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soorooshg

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About soorooshg

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  • Gender
    Male
  • Location
    London, UK

Garage

  • Garage
    E34 M5 3.6

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  1. soorooshg

    3.6 M5 Alternator Trouble

    Thanks man and yeah I did post on a couple other forums too so I just copy & pasted this on both threads haha, once again many thanks @whiskychaser
  2. soorooshg

    3.6 M5 Alternator Trouble

    Guys just an update, thankfully I’ve finally solved the problem! So I did a few more tests with the help of an auto electrician, and he concluded that there was 2 problems, 1. there is a break in the exciter circuit somewhere between the alternator and firewall, and 2. possibly a fault with either the alternator or regulator (which was only installed a few weeks ago). So we pulled the alternator out again, and for some reason one of the screws holding the regulator had loosened to the point where the back side of it wasn’t making contact with the alternator casing, re-installed it and tightened back up. As for the exciter wire, I cut open the main loom right by the firewall, found the blue cable and stripped a small length of it, and wired in a fresh piece of cable just temporarily to the back of the alternator, creating a new exciter wire. I left the old one there for the time being as I’ll drive it like this for a few weeks just to make sure everything is ok, then go about making it look pretty. Unbelievable how it was such a simple fix but of course with electrics its always the fault finding and investigation which is time consuming. Put everything back together, battery light comes on with ignition, started the car and got a perfect 14.2v on startup, all electrics at full power, very happy. Thank you so much for all the help and advice everyone has given, I really appreciate it
  3. soorooshg

    3.6 M5 Alternator Trouble

    Yeah definitely something very wrong here and it's eating away at me... The regulator is what I originally replaced, its less than 2 weeks old. It's a Bosch OEM part from AutoDoc, I got the part no. from RealOEM, there seems to be a 115a and 140a alternator but both of their regulators have the part number anyway. Also when you say 14.1v regulator, before this new problem, when I was able to excite the alternator I would usually keep the OBC on the volt reading just to keep an eye on it, and it would normally fluctuate between 13.8-14.8 depending on what electrics are running I haven't tried the cluster test, I will give it a go either tomorrow or Wednesday which is my day off. However I forgot to mention that everything did actually work fine, it's as I released the handbrake that all the needles fell down to 0, lights would still remain on (the red brake light also came on when the handbrake was released) I've been told the handbrake has some sort of ground to the cluster that may be causing this? Well the garage I was planning to go to is probably the most well known BMW specialist in the country but yeah I fully understand your point, it would most probably be more worthwhile having an auto elec look at it, trouble is I've struggled to find a good local one specialised in these kinds of cars before. Good shout though, I'll talk to a few local E34 owners I know and see if they have anyone
  4. soorooshg

    3.6 M5 Alternator Trouble

    Right, unfortunately over the weekend things took a turn for the worst, I’m probably going to have to book it in at my BMW specialist unless there’s something very obvious I’m missing. On Saturday, I started it up and as usual was on 9v, after letting the engine warm up I gave it a rev to 4k to excite the alternator but it didn’t do it like usual, it stayed on low voltage for a couple of minutes, then while driving it suddenly spiked to around 16.7!!! Which is obviously way too much, the lights were the brightest I’ve ever seen them. In a 5-6 min journey it was fluctuating between 9-16volts but it still drove as normal. Started it up again this morning to see if it had reset itself (I disconnected and charged the battery overnight) and in addition to the ABS light, the red brake warning light was also on, Speedo and rev counter was stuck on 0, I didn’t get a chance to measure the voltage but I assume it was well below 9 as the engine cut out after about a minute, was running very rough and would barely stay on. I’ve looked at everything I can, and will probably have to take it to Munich Legends which is about 45 min drive away so I’ll have to look at getting it towed as it won’t make it there in this state.
  5. soorooshg

    What have you done on your E34 Today

    Did a full detail consisting of snowfoam, tar/fallout remover, wash, clay bar, polish, glaze & wax, took the best part of 10 hours and I'm very pleased with the results
  6. soorooshg

    3.6 M5 Alternator Trouble

    Someone on another forum pointed out that if you ground pin 12 on the OBD port, it should illuminate the battery light, I tried that and it did turn on the battery light, but unfortunately still bad alternator function. I take it the next thing to check would be the uncoupling diode which I've done some research on. I've attached the diagram for it which I found online, but I'm struggling finding the actual location of it. From what I can tell, it should be somewhere between the OBD port and the fuse box? There's very little information on this which is frustrating, I believe I've found the part number (61311375475) with an image attached, is this what I'm looking for?
  7. soorooshg

