MZpog 10 Posted January 14, 2015 Last night my daily drive ran out of electricity and I needed recovering (sort of). Car started but soon after the ABS light came on, radio switched off and the dash dimmed. As the ABS light has done this recently before and was fixed by turning the ignition off/on I did this and the Raddo wouldn't start. It would light up as norm but not enough power to turn the engine. Anyway after a 10 minute rest I tried it again and vroom, it lives. Drove the car for about 5 miles with no battery warning light, but occasionally making a screaming noise from the belt or alternator. Again ABS light lit, dash dimmed and car started running like a pig (down on cylinders). Pulled over and car was dead as a dodo (would light up but no turning). Recovery guy came out, hooked up a battery booster (vroom) and left this under the bonnet while I drove home (fine apart from the snow). Battery left on charge until tonight when I have a look at it. Now I know my fault is with the battery or alternator but which would you guess? If its the alternator is there any upgrade I should consider and where would stock one for next day delivery? Quote Share this post Link to post Share on other sites
sankysvr6 0 Posted January 14, 2015 Only way to tell for sure if its the alternator or the battery is to have it tested, or test it yourself with a multimeter if you have one. Not sure about an upgrade for the alternator, but if you do upgrade to a higher current rated alternator. I think you might have to upgrade the battery as well. I would just stick with good quality stock items. Try places like ECP, GSF, AVS, VWheriatge or carparts4less for next day delivery. Quote Share this post Link to post Share on other sites
Jim Bowen 1 Posted January 14, 2015 Yeah, its quite easy to test with a cheap multimeter. Or get to a place that sells battery and if they are decent they will check it all out for you. You just hook up the multimeter to the battery terminals and check the voltage, should be over 12v with engine off, and then it should rise up to over 14v with engine running and alternator charging it up. Did the recovery guy test or check much? Quote Share this post Link to post Share on other sites
g0ldf1ng3r 13 Posted January 14, 2015 what recovery are you with? did they not do a check before getting you started? :( I know RAC did a battery test & an alternator test when my parents BMW let me down last year. the guy then did the same as you explain, put the booster on & left it in place whilst I drove to their mechanics Quote Share this post Link to post Share on other sites
MZpog 10 Posted January 14, 2015 what recovery are you with? did they not do a check before getting you started? With Greenflag and only have basic cover so no testing done. I'll be out with the multimeter tonight to check voltage. I'm hoping its the battery, that being the cheapest. Quote Share this post Link to post Share on other sites
fla 9 Posted January 14, 2015 Check the blue exciter wire. This runs across the front of the block from the alternator and governs charging. If its broken the alternator won't generate any current so your battery won't charge. Quote Share this post Link to post Share on other sites
MZpog 10 Posted January 14, 2015 Check the blue exciter wire. This runs across the front of the block from the alternator and governs charging. If its broken the alternator won't generate any current so your battery won't charge. Are we talking 2.0 16v here or VR6 or both? Mine's a valver. Quote Share this post Link to post Share on other sites
fla 9 Posted January 14, 2015 Its fitted to both but you're right the route is for the vr is as I've mentioned. Look out for a thin blue wire from your alternator. Quote Share this post Link to post Share on other sites
MZpog 10 Posted January 15, 2015 Well seems my alternator is working as the multimeter showed over 14v when running. Fitting a replacement (larger) battery tonight assuming this is the problem. If its not the battery then its must be down to a loose belt or intermittent alternator fault (lets hope not). Quote Share this post Link to post Share on other sites
Dox 22 Posted January 15, 2015 You want 12.6V accross the battery after the car has rested for a few hours. 14V ish with the engine running and under load - (lights HRW heater radio on etc) The exciter wire is also the dash charging light wire - does it light up when the ignition is on without the engine running? An engine once started will run with the battery disconnected if the alternator is working correctly. If the alternators brushes are worn they will skate on the slip rings arching and sparking, if you remove the brush pack and there's soot on the shortest of the brushes they're worn out and need re[lacing. Check all the battery, engine earth and starter connections for cleanliness and security as well as the main alternator cable to battery connections. If the engine once running cuts out and refuses to restart its either the alternator or wiring connections IMO Quote Share this post Link to post Share on other sites
MZpog 10 Posted January 15, 2015 You want 12.6V accross the battery after the car has rested for a few hours. 14V ish with the engine running and under load - (lights HRW heater radio on etc) The exciter wire is also the dash charging light wire - does it light up when the ignition is on without the engine running? An engine once started will run with the battery disconnected if the alternator is working correctly. Was showing 14v+ when running and lights on so assume alternator working. Didn't check the exciter wire as above voltage seemed fine. Didn't try to run without the battery connected either. Hope it is the battery as it didn't want to run the other night with it connected and lights on. Quote Share this post Link to post Share on other sites
Dox 22 Posted January 15, 2015 Was showing 14v+ when running and lights on so assume alternator working. Didn't check the exciter wire as above voltage seemed fine. Didn't try to run without the battery connected either. Hope it is the battery as it didn't want to run the other night with it connected and lights on. Its not good practice to disconnect the battery with the engine running TBH, the point I was making is the alternator will power the engine with a completely dead battery. A good alternator has the capacity to run the engine, all electric ancils and still have enough power to charge a depleted battery. Quote Share this post Link to post Share on other sites
