| Author | Message | ||
     Graham Burn Experienced User Username: graham Post Number: 36 Registered: 6-2013 |
I've got a really puzzling electrical problem with my 87 Turbo R, when fitting the remote fuse to B5 of F2 to cure the overheating fuse problem I assumed that this fuse was ignition controlled so didn't bother with the battery isolator. As I connected the leads I connected first the powered side and touched the other lead to the surrounding metalwork which resulted in a flash and a popped fuse in the fuse holder. A couple of days later I went out to start the car and when I turned the key to start all the electrics went dead, after a few moments voltage returned, but as the key was turned to the start position they died again and returned after a few seconds. At first I suspected a bad connection somewhere in the supply from the battery which had been weakened by my short but all seems to be in order, I have found that by disconnecting the sensing plug from the alternator everything works as it should and I was able to start the engine, I removed the fan belt from the alternator before starting the engine as I didn't want to cause any damage to the alternator. Suspecting an alternator fault I removed it and took it down to my friendly local auto electrician to test which he did for me but it performed perfectly giving 100A on load. I'm struggling between rain and hailstorms at the moment as my garage is full so doing lots of thinking before checking out various theories but so far I've drawn a blank I'm not thinking earth fault as enough of an earth to drop the supply to about 1 volt would surely show as a smoking wire somewhere? Any suggestions gratefully received. Graham | ||
| Stefan Morley Grand Master Username: myupctoys Post Number: 379 Registered: 7-2009 |
Graham, Assume the field connector on your alternator is fine. Your alternator checked out fine but one of the crimps on my alternator had been partially disconnected. Mine looked fine with the rubber seal seeming intact and the wires exiting the back. But the crimp wasn't making contact with the pin on the alternator. Just pushed it home an all was well. Wouldn't discount a bad earth depending on where it was in relation to possible new found electrical path. Say for example the new bad earth meant that the return path was now through two loads. For example an electrical motor would cause a big initial drop until it was running up to speed, with two things sharing the one current path voltage would proportionally distribute itself across these two loads. Seen some funny issues myself with lights and bad return paths. Add into the mix a couple of crimps being slightly higher resistance!!! It will almost certainly be one of two issues. High resistance in the current path, connector, crimp etc etc or a bad earth. Assuming there is no smoke. Only real way of tackling it is with a wiring diagram and the divide and conquer approach. FWIW the fuel pump in my car draws somewhere between 7 to 11 amps running. Done with an adjustable supply between the ranges of 10 >> 13.8V as one might see starting a car. Pump was only thing on that load. Might help eliminate a few other things. Stefan | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1155 Registered: 6-2006 |
Graham, does the battery cut off switch feel nice and smooth? When you say 'all the electrics went dead' do you mean absolutely everything? There are two large brown wires that run either side of the engine bay, one past the mineral oil res and the other past the engine management ecu. There are two 'giant' Lucar connectors at each. Check to see if you lose voltage there. There is often a 3" fuseable link in the loom by the alternator. Main feed from the alternator Battery terminal to the 'ring main' brown wires. These can burn out. Just looked at your profile Graham - didn't realise you were 'local'.  | ||
| Omar M. Shams Grand Master Username: omar Post Number: 380 Registered: 4-2009 |
Dear Paul, Do you have a photo please? I am interested because my 91 Turbo RL shows 13 Volts on the guage but as she warms up the guage starts to show 11 Volts. Thanks Omar | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1156 Registered: 6-2006 |
Hi Omar, Have you measured the voltage at the gauge? which bit do you want a photo of? The fusable link? I'll see if I have anything. Where the main lead bolts to the alternator you will have the thick main feed from the starter motor. On this terminal you will have another cable that goes to the ring main. On *some* cars this smaller cable starts out as, or for a short distance, a single core fuseable link before being soldered to the usual multi-strand cable. Also check the two 'giant' Lucar terminals. Run engine for a while and then measure the temperature of the terminal housings. If they are warmer than the surrounding cables there must be a bad connection there. Repair the plugs or solder the wires together. Will get back to you soon on other matters. Best regards and many thanks Omar, Paul. | ||
| Graham Burn Experienced User Username: graham Post Number: 37 Registered: 6-2013 |
Hi Paul, my initial checks were at the 2x60A connectors in the front footwells and the 60A connector to the "engine" electrics on the offside of the engine bay which all showed around 12.5 volts until the key was turned when the voltage dropped to around 1.5 which initially made me look for a bad connection which allowed the volts through without load but dropped them when a load was applied. The really puzzling thing is disconnecting the multi plug at the alternator returns everything to normal, I can't think they are causing an earth as the cables are so small a fully charged battery would surely fry them? I have to go up North for a few days, as the Father in law is in hospital, but when I get back I'll get in touch, I'd been puzzling about the fusible link as I couldn't see anything obvious so your description has solved that mystery. All the best for now and thanks for your help so far. Graham | ||
