| Author | Message | ||
     John Shostrom Experienced User Username: silvawraith2 Post Number: 30 Registered: 4-2005 |
First off, a very Happy New Year to all of you. Right, that's done -- now let's talk about our cars! On Christmas Eve, with the boot of my 1991 Mulsanne S loaded with wonderful things, I finally decided enough was enough and drive from IFC2 to my home in Repulse Bay. Due to traffic conditions, I took surface streets rather than the flyovers, and it was on a crowded Queen's Road East in Wanchai, that the "problem" presented itself. The car would stall for a split second, the "Check Engine" light illuminating for that same split second. I made it home allright, but the intermittent stalling continued. At first I thought it was the fuel pump acting up, or perhaps an engine management system relay. Everything checked out fine. I tried the car again. Same problem, and then I noticed an odd odour. I immediately pulled over and opened the bonnet: nothing advserse in that area. But, when I opened the boot I was nearly bowled over by the odour and accompanying "fog" -- I immediately touched the battery shut-pff switch and -- zappo! -- holiday sparks! With a little patience, and the advantage of a complete RR stock toolkit, I was able to adjust the switch and completely secure it in its location on the bulkhead. Problem gone completely. Upon my return home, I checked all connections and thoroughly cleaned everything. I do hope this helps others who have experienced the same thing, and who have been tearing what precious little of their hair that is remaining, out by the roots. Best regards and happy motoring. | ||
| Bill Coburn Moderator Username: bill_coburn Post Number: 587 Registered: 4-2003 |
John THanks for that but what was the problem. Was the switch loose on the body or loose in itself. What do we poor mortals look for? | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 496 Registered: 9-2004 |
Crumbs,That was lucky it did not catch fire,have had simalar probs when the charging system over charges and boils the battery putting the management light on, the smell given of is just horrible. Always happens on a long run. | ||
| John Shostrom Experienced User Username: silvawraith2 Post Number: 31 Registered: 4-2005 |
Bill and Patrick: My apologies for the delay in answering your responses. The battery shut-off switch was loose, where it is mounted the the bulkhead in the boot. Also, the switch itself was a little loose. Yes, the avoidance of Bentley Flambe was a lucky thing ... Thanks to both of you for your comments. Best regards as always, John | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 942 Registered: 4-2003 |
Hi John, Coincidentally, we had to sort out exactly the same annoying problem on the master switch retrofitted to a Silver Dawn just before you started this thread. Although one should ideally be retrofitted to all pre-SZ cars, there are clearly hazards. Incidentally, I have fitted a pair of diodes and a lithium cell to back up the clock and the sound system memory circuits on my car so that they keep time, channels and programming when switched off for holidays and the like. RT. | ||
| John Shostrom Experienced User Username: silvawraith2 Post Number: 32 Registered: 4-2005 |
Hi Richard, I'd be interested in any specifics on how you fitted the diodes and lithium cell on your car. That is a terrific idea and makes loads of sense. Let me know how you're getting on and what the latest is with your cars. Lucky thing we didn't have any fires, eh? JS | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 948 Registered: 4-2003 |
Hi John, Many devices on mid-aged cars have volatile memories which fade after a few days without power when the master switch is turned off. They are the clock, most older CD players, radio presets and trip computers for a start. It's terribly simple to fix this. See the schematic below. The batteries will last at least a dozen years even when called upon regularly. The red boxes are spade connectors. Any 12V Lithium Manganese cell combination will do. I used a pair of 2CR1 6V camera batteries (Panasonic 2CR11108). The battery holder (yellow in the diagram) came from an electrical hobby shop. The diodes are 1N4007, EM513 etc. Solder the two diodes into leads, one with spade connectors at each end, female to the cathode and male to the anode, and the other with the anode to the battery folder as shown. Shrink wrap them to insulate. The two cathodes connect together. Connect an earth lug to the -ve side of the battery holder. Use a multipoint spade adaptor to suit all your volatile-memory devices and the clock. You will need a short new lead to connect to the clock. Turn off the master switch. Find a suitable location near the clock, connect the earth lug to the chassis and secure the battery holder to the console with a cable tie. Unplug the clock and all volatile devices' permanently powered leads. Fit male spade connectors to any lead which don't have one already. Plug the clock supply to the new lead to a diode, and the other devices to the multi plug adaptor. Insert the batteries into the holder. Done.  | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 949 Registered: 4-2003 |
Sorry: I just remembered that I used a pair of Duracell-brand 28L (IEC spec 2CR11108) Lithium-Manganese Oxide 6 volt batteries (not Panasonic), but any quality LiMnO battery arrangement providing 12V will do. | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 951 Registered: 4-2003 |
