Shaleskin Posted December 29, 2015 Share Posted December 29, 2015 Noticed it more so recently but my voltage fluctuates from 11v - 14v constantly. Pushes up to 12-14v when driving around. When idled the lights pulsate but stops when revs pick up. Would this be the alternator giving up? Battery was purchased beginning of the year by previous owner. Have checked loose connections, cleaned terminals around battery and sprayed electrical cleaner on most. Any suggestions? Quote Link to comment Share on other sites More sharing options...
Shane Posted December 29, 2015 Share Posted December 29, 2015 If you hadn't said you had replaced the battery already I would have said that was most likely. You have a problem that needs sorting before something gives up. Do you have a multi meter? If so measure the charging voltage at around 2500 rpm, I would expect to see 14V constant, with or without the lights on. Get a jump lead and connect it between the -VE terminal of the battery and alternator housing and see if that helps, if so start looking for a earth strap/connection issue. The battery acts as a reservoir and at low revs has to be well charged to prevent the pulsating you describe. Try another battery if you have one available or can borrow one. Do be careful though, I know from experience that these ECUs don't like spikes, I killed an NA ECU from having a loose battery terminal. Quote Link to comment Share on other sites More sharing options...
ManwithSupra Posted December 29, 2015 Share Posted December 29, 2015 I would say its the alternator, Quote Link to comment Share on other sites More sharing options...
Shaleskin Posted December 29, 2015 Author Share Posted December 29, 2015 I'll give that a go Shane. I do indeed have have a multimeter and was reading the voltage from the turbo timer while driving but used multimeter whilst idling. Quote Link to comment Share on other sites More sharing options...
Shane Posted December 29, 2015 Share Posted December 29, 2015 I would say its the alternator, Easy to check. should be putting out 13.8 - 14.4 ish constantly at fast idle regardless of load. If its less than that at the battery, or all over the place on load then before condemning the alternator make a final check measuring directly between the alternator terminal and casing to rule out connection/grounding issues. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted December 29, 2015 Share Posted December 29, 2015 Sounds like the rectifier side of the alternator to me, trouble is I don't think its serviceable like they used to be, so probably a replacement needed. Voltage will depend on the state of the charge in the battery, if its low the voltage goes up and vice versa. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted December 29, 2015 Share Posted December 29, 2015 Worn and / or oil contaminated slip ring and brushes or the inbuilt regulator sound the most likely causes. I am sure some Real Con refurb outfits could fix it, or you could source a good used one. An N/A one should fit, albeit not quite as much Amperage as the TT ones. I doubt you'd notice the difference unless the boot is full of electronic noise making gear. The regulator and the rectifier are separate units within the alternator, and used to be available from Toyota. Changing the slip rings is NOT a DIY proposition though, so if they have tramlines in them I would find another alternator. Quote Link to comment Share on other sites More sharing options...
Shaleskin Posted December 29, 2015 Author Share Posted December 29, 2015 @Chris: That exact scenario happened on my Mr2 (Oil contaminated) I had and found someone to clean up and replace whatever was needed inside. All golden. Checked again from cold earlier today and it was a between 13.6 -14.1 with just engine running and heater fan on lowest speed. Sub + Amp was a removed a few days ago. When full blower, lights + Main beams, rear demister on it went down to 12.9V, sometimes up to 13.1V but that was it. Turned off Rear demister and stayed the same. Turn blower down and went to 13.5V's give or take. Do these sound about right or should it be fairly static around through the 14v mark? Thanks, Ps. I did also put a jumper cable from Alt housing to -VE on battery and this didn't help much, if at all. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted December 30, 2015 Share Posted December 30, 2015 Sounds like the alternator needs rebuilding or replacing, that's not right. Quote Link to comment Share on other sites More sharing options...
Shane Posted December 30, 2015 Share Posted December 30, 2015 @Chris: That exact scenario happened on my Mr2 (Oil contaminated) I had and found someone to clean up and replace whatever was needed inside. All golden. Checked again from cold earlier today and it was a between 13.6 -14.1 with just engine running and heater fan on lowest speed. Sub + Amp was a removed a few days ago. When full blower, lights + Main beams, rear demister on it went down to 12.9V, sometimes up to 13.1V but that was it. Turned off Rear demister and stayed the same. Turn blower down and went to 13.5V's give or take. Do these sound about right or should it be fairly static around through the 14v mark? Thanks, Ps. I did also put a jumper cable from Alt housing to -VE on battery and this didn't help much, if at all. 13.8V is the minimum voltage required to charge the battery, its made up of 6 x cells in series and each cell requires 2.225V before charging takes place. Just out of interest really, you don't have an aftermarket pulley kit or crank pulley fitted do you? Sounds like the alternator needs rebuilding or replacing, that's not right. It does looks like that. Quote Link to comment Share on other sites More sharing options...
Wez Posted December 30, 2015 Share Posted December 30, 2015 The regulator and the rectifier are separate units within the alternator, and used to be available from Toyota. Changing the slip rings is NOT a DIY proposition though, so if they have tramlines in them I would find another alternator. Not on a Toyota but I replaced an alternator regulator a little while back, got a replacement Bosch unit from Allparts, a lot cheaper than a new alternator. Quote Link to comment Share on other sites More sharing options...
Shaleskin Posted December 30, 2015 Author Share Posted December 30, 2015 @Shane - No all standard on Aux system, it has HKS adjustable cam pulleys but that's it on the belt systems. I'll get this one rebuilt if this should be a fairly static number, worth having it fresh again. Thanks for the feedback Quote Link to comment Share on other sites More sharing options...
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