| Ernest Carty Experienced User Username: edcarty Post Number: 40 Registered: 12-2012 |
Hi Omar have you checked the voltage at the Battery with the Engine running?Sometimes the Alternator output drops when it gets warm,this can be due to several things ,An internal fault in the Alternator,also the wiring may get hot altering the resistance and if a high load say the Air Con is on then the Voltage will drop as the Amperage increases.Do you have any Starting Difficulties as this could be a faulty Battery ?Hope this helps and if I can be of further assistance please contact.Regards Ernest | ||
| Ernest Carty Experienced User Username: edcarty Post Number: 41 Registered: 12-2012 |
Graham you said you checked the fusible link visibly?but you will have to check it under load to ascertain its proper state if all is Ok under load then I think like Paul suggests then the the large 60A Lucar terminals could be the problem also where the the wiring loom goes to the multi plug if any LHM has got into this connectin then a High resistance can occur .Hope this helps | ||
| Omar M. Shams Grand Master Username: omar Post Number: 381 Registered: 4-2009 |
Thankyou Paul and Ernest. The voltage at the guage drops when the ac compressor kicks in. Now that its not hot in Dubai, the volatge is fairly good, staying mainly in the white section of the gauge. As things warm up, I am sure we will see the gauge reading at the lowest end of the white. I will follow your advice the next time I tinker with the Turbo RL. Many thanks for your input. Omar | ||
| Graham Burn Experienced User Username: graham Post Number: 38 Registered: 6-2013 |
Hi Ernest, I don't think the fusible link is the problem as with the alternator removed everything works normally and the fusible link is not in circuit with the alternator disconnected. Just got home but it's been peeing down so not had a chance for any further investigation but thanks all the same. ATB Graham | ||
| Graham Burn Experienced User Username: graham Post Number: 39 Registered: 6-2013 |
Slowly making progress now it finally stopped raining for a bit!! Divide and conquer was the way forward, I removed all the permanent live fuses and then fitted them one by one, all OK except the interior lights so looks like somethings gone down to earth on that circuit. Alternator was a right pig to get back on but after lots of levering of the brackets and grinding a bit of a taper on the pivot bolt it finally went together. Had the fuse F1 B3 blow which disabled the starter motor, hope that's not another problem showing up! luckily I had my jumbo fuse assortment in the car so wasn't stranded. Just got to find the problem with the interior lights now!! ATB Graham | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 2986 Registered: 4-2003 |
Omar, The regulator inside the alternator is designed to lower the voltage with increasing temperatures, and the fan on the front of the alternator assures that it is sampling air about 10C above ambient after the radiator has heated the outside air. However, 13V on charge is far too low even at 55C and suggests a bad diode stack inside the alternator. That assumes that you are measuring with an accurate multimeter and that the system harmonics are not messing up the reading. At 55C, about 14.2V would be appropriate, and 15V at 0C. Often a bad diode is the cause, but sometimes a result of shorted turns in the stator. A new stator here costs $10 less than a whole new alternator, and you may upgrade to 140A at that alternator price. You may replace the diode stack, but a new alternator out of a box is best. In Australia you can buy a brand new alternator for the price of a diode stack and bearings. Add a new regulator for good meassure and it makes no sense to do any repair. In short, if I have any suspicion about the alternator I simply replace it by a brand new one. Any savings on a repaired old one would be lost on a single breakdown. RT. | ||
| Omar M. Shams Grand Master Username: omar Post Number: 382 Registered: 4-2009 |
As always Richard - you are bang on the money. your assessment is correct. Now that the weather is good, I have a well behaved Turbo RL. But as soon as the ambients start to creep up above 30 degrees C, I will start to see 11v at idle again. If you have cheap alternators in Australia then they must be GM parts. We will also have those same GM parts here. If you have a part number, I can go to the GM shop and buy one off the shelf. Do you know what that part number is (for the 140amp unit)? Thanks Omar | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 2989 Registered: 4-2003 |
