product "depends" upon the input of tecs to repair it quickly and simply to create or maintain it`s rep for quality and reliability, but there must be a balance set to also protect our INTELLECTUAL INVESTMENT. It is NOT as if our control stratedgy is to be kept as secret as possible because there is any programming designed within it to circumvent regulation, or convince a gullible public/customer that our machines are more economical or less polluting than they are, or any such thing....? (-: For to get involved in activity like that would be....err... A pity, more so if we were found out by enquiring tecs who just wanted to try to understand as much as possible relative to the actual DESIGN FUNCTION SPECIFICATION of our control strategy...hmm...?

Still with me guys... or am I typing to just pass the time in retirement... (-:

In terms of digital technology, somewhere between toasters and missiles, aircraft can be found...? I suspect those tecs may get a bit more insight/training as to the control strategy though the end users..? The pilots, perhaps considerably less so, which seems reasonable given the amount of technology involved and very necessary ultra rapidity of decision making processes in some aircraft programming that are well beyond human capability and yet required to keep them flying...hmm..?

Perhaps Porsche drivers and pilots have something in common then..? (-: If you want to drive like a nutter, you can switch off this that and the other software.... or depend upon the same software to keep it out of the hedges when trying to lay down MAX horsepower on some slimy surface......When it goes wrong as the result of the Porsche drivers input or some glitch in the software, hopefully there is no trauma so associated... take it to the garage and have it fixed.... perhaps... nff.. or no fault found on an intermittent fault on a road going vehicle can be as the result of driver error/owner input that confused programming to some extent... how to trace that...? Well there is the black box equivalent.. Hmm.

I tend to lack confidence so am likely to never say never relative to any fault. In connecting an external electrical device to what is a rather complex piece of equipment may just have potential to introduce a wave pattern that disrupts the expectations of the on board systems...? Generally one would expect the battery to act as a sort of smoothing device in terms of electronic/digital circuitry..... but....? It seems some digital electronic systems can learn and adapt dependant on input.... perhaps they can also adopt an issue they should not..?

TRAINING be that tecs or end users is not always as we might wish it to be..? If you have read this far then you might have grasped a measure of that as being my line of thought..The human can fail the system as well as the system failing the human, it can be a double edge sword on occasion....It seems too many fault codes, or alarms can end up creating confusion more so if those tasked with interpreting them do not have adequate training to handle the prevailing situation, nff might be a reasonable out for a tec in regard to an intermittent fault

However taking a few hundred folk to their end as the result of "pilot" error derived perhaps from information overload and a lack of REAL knowledge of the layout of priorities relative to INPUT to flight systems, would hint at training deficiencies, given at least two "trained" humans had time to consider the options they were presented with in one particular set of unfortunate circumstances, a third and senior only came on scene when it was too late .... very sad indeed.

I wonder how many car accidents might be down to technology and it`s programmers confidence that they have got it right.... Any idea of how many folk have been caught out by technological innovation seemingly as simple as auto stop facility designed as a pollution cutting/ fuel saving few lines of programming causing confusion... you might be surprised..?

In terms of hard wired circuitry it was simpler to diagnose faults if you had a wiring diagram that included all the switching actions allowing a tec to follow the circuitry wire by wire switch by switching action to resolve the issue... In time the same faults could turn up time and again on different machinery perhaps caused by poor quality components or similar, thus the wiring diagrams became unnecessary for those who had experienced the similar fault on other machines and could go straight to the cause of the fault and effect a repair...I suspect the same situation exists with digitally controlled equipment where something as simple as a connection known to fail under certain circumstances can be found and repaired quickly...? Factory recalls make interesting reading, should you wish to investigate further..?

Poor quality equipment... ! Well now have you never seen the lookie lookie guys on a holiday beach selling genuine Rolex...? It would seem that you may be able to buy equally genuine parts at a fraction of the cost for just about everything...and if you add any of that to the mix relative to failure and fault finding....!!!!

I guess my Luddite tendencies tend to show through when folk such as tec`s abilities are seemingly ever more downgraded on a need to know basis, and that the level at which they could strip repair and replace components is considerably reduced with the passage of time, in that the construction of equipment is such that it is designed from the outset to be assembled by robots, thus it clicks or is glued together, inhibiting to some degree a reversal of that process where repair in required.... Resulting in requirements to purchase ever larger repair componentry..?

