06gta 1 Report post Posted February 4, 2013 (edited) 156 JTS Very hot day last Wednesday - a/c full boar and using windows the a/c nearly stalls. Also alternator has a whine (heard through radio speakers) in it that has become worse after recent amp installation. Amp turns on @ MAR Static Battery voltage 12.6 Kick over but in doing so drops to 9.6 then raises to 13.5 Slowly drops down to 12.5-12.8 range Removed and fully charged battery Static Battery voltage 12.6 Kick over drops to 11 then raises to 13.8 Slowly drops down to 13.5 Turn on lights, a/c, etc and drops to range 12.6-13 Turn off accessories except side lights - raises to 13.5 Remove -ve terminal - car doesn't stall and stays @ 13.5 (unloaded - no a/c etc) Turn on everything and drops to 13-13.2 Have now put my 147 GTA battery into the JTS and still reads similar Had JTS battery tested and has 400cca (rated at 500cca) So I'm not sure if the battery is cactus or the alternator Any help appreciated Edited February 4, 2013 by 06gta Quote Share this post Link to post Share on other sites
Smaky 73 Report post Posted February 4, 2013 I would first off check the engine earth, it's attached the gearbox mounting bracket behind the air filter, loosen the nut off and retorque it to break any corrosion there, if you have contact spray then that will help too, then check the volatage again, Ideally with all accesories off it should be 14 - 14.4V but anything over 13.4V is charging the battery, as 1.4V is required by the electronics at about 3Ah to run the engine. If that fails to improve things then don't rule out the starting motor, this has a solenoid which can short and cause a drain on the charging circuit, normally a quick clean up is all that needs to be resolved. If the battery was faulty I'd expect it to read 10.8V max when fully charged, showing that at least one cell was dead, replace battery. Alternator, well you can get a whine from a failing alterator, whether the regulator pak is going or the bearings are dieing, but 9/10 it's a bad earth as before, but the low output of 13.5V is not rare, but cerainlynot the norm, if you want to then you could try another alternator, but batteries and starters are easier to do first. Quote Share this post Link to post Share on other sites
K9d 108 Report post Posted February 4, 2013 When I start my 156 the fuel gauge reads about 1/8 lower than it really is for about 5 minutes then slowly recovers to normal, is this a sign of a battery on its way out ? Quote Share this post Link to post Share on other sites
06gta 1 Report post Posted February 5, 2013 Thanks Smaky - will check the earth from engine to chassis, re test and advise. How do I check and clean the starter motor solenoid? Quote Share this post Link to post Share on other sites
06gta 1 Report post Posted February 5, 2013 Lights and accessories were used in the car today 12.8v static 13.6 Idle 12.7-13 under load Removed the earth bolt and cleaned using contact cleaner (it looked pretty clean) Retested but no change to figures Quote Share this post Link to post Share on other sites
Smaky 73 Report post Posted February 5, 2013 Rhat all sounds acceptable, fuel gauges can do that sometimes, after all they are only a guide. Quote Share this post Link to post Share on other sites
06gta 1 Report post Posted February 6, 2013 (edited) Asked the wife if the JTS had the whine on way to work as I've now re-instated the amps fuse - she tells me that no noise but the radio is asking for a code. I'm pretty sure the books have a radio code in them - what's involved in getting the radio re-coded? EDIT - sorted, just had to enter code in - too easy! Thanks Edited February 6, 2013 by 06gta Quote Share this post Link to post Share on other sites
