Colin, You're my hero! Cheers, Owen. ----- Original Message ----- From: e-mail colin.jones5857 To: mogtalk2 Sent: Friday, May 11, 2012 3:37 PM Subject: Re: [mogtalk2] Miscellany
Hi Owen No thanks required at all, just the thought of another worry gone is thanks enough ;-). I did not come up with all these fixes alone either, many are the work of several of us spanner jugglers working together being real nerds sending emails in the night about codes and misfires and to be honest just plain and simple detective work. Just to help you sleep here is the story of the EVAP diagnostics and conclusion. On holiday in France with Christopher BK, Richard Rebain and wives. I arrived last at the Gite and JUST after filling up, that's a misnomer as the petrol attendant filled the car and was so busy admiring he washed the back of the car with petrol, it was overflowing from the filler neck! (don't think the village had even heard of blow back arresters on the pumps!). Anyway after throwing his screen wash bucket of water over the rear of the car I drove off, no problem. Next morning, off for a drive, 3 miles down the road and the car sputtered coughed and almost stalled.....then it cleared and was fine for 30 seconds and did it again....5 or 6 times so I returned to the Gite to think.......(and panic). OK, the feeling was just like someone pulling out the choke and there was a strong petrol smell, it was a soft chop (electrical faults feel hard, fuel feels soft) Could not see anything of course so started to think where excess fuel could come from. On a whim I unplugged the hose from the EVAP purge valve and it was full of fuel. I shook out what I could and started the car. Stood watching it run then hunt and cut then run etc. etc. it was clear it was cyclical. I made a test lamp from a spare bulb and wire and bridged the electrical plug on the purge valve and started the engine, the bulb lit when the purge valve was energised and a couple of seconds later the car spluttered,the bulb went out and again after 3-5 seconds the car cleared. I then had another think, syphoned out one gallon to lower the fuel level, had a terrible job getting the EVAP canister out and emptied another pint of fuel out of it, left it to dry in the sun, blew through the purge lines and reassembled. Problem gone, it only ever happened once more after I had overfilled the car by mistake with a fuel can and then I left it running to purge itself. Fault finding is just gathering evidence and understanding the systems. Lots of fault codes are not actual faults its just that the programmers set parameters and if the system steps outside of allowed values the code is stored. Later systems are far more sophisticated and have a priority learn function, that is if its a none safety related code (and even some safety like the BMW ABS low voltage codes) if the system sees 5 cycles of no more code found it wipes the codes and puts out the warning light. Some codes (like the multiple misfire) is used to cover a multitude of sins as just about everything we have discussed as a possibility for your car would look to the ECU as if its been caused by a misfire, hence the code stored. I don't always know the answers but am always happy to help or at least try to, these systems are really good you know, its just that we did not have fault codes on good old carbs and coil ignition systems or we would have had even more codes stored ;-). BR Colin On 11 May 2012 11:58, Owen Jenkins <[email protected]> wrote: Colin, You are a shining star and an example to us all ! One thing that seems to bring it on is NEARLY stalling. That would be totally consistent with your explanation. Full marks, A*. Go to the top of the class. For many years I have sought and failed to find the answer. Now I shall sleep easy in my bed knowing that I can, indeed, ignore it. Many, many thanks, Owen. ----- Original Message ----- From: e-mail colin.jones5857 To: mogtalk2 Sent: Friday, May 11, 2012 7:08 AM Subject: Re: [mogtalk2] Miscellany Owen That's a rouge 'Multiple Misfire' code used on the GEMS system, ignore it. Its stored when the system detects a misfire (measured as a sudden change in rotational speed). Tn Tops have a 'mass accelerometer' that measure he vertical movement of the vehicle (this bit is mega boring and most don't believe it anyway) imagine a rotating engine, pistons going up and down.....hit a bump and the piston speed relative to the block alters, the maths are boggling so car manufacturers fit these mass accelerometer (sometime on the bulkhead (Volvo) or sometimes part of the ECU (Bosch Motronic). Because of the way a Morgan likes to spend as much time in the air as on the ground the mass accelerometers (like the knock sensors) are not fitted. This is ONE of the factors that cause the code to be stored. A software fix was supposed to solve this but seemed not to, plus the system is so sensitive if it detects a reverse signal from the crankshaft sensor (engine running backwards) it stores the only code it can, a multiple misfire.....of