An example... a Range Rover Evoque circular door speaker grill.... seems like a pretty poor quality plastic item that can break with relative ease perhaps 150mm in diameter, replacement cost... Well if you thought £20 from RR parts dept, you would have been wrong, last time I looked you had to buy the whole door card, which comes in circa £900... !!!

I remember large fire engine with sliding window on the rather large door it had a right angle stainless steel hinged clip fixed to the door that could be flipped up against the edge of the sliding window to stop it from sliding.... the clip was lost, don`t ask me why.... imagine a cost of repair if you will.....? Nah... you can not buy the clip, you need to buy the whole door.. Yeah it can all get ridiculous indeed.. Might a tec just fashion a simple clip arrangement similar to the ORIGINAL manufacturers part... any risk involved in that...? Hmm.

Potentially skilled folk being deprived of the ability to be trained to understand and repair equipment in favour of ease of assembly for robotic processes, or to retain intellectual control for whatever reason... apprenticeships in the bin unless there are financial incentives...it does seem that we are at a stage where in some circumstances we are aiding the machines as opposed to the other way round.... Orwellian or what..? Next thing you know all your money will just be a series of digital data... how easy is that to steal...? Yup it is indeed a ever evolving world and I am an old Luddite feeling fortunate to have lived when I have...

DeMort all this as the result of you thinking it is a shame that I do not like modern technology.... (-: Truth is there is NO chance of avoiding it and it has been that way for so many years in so much of everything we may do and has provided great advantage, BUT...Hmm ????? As yet another kite is grounded world wide and why.... hmm, very sad indeed.

Yup have had involvement with OBD II, worked with token ring networks, BMS systems with outstations and equipment spread over acres of buildings and others on rather large and heavy machinery linking GUI to nodes, and high current switching devices to operational actions, high voltage generation, wiring, switching, alarm raising of many types and systems with miles of interconnecting cabling and comms making up circuits all of which required a BIG hammer on occasion, had my day and enjoyed most of it and survived... You can`t ask for more than that... except a pension and a Porsche perhaps....? :floor:

Sorry for not replying last night .. im afraid i try to answer a lot of questions and only have 2 hours per night in which to do it ..

Also this section of the forum is new to me .. i never scroll down this far as i tend to stop after the car sections !

I asked that the thread be split as its an important but seperate area from the original post .. which is on going.

Young man !! i thought i could write a long post but this has to be the biggest ive ever seen

Im afraid as above i dont read the newbie section or pretty much any thread thats not related to a problem hence ive not read you previous posts but i get the gist of it .. you have worked at different but sometimes similar trades which would give you a very good understanding of Car technoligy .

Im afraid that both Matt and myself do not work for dealerships .. i used to but no longer have access to the information .. we have other sources and of cource what we have learnt .. basically its experience and methodology we use .. there is a set procecess with fault finding ..

logical , thorough .. understand the system and double check each item as tested .. tick it off on a sheet then move on .. what you are left with , even if you can not prove it is the most obvious fault .

You cant prove a control unit is faulty .. you have to prove everthing else is ok basically .

We used to just have 12 volt systems so pretty easy .. new cars with control units and we have to factor in software faults .. obviously we cant see that so we work as above to diagnose .

Is it a bad thing .. i think not , cars are more complicated as there are more electrical systems .. more things like heated seats , memory seats , auto dipping mirrors let alone the engine systems that have to hit tighter and tighter emission limits .. control units are there for a good reason let alone the speed factor of comunication.

PSM .. the car is trying to save you , even when switched off its there in the back ground but is far less active .. with fly by wire and abs the car can control the throttle and any part of the brakes it wants to .. in the event of the car going out of control its your last liner of defence .. hence it needs high speed inputs from engine and brakeing control units .. a 12 volt cable just doesnt cut it im afaid ..

So basically technoligy saves more lives .

These days we tend to split the mechanics up in a workshop .. some are more suited to service work , some of engine rebuilds and some for diagnostics .. you basically have to have a flair for it i feel.