Yes, Omar, it is a GM / Delco CS144. No secret. You may choose any rating between 89A and 250A, but 140A is about right for the standard single 11mm A-section drive belt applied to our cars. You may buy the standard finish (my preference), but chromed or coloured ones are offered for hot-rodders. I have 140A CS144s in my Turbo R and Continental R. When I bought the Conti, the first thing I did was to trash the original alternator and fit a brand new one for good measure. The CS144 fits all SZ Turbo cars and all SZs from the 20k-series onwards. The new ones are vastly superior to the early CS144s, with far better bearings and desirable Schottky diode stacks in place of the more usual straight silicon ones. Schottkys have a very low conducting voltage drop of around 1,5V so do not heat or age like standard 0,7V silicon power diodes. With the improved bearings and Schottky diodes, these alternators last forever. Depending on what is offered, you may need to fit the original drive belt pulley to the new unit as most come with a serpentine pulley nowadays. That is simply a bolt-unbolt effort as the shaft dimensions are always identical. You will probably need to enlarge the power cable eylet from the vehicle's wiring loom with a drill as the terminal’s diameter on 140A alternators is about 1mm larger than on a lower-rated one. The control and indication plug-socket is unchanged. On some, you may need to drill out the thread on the tensioning bolt hole of the alternator as Crewe has a nut and bolt fitting whereas most Delcos have just a bolt with the thread in the alternator. Otherwise, any CS144 fits straight in and has all the correct dimensions. Fitting is a 15 minute job as long as you align the brackets. Fitting is curious the first time, but afterwards you can do it in the dark (as I have done on the roadside at midnight with only the underbonnet light, replacing diodes on a gravel road half way from Sydney to Canberra a few years ago on my Turbo R, but plonked in a new alternator the next day for good measure). Repaired, exchange, overhauled or secondhand starters and alternators are for mugs when new ones with a warranty are so cheap and available. RT. | ||
| Larry Unregistered guest Posted From: 67.80.54.152 |
Is the included internal regulator always the same, with always the correct pre-settings? In replacing it on the 20,000 series cars, is there any considerations in moving the Sanden compressor out of the way without breaking the seal? - Larry (Message approved by david_gore) | ||
| Graham Burn Experienced User Username: graham Post Number: 41 Registered: 6-2013 |
Hi Larry, I got my alternator in and out without disturbing the a/c compressor, with a bit of wiggling it fits through upwards between the radiator and the upper bracket, the fiddly bit was getting the brackets to line up to get the pivot bolt through but I got there in the end. Regards Graham | ||
| Larry Halpert Prolific User Username: larry_halpert Post Number: 134 Registered: 9-2003 |
Thanks Graham! As long as one person relents to answer, the issue ultimately gets solved anyway. Still wondering about the regulator though. Are they all the same in the CS144 and always included? - Larry | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1158 Registered: 6-2006 |
Larry, it is a bugger. But Possible as Graham says. The aluminium pipes can be fragile. I believe the regulators are set to charge to the same voltage. Graham, Could the plug be tensioning the other cables? What happens if you run a cable from the battery positive to the thick ring cables? what happens if you run a cable from battery -ve to body / engine? Are you saying you crank the car, the power goes you release the key for two seconds , and power returns? or hold the key over and the power returns by itself after two seconds ? if the latter does this repeat the cycle while you hold the key in crank. Is the two seconds very equal or a fairly random two ISH seconds? | ||
| Graham Burn Experienced User Username: graham Post Number: 42 Registered: 6-2013 |
Hi Paul, I found I had a very low resistance to earth on the smaller of the 2 wires connected to the main output terminal on the alternator with all the fuses in place. Next I removed all the permanently live fuses and the low resistance cleared, I then replaced them one at a time until it returned which was when I put in the 10A interior light fuse in F1 so at the moment I have no interior lights but at least I can drive the car. The first symptoms I had was when I turned on the ignition all was normal, the warning lights all lit up as they should but when the key was turned to the start position the electrics went dead. when I tested the voltage at various points in the loom I got 12.5v which dropped to a little over 1v when the key was turned to start. The bit I couldn't work out is how does taking out a 10A fuse clear the problem and why didn't the fuse just blow? I'm away now until the end of Feb so will have until then to try and figure it out! Thanks Graham | ||
| Larry Halpert Prolific User Username: larry_halpert Post Number: 135 Registered: 9-2003 |
Thanks, Paul. I appreciate the info on the regulator. | ||
| Ernest Carty Experienced User Username: edcarty Post Number: 42 Registered: 12-2012 |
Hi Graham have you checked that the bulbs in the interior lights are of the correct type,also you do not say if this problem has occourred by itself or was it after say replacing something such as an interior bulb ? Hope this helps | ||
| Graham Burn Experienced User Username: graham Post Number: 43 Registered: 6-2013 |
Hi Ernest, my interior lights were working before my little incident but when I first got the car they were not, this was traced to a trapped wire in the front passenger door causing a dead short. Further to this the relay contacts in the delay unit were burned which prevented the lights connected through that unit from working but after cleaning said contacts all was well. Seems as though I now have another earth somewhere on the circuit so when I get home at the end of the month I'll continue my tracing. Thanks Graham |