Hi John, Phew. There's nothing like revisiting something you did way back to make one rethink whether it was optimal or not. On consideration, backup battery life will be greatly increased when the vehicle battery is not new by adding two more diodes at a cost of a few cents. Older but serviceable lead-acid main vehicle batteries settle at about the same voltage level as a new LiMnO cell, and the backup may kick in too early. Two more diodes will drop the changeover voltage by a little over 1V and save the backup unnecessary use. I shall add two diodes to prevent the backup coming in too early on my cars. Hence, a rewrite: Hi John, Many devices on mid-aged cars have volatile memories which fade after a few days without power when the master switch is turned off. They are the clock, most older CD players, the radio presets and the trip computers for a start. It's terribly simple to fix this. See the schematic below. The batteries will last at least a dozen years even when called upon regularly. The red boxes are spade connectors. Any 12V Lithium-Manganese Oxide cell combination will do. I used a pair of 2CR1 6V camera batteries (Duracell 28L to IEC 2CR11108 specification). The battery holder (yellow in the diagram) came from an electrical hobby shop. The diodes are 1N4007, EM513 etc. Solder one to two bits of wire with a spade connector at each end, female to the cathode and male to the anode. Now solder another diode's to the first diode's cathode as shown. Next solder in two more diodes in series to that diode as shown. Connect the anode of the last diode to the +ve side of the battery holder. Shrink wrap the lot to insulate them. Connect a wire terminated by an earth lug to the -ve side of the battery holder. Use a multipoint spade adaptor to suit all your volatile-memory devices and the clock. You will need a short new lead to connect to the clock. Turn off the master switch. Find a suitable location near the clock, connect the earth lug to the chassis and secure the battery holder to the console with a cable tie. Unplug the clock and all volatile devices' permanently powered leads. Fit male spade connectors to any lead which does't have one already. Plug the original clock supply spade connector to the new lead, the one connected to a diode, and the other devices to the multi-plug adaptor. Insert the batteries into the holder. Done.  | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 506 Registered: 9-2004 |
Richard do most of the radio tape cd players have their own back up memory without the coded system. My radio is with the mechanical preselect. For saftey on old cars yes disconnect the battery. My batterys last 4/5 years if disconected. Before connected about three max. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 507 Registered: 9-2004 |
Richard i have now gone into the modern orbit. The brain won't stop unless you can advise and put my thoughts to rest. If the later cars and we are talking the fitment of the OBD2 test 1996 onwards socket for the generic codes will the programes in the managment systems ie emissions engine managment ie ignition timming knock sensor, fuel injection etc be lost over a long period of time if the battery is disconnected and a back up with diodes and lithium run out. Will the systems relearn on its own or will we have to go through a reprograming etc. | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 952 Registered: 4-2003 |
Pat, Modern ECUs and electronics do have lithium cell backup as a compulsory feature as a rule. Those older non-essential ones (DVD, CD, Radio, Trip computer etc) usually have capacitive storage good for a week or so. An engine management system built since 1985, however, will usually retain its diagnostic messages for years without any modification as it will have a lithium cell backup. Imagine if you needed to reprogramme the phone settings in your mobile phone every time you let the battery go flat ? Even a 20,000-series 1987 SZ has lithium cell backups for its memory seats, but usually not for its clock and other systems. With so many watches and clocks that we have these days, it is great to have de-volatised memories, and watches & clocks which automatically reset themselves every 15 minutes by cable, or even by the Frankfurt digital radio clock system since 1976, and to eliminate an hour-long resetting of tens of devices for daylight saving is useful twice yearly. For the devices without backup and not online, I just find it nice that everything is as it was once you turn the master switch back on after a break. Hence the modification I have outlined above. The ECU will certainly retain, or at worst relearn, its data. However, if it goes AWOL due to no backup, and the defaults are written in Chinese text, the heat transfer registered in mega joulskis per zot, the fuel consumption in kilobamps per zikthon, and the fault codes in Swahili, I would be rather annoyed. Hence the backup described above to de-volatise the electronics, especially as it is so simple to achieve. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 509 Registered: 9-2004 |
Just returned thanks for your reply now i will retire and think about all the immobilizer faults that need reprograming with the ECUs when the batterys go flat. | ||
| John Shostrom Experienced User Username: silvawraith2 Post Number: 33 Registered: 4-2005 |
Hi Richard and Patrick My apologies for such a delay in responding -- now it has been laptop problems -- I really appreciate all your help. And the schematics, Richard. Just goes to show how a seemingly small thing can lead to a catastrophe if not thoroughly dealt with. Incidentally, Bentley Hong Kong were unabvle to diagnose the problem and felt the car was running "perfectly" although the stumbling could be due to the gearbox going out ... Cheers to you all. JS |
