Amart88 Posted May 31, 2012 Report Share Posted May 31, 2012 (edited) Ok, I had stated this in an earlier post but I found this so interesting that I wanted to make one about this. You all probably know that alot of GM vehicles from 2006 and up have PCM controlled voltage which is a pain in the ass. Some in particular have the 2-pin alt plug with the inductive ground pickup around the negitive battery terminal so the PCM can control the voltage. My car is one of these. Ever since my latest install, my voltage is around 12.9 and goes to 13.8 with lights on. if i start bumping the voltage will go down to 13.3 ish and then jump to 14.2 then down to 13.7 and so on. I thought it used to be higher before this build. Is there any way to "trick" or manipulate that ground sensor ring so that it will let the PCM charge the system better? I have it around a Knu 1/0 ground now because the stock ground is gone as it was not needed. Is there a certain "sweet spot" to have this attached? It would be cool if there were some way to do this without spending a 1000 dollar son something that may or may not work. Also i think any info on this could help alot of folks out there as the dealer will not tell you anything. It's tiring when you put all of this work into a system and then find out the PCM is being stupid and people tell you to buy another 600 dollar alt to fix it. I am getting an MLA pcm module but i'm not sure if that will stop the voltage from bouncing around so much. What did you guys with these PCM's do to get the most out of it? any tricks or stories? Thanks I no i'm not alone. Thanks Pic of said ring: http://www.yourcobal...ng-100_1936.jpg Edited May 31, 2012 by Amart88 Quote My 2005 s10 blazer build. 4 zcon 18's walled. Link to comment Share on other sites More sharing options...
8ight Posted May 31, 2012 Report Share Posted May 31, 2012 14v battery. Quote I'm gonna hate Link to comment Share on other sites More sharing options...
Amart88 Posted May 31, 2012 Author Report Share Posted May 31, 2012 14v battery. ?? Actual car battery? I can;t fit anymor ein my trunk. Already have 3 xs 12 volts Quote My 2005 s10 blazer build. 4 zcon 18's walled. Link to comment Share on other sites More sharing options...
SnowDrifter Posted May 31, 2012 Report Share Posted May 31, 2012 14v battery. How would that help him? A 14v battery needs to be charged above 16v. Hell, the resting voltage on one of those is higher than his charging voltage right now. I don't think that would fix Amart's problem... Quote ~~~~~~~~SAY NO TO PHOTOBUCKET~~~~~~~~ Snow's DD-1 tracks here: https://www.stevemeadedesigns.com/board/topic/167433-snows-dd-1-tracks/ My take on OFC vs CCA: https://www.stevemeadedesigns.com/board/topic/110381-things-that-piss-you-off-in-the-car-audio-world/?do=findComment&comment=2461444 Link to comment Share on other sites More sharing options...
8ight Posted May 31, 2012 Report Share Posted May 31, 2012 14v battery. How would that help him? A 14v battery needs to be charged above 16v. Hell, the resting voltage on one of those is higher than his charging voltage right now. I don't think that would fix Amart's problem... That was in response to tricking his computer. It's not the right solution at all, don't know why I didn't mention that. Don't I suck? :L Quote I'm gonna hate Link to comment Share on other sites More sharing options...
Amart88 Posted May 31, 2012 Author Report Share Posted May 31, 2012 14v battery. How would that help him? A 14v battery needs to be charged above 16v. Hell, the resting voltage on one of those is higher than his charging voltage right now. I don't think that would fix Amart's problem... Correct, I would not be able to even charge a 14v. I'm just more curious about what others did with their PCM controlled voltages. I like to keep my options open and hope to find a fix that won't cost an arm and a leg. I like my car and my system I just need to sort this out. Everytime I bring this up its like a giant brainf*ck lol theres not too many places out there that know anything or are willing to even touch this stuff. It's kind of sad. I'll try the MLA i guess. Also, not to knock external vcm's but I have heard that they can overheat your alt(s) and cause alot of problems with batteries and what not, Besides xs dosent even make them anmore Quote My 2005 s10 blazer build. 4 zcon 18's walled. Link to comment Share on other sites More sharing options...
