shock & horror, a mixer in a single malt..... best hope TSC doesn't hear nice sunny day today and im stuck at work, much rather be trying to get to the bottom of this problem rather than having to do it in the dark later. Grrrrrrr
right - progress fitted everything and the light on the dash is going off, and the batt is charging so thats good news, the voltage seemed to be a bit lower, (13.6 - 14.01 with everything on full) and a more consistant 14v with everything off. i ran the car for about 5 mins and at first the lights were solid, ie no surging but towards the end of the 5 mins they started their old tricks again. they are surging a little and now on idle you can see the alt light fickketing very feigntly, i'm not too fussed abot that tho. so all in all i dont realy know what to make of it, do you think theres a chance its the reg or possibly the alt?
Some success, at least Sounds like progress in the right direction, that voltage behaviour sounds exactly like mine: 14V off-load, dipping down into high- then mid-thirteens as loads are added. I hope this is normal (I'm measuring these voltages at the cigar lighter socket). I'd say mine might be a tenth or two higher than pre-connection-scrape, perhaps explaining the now well-behaved 'charging status' LED or whatever it's proper name is. May be time to check some earths around the place (as recommended by TSC in another thread very recently), I think your alternator is doing better now. My GSF brush/reg. pack had 14.0V printed on it, and it does just that, as yours seems to be doing now. May have to undo a few earths, clean and replace. Hoping that some others will chime in here with more detailed suggestions. Pete
yeah, could prob do with cleaning all the earths up, that however is a weekend job with some daylight. how do you measure voltage from the cigarette lighter?
Light one of my special roll-ups... ... and just feel the volts man Seriously though, I've got a home-made digital voltmeter plumbed into a cigar-lighter plug. Agreed about the earthing, daylight job. I'm planning a trip up my driver's footwell this weekend to investigate whether I can improve my brake servo performance by tactical application of a Dyson. Edit: see my post on the Chassis Forum a few days ago for the reasoning on this; really, do.
Wild geese chased, wrong trees barked up? Morning Farquare! Just had a big change of mind on what's going on in your engine bay (and recently in mine). The whole 'flickering headlights' thing... That indicates some dramatic fluctuations in voltage at the bulbs, but if yours are like mine were; at a (fairly steady) frequency of only a few Hertz. I don't really know how this flicker frequency changes with engine revs, only looked at it with engine idling, or close to it up behind someone in a traffic queue. I'd like you (or anyone with similar symptoms) to look for one or two things next time you 'fire her up'. Is it OK at first, but flickering headlights come back as time goes by? (Know yours does this Farquare) Does the voltage ouptut of the alternator go up (out of spec) as the lights start flickering? Are any of your engine mounts in poor condition? Is your alternator belt not all that new (even though correctly tensioned)? Do you have to top up the coolant more than you'd expect? By this point Dear Reader, you're certainly worrying about my intake of the aforementioned single malts, and special roll-ups, but bear with me... If the voltage regulator and brushes are pretty new, the only reason that this assy is failing to do its job right must be a dodgy connection. We've worked on the ground to the alternator body, and assume that the live feed wire is intact; that just leaves the brush/slip-ring contacts. After the 'skating on WD40' incident was over we were back to nearly square-one, if not exactly there. So time to check early assumptions. "Bearing probs would only make it audibly noisier" Wrong Pete. Bearing/shaft wear will cause the slip-rings to describe a non-concentric path; and, with the right (wrong!) vibrational input and fan-belt/brush spring resonant frequencies...BounceTastic. Loose engine mounts would make this vibrational input more likely. I've got a very loose rear-mount, and probably have had for some time. Worn-out old fan-belt would presumably not help, neither. New brushes may conceal this situation for a while as you've got stiff new, well compressed springs shoving your nice long brushes up against the slip-rings (baby). As for the coolant, I'm well out on a limb here, but... I think a working, correctly pressurised, correctly constituted and topped-up coolant system may act as a vibration damper for your engine. Especially when it's warmed up and at full pressure. Think of the instantaneous torque at your crankshaft as your individual cylinders get their 'bang'- rather 'spikey' would you think? Then remember that your alternator belt connects this straight up to your water pump and alternator. (Admittedly via a material that must have some give in it). I had a coolant leak, that coincided with a noisy alternator (didn't notice any voltage probs or flickering lights then, but wasn't looking!). fixed the coolant leak, and the noise went away mysteriously too. Try shaking a bottle of still water in one hand, and a bottle of fizzy in the other (I had to try it to convince myself). The still water keeps going crash,crash,crash. The fizzy one turns into more of a uniform, pressurised emulsion, no crashing. This could be (another reason) why a cold engine sounds so much worse than an up-to-temp. one. And why my noisy alternator got fixed when I fixed the coolant leak (temporarily). Don't think it's relevant to your situation Farquare, 'cos yours gets worse as the engine warms up, therefore probably more to do with the fanbelt getting floppier (with friction heating) and more likely to 'flail'. Due to the frequency of the flicker, I'm fairly sure that it's this 'flail' that's causing the vibration that's causing the brush bounce ('cos your bearings are on their last legs). Phew. Any takers? Pete
wow...... what a post, and although i probably only caught the gist of it and understand only about 1/2 of what your trying to say in summary you want me to fill my cooling system with a fizzy water and alcohol mix!! seriously though, now you mention the bearings the pully seens a little worn By that i mean i picked up the alternator by the pully and i could feel the pully moving (like an end float) i guess that would make the slip rings sit not square on the brushes especially on my incredibly lumpy idle (thanks new cam). I guess this also accounts for the flicker becoming less pronounced above idle - but not going away completely. Engine mounts are okay, well as good as you get on an 8v digi and the cooling system seems to be okay too. SO looks like its the alt thats at fault, now i have a spare but as i recall it puts nothing out at all, so i'll clean it all up and see if i can get that to give a voltage with the good reg. If not looks like i have to get a new alt, unless there is a way to swap the bearings over (the pulley has no movement in the fecked alt) the only thing i cant get my head around is why the volts go up when the engine gets warmer, surely if the reg is off the slip ring (even momentarily) then the volts would drop, unless it overcompensates its self? Thanks for the replies pete, you know your electrics. i feel it may be new alt time.