Im not an engine man .. im no good and i hate them .. im also on the little side so gearbox out and i need help .. plus side .. i get almost every fault that comes through the door .. i make descissions that cost £1k or more in parts every day .. and i have to be right every time .. do i get thanked .. hell no .. its expected .. try making a judgement call on a £2.5 k part that i couldn,t prove but had to say this is what is needed .. that was a long weekend till i got the part and it fixed the fault i can tell you !!

no one mechanic can do everything these days .. those days are long gone as the cars are simply to complicated to understand every part of the job and the car going back 30 years .

When i started i was a Mechanic .. these days its all about Technicians .. my dentist has a Dental technician .. slight diffference between the two .. i consider myself to be closer to the dentist hence im a car mechanic .

When i started i did 5 years of Tech to become a mechanic .. 3 years and i was quailfied as one but another 2 years on specialiseing .. 5 years basically ... our appentise atm .. 2 years and hes qualified ..

makes one wonder are the kids today supper clever and im just thick as it took me 5 years .. or are the exams dumbed down these days .. :?:

Luddite .. someone who is opposed to new technoligy .. i would think that you are not opposed by it as such .. maybe more depressed and can see where it will lead .. end result being A.I .. self aware ?? worrying .

Your choice of name there .. btw .. mine means of death .. from death .. it has meaning for me but if someone new what it stood for they would assume something sinister .. which its not .. Luddite would get people thinking the literal meaning the same way ... i did.

Please . if replying .. not such a long post .. i did my best to read through it and understand .. but bear in mind .. im a mechanic that started work in 1981 .. in those days the kids with little inteligence left school to do that job .. im a mechanic .. im no academic im afraid .. you have a problem with your car .. ill tell you what it is .. a long post of inteligent questions and thinking .. im out of my depth im afraid .. sorry .

Which is easy to prove .. just look at the spelling mistakes

My dear deMort, no need to apologise to the likes of me.... You are worth your weight in gold to this community and no doubt your customers, Me? I`m just an old Luddite howling at the moon and on occasion expounding theories...
Spelling mistakes... jeez, just look at my attempts at punctuation and were it not for the spell checker, my gibberish would be entirely illegible.. I left school at age 15 with a BPA... boot print in the afterburner..(-:

Strange as it may seem I have been involved with fault finding utilising a code reader on a couple of cars, one was an MB diesel.... I was helping a pal with the fault on his low mileage car on which he had replaced a couple of rubber hoses and perhaps the fuel filter..... when I got there it would not start... The fuel pumping was done in two stages with two engine driven mechanical pumps the lift pump feeding the high pressure pump... He had been cranking it for a while to the extent his next door neighbour, a garage owning mechanic appeared on the scene and provided a code reader which he connected up, but seemed incompatible with the version of software in the Merc, so off he went to his garage to get his Snap On code reader... While my pal cranked the engine over I had a look around the area of the pumps which has a clear hard plastic tube fitted between them and noted a bubble in the fuel moving from the low pressure pump and up into the high pressure pump and when the cranking stopped after a few seconds the bubble returned in the opposite direction.... Logically (?) I suggested this might be part of the problem...The Mechanic returned with the reader... Fault code indicated low fuel rail pressure... When I drew his attention to the bubble, he said "they all do that".... hmm.

The Mechanic phoned a pal who is a diesel mechanic and he suggested that there may be a leaking injector and suggested having them pressure tested... Hard to diagnose faults over the phone...

I thought if an injector was leaking there would be signs of diesel in the oil so went looking for a dipstick to feel the oil.... No such thing on this engine..hmm. So injectors stripped out and looking very clean and taken to be tested... NFF... injectors refitted by my pal, no mechanic around... my bubble theory was now deemed worthy of consideration...perhaps more so as the cost of injector tests did not resolve anything other than prove the injectors were just fine.

We stripped the pumps... jeez those are tiny springs and valves in the pump and found a TINY piece of black grit or something on the white rag we put on the bench to catch any errant springs etc did it come out of the pump or not.... Hmm...? if so that may just have caused an issue... we build the pump back up and before connecting the plastic pipe I looked at the interconnecting rubber pipe which had a small nick out of it`s internal bore probably caused by fitting it to the plastic pipe....perhaps that might explain the tiny bit of black stuff...hmm.