UnderLoK Posted May 31, 2012 Report Share Posted May 31, 2012 (edited) You want your amp's ground to go through that pickup if you were to "do it right". Outside of that there isn't anything else you can do unless your vehicle is one with an override. Most of the SUVs and trucks (not mine) will leave economy mode and go into charging mode if you manually turn on the lights or on models with a tow button if you hit the tow button. Those are the only two tricks I know of. With these vehicles you really only have a few options. Get AD based alts (which is what the HO alt companies should be suggesting) and deal with the charge warning, go with externally regulated and deal with a charge warning, or get an MLA. For the record I bought an MLA last year, just never got around to putting it in, should have it in next weekend though finally. If I were you and if you don't already have an HO, get an AD based alt instead and just deal with the charge warning on the dash (tell the alt manufacturer what you're doing and they will give you instructions on how to wire it up). In reference to your voltage... It's walking right? By that I mean one minute (it shouldn't be constantly moving every second) it's sitting at 13.2, the next it's at 14.1, then 13.6. then 12.8, and so on? If it's going from 14.2 to 13.3 when you turn it up then it's drop, not the PCM... The alt should still provide amps no matter what the voltage is. I have next to zero drop even when in economy mode (12.8-13.2). Edited May 31, 2012 by UnderLoK Quote If at first you do not succeed, you are doing it wrong! -ARSCheck out my walled TBSS build over here4 Fi Team 18s on 2 Cactus K9 DS18 doors on 2 MBQ 1Ks, Vifa pillars on a STL4.500 Pioneer X8500 6 XS Power D7500, 1 3400S Second Skin 2 270a Mechman Alts Link to comment Share on other sites More sharing options...
Amart88 Posted May 31, 2012 Author Report Share Posted May 31, 2012 (edited) You want your amp's ground to go through that pickup if you were to "do it right". Outside of that there isn't anything else you can do unless your vehicle is one with an override. Most of the SUVs and trucks (not mine) will leave economy mode and go into charging mode if you manually turn on the lights or on models with a tow button if you hit the tow button. Those are the only two tricks I know of. With these vehicles you really only have a few options. Get AD based alts (which is what the HO alt companies should be suggesting) and deal with the charge warning, go with externally regulated and deal with a charge warning, or get an MLA. In reference to your voltage... It's walking right? By that I mean one minute (it shouldn't be constantly moving every second) it's sitting at 13.2, the next it's at 14.1, then 13.6. then 12.8, and so on? If it's going from 14.2 to 13.3 when you turn it up then it's drop, not the PCM... The alt should still provide amps no matter what the voltage is. I have next to zero drop even when in economy mode (12.8-13.2). Thanks for the reply, i read through you r build log last night Nice job by the way . Umm I will try to put it on the amps ground and see if that helps. Also The voltage will stay at 13.8 with the "auto lights on" and when I start bumping it will go down a small bit but sometimes when i bump it wil spike to like 14.1 or 2 then back down to 13.8 then back to 14 ish etc. Sometimes it will just drop to 13.4 and slowly climb back up but sometimes it will spike to 14.2 for some reason and sometimes it wont. I do have a PCM mla on they way soon. also, whats an AD alt? Edited May 31, 2012 by Amart88 Quote My 2005 s10 blazer build. 4 zcon 18's walled. Link to comment Share on other sites More sharing options...
Amart88 Posted May 31, 2012 Author Report Share Posted May 31, 2012 (edited) Well, I tried the ground ring over the amps ground and my voltage went nuts. Bouncing all over the place, 13.4 14.5 13.2 14.1 13.7 etc... so I put it back. ugh. These PCM jobs are head scratchers for sure. lol Edited May 31, 2012 by Amart88 Quote My 2005 s10 blazer build. 4 zcon 18's walled. Link to comment Share on other sites More sharing options...
UnderLoK Posted June 1, 2012 Report Share Posted June 1, 2012 I missed the part where you mentioned you removed the factory ground? Mine has all sorts of crap running to that ground so that might have something to do with it as well. Basically you want everything that grounds to go through that pickup (amp ground and factory ground). If I remember correctly it constantly samples load and adjusts accordingly, but it should only be looking every 30-60 seconds not every second. That makes me think it might have something to do with that factory ground. This is all info I read about the charging system and second hand knowledge from some alt manufacturers and techs I've talked to over the past couple years, I have too many grounds so I was never able to try it myself. Quote If at first you do not succeed, you are doing it wrong! -ARSCheck out my walled TBSS build over here4 Fi Team 18s on 2 Cactus K9 DS18 doors on 2 MBQ 1Ks, Vifa pillars on a STL4.500 Pioneer X8500 6 XS Power D7500, 1 3400S Second Skin 2 270a Mechman Alts Link to comment Share on other sites More sharing options...
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