    3.6 M5 Alternator Trouble

    Re. Diodes, this may be starting to escalate to depths beyond my admittedly basic knowledge, I'll have to educate myself a bit and get back to that hopefully. Oh I see, I thought pin 7 was specifically for the battery light, I'll double check the diagram but I trust your information. And sorry I didn't explain very well but no, that is one test I forgot to do. By live or negative side I presume you mean on the bulb socket? Sorry if this sounds incredibly stupid but how does one establish which is which? I presume it doesn't matter which way round the bulb is inserted in the socket?
  8. soorooshg

    3.6 M5 Alternator Trouble

    Ah that's a good point I didn't really think of that tbh, I've never tested it that way but yeah it most probably wouldn't hold more than 12v for very long I assume. In regards to the diode you mention, could you be a little more specific please? What exactly am I looking for? Also I did a few more tests yesterday which ended up confusing me even more. 1. Tested pin 4 on the K61 unloader relay, and there is voltage there with the ignition on 2. Pulled the cluster, there is voltage at pin 7 on the yellow 26 pin, for the battery light 3. Connected the battery light directly to pin 7 with a spare piece of wire, turned ignition on and the light illuminated, then I started the engine but still same issue, low voltage until revved up, which is the strangest part of it all since I understand that if the light turns on, the alternator is excited and should be running correctly One thing I forgot to do is to plug the cluster in, take out the battery light & holder, turn ignition on and see if there's voltage on the contacts of where the light is mounted at the back of the cluster. I take it if there is voltage in this situation I should start looking at the cluster? Since there is power going right up to the pin so if theres a broken circuit somewhere it must be inside the cluster? Very confusing situation here, and as I previously said I prefer the pedestrian approach as you say it's not ideal to go running round and replacing every part you suspect might be the issue. End up with a 4 figure bill and still have the original problem. Also no disrespect intended, are you 100% certain that pin no.7 is the one for the battery light?
  9. soorooshg

    3.6 M5 Alternator Trouble

    Yeah the battery issue is a separate one which I think could be partially related to the alternator, and partially because of short journeys and the fact that it’s died probably 50+ times in the past year. Strangely though I had it tested the other day and the guy said it’s all fine and doesn’t need replacing. If I leave it on charge overnight it does reach 12.6v but 2-3 engine starts later (with about 30-60mins driving time) and it’s back down to 10v and no start again
  10. soorooshg

    3.6 M5 Alternator Trouble

    Sorry I’m not following, if you mean to test the battery voltage then it’s currently at 10.6, it does need replacing at some point
  11. soorooshg

    3.6 M5 Alternator Trouble

    Yep just tested that getting 9.6volts at pin 4, although this is with a weak battery so I assume it should be closer to 12 with a charged batt edit: also pulled the cluster and I am getting the same 9.6v at pin 7 with the ignition on. When I turn the key to ‘on’ position (but no engine start as battery is weak) the voltage drops to 8v
  12. soorooshg

    3.6 M5 Alternator Trouble

    Thank you for the specific details, I appreciate it, I'll give that a go tomorrow for sure. If you're referring to testing the battery light, I never actually tested it for voltage but just arrived at that conclusion based on the bulb itself being ok, but not illuminating when the ignition is turned on. When I tried grounding the D+ wire on the back of the alt, I did to to the strut tower nut which is what I always use to jump start the car
  13. soorooshg

    3.6 M5 Alternator Trouble

    I’ve been led to believe that no voltage to the bulb *is* causing the alternator to not charge properly, or am I mistaken? and thank you, I’ll have to pull the cluster again tomorrow and test the resistance. By pin 7 which one are you referring to? There were 4 multi pin connectors at the back of the cluster
  14. soorooshg

    3.6 M5 Alternator Trouble

    Pedestrian approach is preferred in my case as I want to check everything methodically and make sure I don’t miss anything obvious haha as for the battery light, no it doesn’t illuminate at all, whether just with ignition, or the engine on (which it shouldn’t anyway), honestly I’ve never actually paid attention to it so I can’t tell you if it used to turn on before this issue came up, but I assume it must have worked in the past when the alternator was working properly. As I said I took the cluster out and took the bulb out and the bulb itself is fine, hooked it up to a battery and it lights up. I haven’t checked fuse 28 specifically but I have looked at every fuse and they are all in working order
  15. soorooshg

    3.6 M5 Alternator Trouble

    Sorry, mines a 1991. Thank you for the information, by the D+ terminal I assume you mean the smaller cable on the back of the alternator (exciter wire). I had a look at the link and on the diagram it shows 4 relays labelled as unloader relay in the main fuse box, all of which I’ve checked with a 9v battery and they all function correctly. I hate to be spoon fed but I’m quite a novice when it comes to electrics, what would you suggest I do next?
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