You're getting it "then the volts would drop, unless it overcompensates its self?" I think that's exactly what it'll attempt, trying to keep some sort of 'average' voltage about right, by overcooking it when it is in contact. Sounds to me like you'll be OK making one good alternator out of the two you've got. Haynes Electrical and Electronic Manual is pretty good for diagnosing what's good and what's not. There's a great "how to" on here somewhere about replacing bearings (but for a 90A Bosch alt. I think, bet the internals are similar). Don't forget to check shaft bearing surfaces for wear before going down this route though. Pete Edit: Got it all a lot clearer in my head now too (I hope!) Usual apologies to anyone who's done this work before, or for whom it's a grandmother/egg/suction/tutorial thing. Edit2: And as a friend's just pointed out, if your bearing play is (only) in the axial direction, you could still have trouble if your slip-rings have grooved. The brushes then may be trying to jump up and down 'cliff-faces'. This is at least as likely I think, given your 'end-float' observation (if you also have such grooving).
no apologies needed, i searched heaps but couldn't find any similar situations on surging lights. looks like thats what i'll be doing tonight then - stripping down the spare alt. Next time im in abingdon i'l get you a malt/exotic cigarette/beer good info, i'l let you know how i get on.
best laid plans of mice and men.... and all that. ended up doing a bit of "business entertaining" tonight, hopefully get away sharpish tomorow in order to catch gsf for a new alt on sat morn if things go pear shaped.
right pete, looks like i have 2 fooked alternators. cleaned the other one up and put it on but its not givingany out-put. interestingly there is no free play in the pully in the duff alt, but i cant be bothered splitting them. Interestingly i was out for a drive earlier and the flickering lights seem to be more prominent when hitting a bump, i guess that kinda ties in with your 'non concentric slip ring theory'. off to gsf in the morning for a replacement alt, i dont supose you could trade in the normal alt for a 90a one? or would you have to have aduff 90a one to exchange?
What a shame Very sorry to hear that you haven't come out with a gud'un, after all your efforts. [:^(] It will hardly be any consolation to you, but mine is working noticeably better since the contact-scraping business. I'm seeing much healthier voltages, especially in the early stages of my journeys while the alt. is working hard to replace charge used by the starter motor. I don't think companies doing exchange alts are too bothered exactly which units they take off you, but I haven't any personal experience, just heard it from one or two folk. A question that remains unanswered, which would be good to know in context of the opinions expressed about the merits of GSF versus VAG regulators, is "Do the VAG regulator/brush units come with new screws?" The best possible contact would be if you cleaned up the surface that the brush-pack bolts up against (and vaselined for moisture-proofing), but if the VAG ones do come with shiny new screws, that would be nearly as good. Anyone?
after i had a few bad regs from gsf i got mine from LCUK was about 18 but the bat light goes off very early in teh revs unlike teh gsf one and it gives a perfect 14.5v. I dont think my alt it to healthy so its doing well to put out the right voltage.
Sorry, me again Hi Folks, Sorry to cause this thread to 'bump' into your faces again, but I've got a new observation that some of you will probably be able to help me explain (and prevent lots of hair-loss as I rummage through the wiring diagrams). Since cleaning-up/improving the ground connection of my volt reg. I've noticed that for the first few mins of running after a cold start I see voltages of up to 14.7 as measured at the cigar lighter socket. This quite quickly goes down towards the 14V, steady-state (low-load) voltage I expect to see. ('Cos the volt reg. says 14.0V on it!) I imagine that this reflects the fact that straight after a cold start, the battery voltage will be rather lower than normal 'cos of the charge used by the starter motor. The alternator will then try to sort this out by putting out a big current, charging the battery fast, and because of the volt-drop down the 'charging cable' this could cause the alternator end of this wire to be at more than 14V. But this would only explain my 14.7s if the cigar lighter is seeing the voltage at the alternator end of this wire, which surprises me. Edit: or it could be to do with volt drops in ground connections? Fairly sure that the change of behaviour is in a good direction 'cos the dash light's no longer doing it's annoying flicker at idle... Any thoughts? (I'll obviously try to sort this out myself, but someone may be able to point me in the right direction) Pete Edit 08/03/07: Have read some more on this topic, and found that the output of the voltage regulator is carefully controlled with respect to temperature. The colder the battery/alternator the more volts can be tolerated (by the battery). The voltage regulator has a compensation mechanism built into it's 'chip' that allows it to put out more volts when cold, stabilising to the nominal (14.0V in my case) when it warms up to normal operating temperature.
just a little update, i got a new alternator and battery from uni part (gsf didnt have any in stock) prob payed a bit over the odds (20 or so) but the difference is night and day. the car starts a hundred times better, used to have to coax it in to life but now even when standing overnight i just need to turn the key and it likerally jumps in to life, it feels pretty agressive and i like the feeling of not having to worry about getting the car to start. surging is gone too at least on the dash, the headlights still look flickery but i think thats a vibration problem due to a combination of the above posts. cheers for all the help guys.