course the engine does not run backwards but when you switch off if a cylinder is coming up to TDC on compression it has been known to kick back a few degrees and that's enough to trigger the code, this is ANOTHER reason for the rouge code. Finally the other well known one is the advanced EVAP system that is on the GEMS cars, it has a vent tank for the fuel tank and it is vented to the inlet manifold via a 'Purge Valve' which opens under certain conditions (normally just after engine warms up). If you overfill the tank fuel bleeds into the vent tank, the purge valve opens and not only fumes but fuel is drawn into the inlet manifold/plenum chamber. the system tries to adapt when the Lambda sensors see a rich mixture, cant as its outside of the adaptive window value max setting and so thinks there must be a misfire (plugs etc. not firing) so stores the only code its been given which is 'multiple misfire'. To say the factory is unaware of this is not exactly correct, maybe they have forgotten, I went to see Mark Baldwin (had an appointment) back in 2002 when I had this problem and traced it on my car, it was at the request of my Dealer....Mr. Baldwin failed to keep the appointment. I then wrote a 3,000 word test and rectification note for the MMC and sent it to the factory, nothing was ever sent to the dealers that I know of. David Poole wrote the definitive guide to GEMS and several of us proof read it and suggested amendments and it really is the 'bible' for GEMS, again it was offered to MMC and the Dealerships and nothing was taken up so it sits on GOMOG for everyone to access. The information is out there Owen and its been tried to get it to the dealers. BR Colin On 10 May 2012 18:15, Owen Jenkins <[email protected]> wrote: Tim, I like the idea of what you are saying. I have a fault code reader/cancelling device. It cost a lot more than £30, but that's by the by. I bought it from Halford's. 'Nuff said. Now, to demonstrate to me that what you say is true, tell me what this fault code means: P.1316; and how I cure the fault. It's one I get often from my 4.0 litre, Land Rover V-8 powered, 2003 +8. If you can tell me, you can also tell the MMC - they don't know, nor do any of the dealers I've taken it to. Nor does the AA. I just cancel the code and carry on as before. Nothing seems to happen except that it occurs again, sooner or later. I gather Rover used to charge about £5 grand for their Testbook set-up. I'm not prepared to spend that on diagnostic equipment. Owen. ----- Original Message ----- From: Tim Harris To: mogtalk2 Sent: Thursday, May 10, 2012 5:52 PM Subject: Re: [mogtalk2] Miscellany On 10 May 2012 10:33, Chas. <[email protected]> wrote: Of course on the technical front there is much less you can do at home with modern electronics than you could with points and tappets. Sadly, this myth has been well and truly sold to many people, who honestly believe that you can't work with modern cars at home. Routine servicing is much easier than it used to be, spark plugs only have to be changed once in a blue moon, tappets, never need attention, all you really have to do is change the oil and check the fluids - and yet strangely the costs we get charged by the dealer are vastly higher than ever they used to be. Cheapest entry point is 30 quid or so, which buys a code reader with which you can interpret any stored fault codes and clear them (a process which a dealer would charge 70 quid plus for). Plug the reader into the OBDII socket, download the codes, look up what they mean, fix the offending part. Perfect for identifying and cleaning or replacing a dirty MAF sensor or similar. If you want to spend a bit more money, then a couple of hundred quid on a laptop, a copy of the relevant software (e.g. Rovacom for a GEMS +8) and you can furtle to your heart's content, really getting to grips with what your engine's up to. If you want to get properly ambitious, then you can buy a complete replacement ECU from someone like Omex (who supply MMC), Emerald, or MBE, and completely remap and reprogram your entire performance envelope. And if you want to go completely OTT, you can even build you own engine management system from scratch with Megasquirt. I fully understand that messing about with one's engine is not everyone's cup of tea - and fair enough, I wouldn't try to convince anyone to do stuff they don't want to, but I would hate to think there are people out there who think 'I wish I could work on my modern Mog like I used to with my old one". It's a different set of skills, sure, but certainly not beyond an average enthusiast mechanic. I reckon that adjusting one's fuelling map with a laptop is a heck of a lot more straightforward than trying to understand the complexities of twin DCOEs. Tim View posts on The Mail Archive http://www.mail-archive.com/[email protected]/ Modify Your Subscription View posts on The Mail Archive http://www.mail-archive.com/[email protected]/ Modify Your Subscription No virus found in this message. 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