Cranked the engine saw a bubble it took a while to move between the pumps.... still no start, despondent pal, but the bubble did not return, which suggested to me that it had perhaps been a non return valve issue.... a few more cranks to bleed the fuel rail... close the bleed screw and tried again and it fired up... happy pal, job done..

Another code reader attempt was on a Manaro/Corvette V8 we fitted in a Triumph Slag ..err.. I mean Stag, that drove great till wider throttle openings caused it to accelerate like a train then cut out and go into limp mode on restart..... but this mail is increasing in length, with nothing Porsche related...So best cut it here... oops!

Thanks for taking the time to reply deMort... much appreciated, I learn a great deal from your input.... though at my age I have trouble remembering it.... Sigh

:floor: trust me im younger .. i often get asked at work .. you remember that car you worked on a couple of weeks back ... i look at them blankly .. that one with such and such .. another blank look ..

Finally it dawns on them .. i have no idea what car .. i dont care as ive already forgotten what i worked on yesterday .. its just another car .. if nothing different about it then its yet another car over 15 years lol .

Self preservation is what i call it .. you remember every car .. you remember every job .. you start to worry .. did i tighten that enough .. did i do this .. etc etc ..

i forget as i just do my job .. self preservation

You have asked some thought provokeing questions , im afraid im not best placed to answer as i get a desription of a fault and then resapond .. basically i answer a question ..

i have enjoyed reading your posts though .

diesel .. an air bublle if you can see it .. thats not right on a sealed system .

At the end of the day .. if anyone knows how a system works then you can fix the faults on said system.

Stag .. hmm .. not a big fan .. i tryed changeing a water pump on one .. hmm ..

we are both in agreement though .. we forget things

It pleases me greatly that you or indeed anyone might have found something enjoyable or interesting while reading anything I post deMort.

I sensed what I thought was a measure of frustration in your repair processes from time to time, perhaps brought about by not having access to quite as much information as you would like relative to the design and function of whatever bit of kit you were working on.... ?

If my thinking was in any way accurate then that is the sort of limitations I worked with for a great many years. In the rather long contribution above, I tried to condense an explanation as to why I think as I do, I suspect you are not the only tec facing a similar scenario on a day to day basis, and I understand well the feeling of triumph over adversity when despite the barriers you have to contend with, you can still return a machine or system back into service, that is what keeps so many tecs going.. (-:

Even back in the seventies an auto electrical wiring diagram could be less than helpful, sure it would show the circuit lay out, each wire`s colour designated even the straight through plugs and sockets shown as it passed through the system from dynamo/alternator, to battery to switch to whatever device was being controlled, and if you were lucky the internals of the switch might be shown, but often a switch could be shown as an empty circle, which was no real problem if the switching action was limited to on or off, thus simple enough to work through, even with multifunction switches, knowing the ACTUAL operation of the circuit (it`s design and function) you could work out where the problem lay... BUT by the time electronic control systems were utilised and perhaps any number of wires entered a control unit displayed on the diagram as empty box... It all became a tad frustrating.... If one ads a few more years, digitisation and miniaturisation, trying to mentally construct the... design and function.... of a faulty circuit or device in order that you can work back from the fault to effect a repair, has it`s share of frustrations, more so when with a reasonable amount of INFORMATION available to the tec, the whole repair process could be simplified and made far more efficient..costing the end user less in the way of down time and cash.. hmm.

Diesel air bubble.... It seemed reasonable for it to exist given the system had been broken into to replace pipe connectors, and perhaps a filter, though it was it`s movement within the see through section of pipe when the starter was engaged, and then stopped, that piqued my interest..

A Stag is not one of my favourites either, though my time replacing the water pump on a pals 928, as I typed of elsewhere on this forum, was not my idea of fun either.. I rebuilt rather a LOT of the bodywork on a friends totally rotten Triumph Snag some years back, that was the start of the end for me I think even the glass was rusted...)-: Definitely not one of my favourite machines, though the tin worms seem to love em..

The Manaro engined Stag custom that my another pal created was unusually almost rust free at the outset, access to a software reader for that engine was not simple given it`s rarity. The reason it went into limp mode was that on wider throttle openings the throttle plate would catch on the side of the modified tube in which it was housed causing it to stick slightly thus the software sensed the throttle plate was no longer synchronised with the throttle pedal input... an easy fix once discovered.