MZpog 10 Posted January 15, 2015 Its not good practice to disconnect the battery with the engine running TBH, the point I was making is the alternator will power the engine with a completely dead battery. A good alternator has the capacity to run the engine, all electric ancils and still have enough power to charge a depleted battery. That's worrying me now because I had a depleted battery and the car ran like a pig, possibly not enough alternator power to keep charge, run lights and ignition. I suppose a slack belt would cause my problem. Quote Share this post Link to post Share on other sites
MZpog 10 Posted January 15, 2015 Well I swapped my battery for a good one tonight and checked the running voltage which showed 14.3 so I switched the lights on and down to 14.1 so I go the whole hog, lights, heater, rear screen, fogs and it drops to 11.5 so it looks like the alternator is in fact dead. Replacement to be ordered tonight, bugger. Quote Share this post Link to post Share on other sites
Dox 22 Posted January 15, 2015 Well I swapped my battery for a good one tonight and checked the running voltage which showed 14.3 so I switched the lights on and down to 14.1 so I go the whole hog, lights, heater, rear screen, fogs and it drops to 11.5 so it looks like the alternator is in fact dead. Replacement to be ordered tonight, bugger. Check the wiring first? Regulator / brush pack is usually around £30. 2 screws removes it and check the shortest carbon brush for sooty deposits on the end Quote Share this post Link to post Share on other sites
Dox 22 Posted January 15, 2015 http://www.ebay.co.uk/itm/ALTERNATOR-REGULATOR-VW-PASSAT-Estate-3A5-35I-2-0-16V-136BHP-Top-German-Quali-/321430516866?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item4ad6c07482 Thats just an example, you need the correct one for your alternator Quote Share this post Link to post Share on other sites
MZpog 10 Posted January 15, 2015 Check the wiring first? Regulator / brush pack is usually around £30. 2 screws removes it and check the shortest carbon brush for sooty deposits on the end I'm off to check them now, could it be just these that have failed? Quote Share this post Link to post Share on other sites
MZpog 10 Posted January 15, 2015 Removed the brushes and they look pretty worn, one more that the other....... [ATTACH=CONFIG]80493[/ATTACH][ATTACH=CONFIG]80494[/ATTACH][ATTACH=CONFIG]80495[/ATTACH] Quote Share this post Link to post Share on other sites
Dox 22 Posted January 15, 2015 Removed the brushes and they look pretty worn, one more that the other....... [ATTACH=CONFIG]80493[/ATTACH][ATTACH=CONFIG]80494[/ATTACH][ATTACH=CONFIG]80495[/ATTACH] They look very worn, compare them to the ebay listing above. If the bearings are good, the slip rings not too worn (these are the copper rings the brushes come in contact with) you may get away with a brush pack Quote Share this post Link to post Share on other sites
MZpog 10 Posted January 16, 2015 They look very worn, compare them to the ebay listing above. If the bearings are good, the slip rings not too worn (these are the copper rings the brushes come in contact with) you may get away with a brush pack Here's hoping to get away with brush pack (ordered). Quote Share this post Link to post Share on other sites
MZpog 10 Posted January 19, 2015 Well the new brushes were fitted and showed 14.6 at first, but this reduced once all electrics switched on so it looks like the alternator is at fault. Quote Share this post Link to post Share on other sites
Hairyarse 10 Posted January 19, 2015 That's a shame, but at least you know ;) Quote Share this post Link to post Share on other sites
sparks 0 Posted January 19, 2015 Well the new brushes were fitted and showed 14.6 at first, but this reduced once all electrics switched on so it looks like the alternator is at fault. wuuh wuuh wuuh wuuh lets back it up abit here speaking from a electrical engineers point of view a alternator on tick over yes should put 14.6 volts out well anything above 1.5v of 12v or what every battery your are charging so you alternator is reading right on 14.6 v running all the electrics on tick over is not what its designed for i would say at least a rpm speed of 2500rpm then check the alternator at least give it a fighting chance modern engines actually increase base line rpm (800-900) to cope with this but corrados dont before you waste good money on a new alternator do the above check !!!! sounds to me like you have a duff battery and a slipping alternator belt which killed your battery fixing both will cure your problem cheers stu ... Quote Share this post Link to post Share on other sites
sparks 0 Posted January 19, 2015 Didn't try to run without the battery connected either. Hope it is the battery as it didn't want to run the other night with it connected and lights on. also never run a car without the battery what comes out the alternator is not smooth DC it relies on the battery to smooth it like a capacitor disconnecting the battery allow all the spikes to go into your electrics which is not good for ecu's!!!!! Quote Share this post Link to post Share on other sites
MZpog 10 Posted January 20, 2015 wuuh wuuh wuuh wuuh lets back it up abit here speaking from a electrical engineers point of view a alternator on tick over yes should put 14.6 volts out well anything above 1.5v of 12v or what every battery your are charging so you alternator is reading right on 14.6 v running all the electrics on tick over is not what its designed for i would say at least a rpm speed of 2500rpm then check the alternator at least give it a fighting chance modern engines actually increase base line rpm (800-900) to cope with this but corrados dont before you waste good money on a new alternator do the above check !!!! sounds to me like you have a duff battery and a slipping alternator belt which killed your battery fixing both will cure your problem cheers stu ... Battery was changed for a known good one before the test (this was showing 12.6 after a rest). Tried adding some RPM but no change in voltage when I'd have expected it to raise a bit. Also no belt squeal during the test. Have bitten the bullet and bought a new alternator and hopefully this'll cure the problem. Quote Share this post Link to post Share on other sites