Fitting a Lexus V8 into a custom truck.... that was a whole different software story, that does not end well.. :frustrated:

When i worked at Volvo many years ago we had books of wiring diagrams , these had seperate pages showing the current direction .. very easy to use and diagnose problems .. you didnt need to be an electrician.

Porsche dont do it that way .. you just get a diagram but thats fine i can follow that and work out the fault but its no longer any mechanic can fix it .. you need to be able to understand the diagram.

Ok .. but thats the old stuff so say upto 1997 ..

Control units started getting fitted in 1998 on the 996/986 .. same wiring diagrams as for the older cars but just a box that the wires go into .. you dont know what happens in that box and you are not trained on the software.

You are trained what inputs and outputs but the box has a predefined map in it for what ever system its on and so you dont actually know whats going on .

You can test for a feed in .. and a feed out .. if no out feed then we could say .. new box needed .

BUT .. today its far more complicated .. the inputs and outputs are binary messages .. i cant see these , i cant test for them so i have to try and work out how every system actually works ..

That is frustraitreing .. there is actually equipment out there that would help .. its called a Canalyser .. a laptop you cut into the system and you can see the messages .. no garage including Porsche OPC have these though.

They also dont help with the internal software problems ..

Your PC at home locks up .. you turn it off then back on .. i do the same on new car control units and it often fixes things.

Software can be a pain .. but also fun .. i do love a challenge .

The downside to all of this is the average mechanic wont have a clue so its now moved onto a garage needs an auto electrician .. but who is also a normal mechanic for when there is routine work to do .. not so many people like that around when we are talking about a niche market like Porsche .

We have both experienced similar problems over the years so you can see what im up against as you have been there many times i expect ..

But the feeling of actually finding that fault is not something i can easily describe .. its what keeps me fixing cars after 37 years i guess

Great that software reliability seems to have improved in terms of it`s security relative to RF and other outside influences and that devices attached to it seem to have become a tad more robust also, though while the control systems have become more intelligent they also seem to have been designed and configured to further exclude access and repair by mere humans, unless they have the appropriate training and kit with which to interrogate the system, kit which these days manufacturers seem ever more to wish to hold close to their headquarters whenever possible... ?

Manufacturers "special tools" were perhaps the first attempt at introducing a measure of control over the repair process..? IMS issues and the likes are nothing new in terms of a pox on a brand. In the early seventies an even larger manufacturer than Porsche introduced a new overhead cam engine on which the cams failed regularly, nay, far too regularly, and such was the design that the cam could not be removed without taking the head off, which required a "special tool" to fit the head bolts. Of course it did not take long before the special tool was re-manufactured and readily available to the DIY brigade..

The introduction of electronics to vehicle systems, was perhaps another opportunity to exert a measure of "special tool" control, and as electronics advanced to become digital there was even more opportunity for control over repair when ECUs became part of the system. As before it was not too long before OBD readers became generally available and the costs reduced to the extent that the DIY folks once again had access to interrogating and repairing their own vehicles, it seems to be all just part of the inevitable evolution in technology....?

Perhaps it may not be too long before Canalysers become available to DIY types as that technology leaks out is copied and re-manufactured by code reader pirates.. (-:

KNOWLEDGE IS POWER....but there ever tends to be those who through means fair or foul want their share of that, and even more fortunately there will be those who care to share with anybody.... Be grateful for the internet and Youtube......be very grateful... (-:

In Porsche terms it seems logical that they may take ever more steps to utilise whatever technology might be available to protect their intellectual investment if indeed they may restrict access to the design function specification of their digital control strategies..?

It seems logical that there is perhaps a possible "leakage" in terms of KNOWLEDGE and the associated control structure as is normal with human activity when those trained in any specialist systems perhaps seek to advantage themselves by setting up some sort of alternative repair structure, undercutting the original creator of the technology which may encourage further measures relative to increasing security by the original creator thereof...? Quite where that is currently or where it will end up over any period of time is quite beyond my ability to comprehend...

That you are enjoying repairing Porsche cars and sharing your knowledge on here is just GREAT deMort, Long may that last. I suspect you are a very important link in terms of reducing frustration with the brand for those who might otherwise give up on Porsche in frustration, thus Porsche themselves may even value your input in terms of assisting with customer relations deMort, long may that continue.. :worship: