tristanlee85 Posted July 23, 2007 Report Share Posted July 23, 2007 This just started happening the other day. I can see the lights dim a good bit and the speakers will pop. It'll do it at idle (when I notice it the most), decel, and accel as well. I've already replaced the alternator recently with one that tested dead and the one that is in there now was used and tested good. I took a short video and posted a datalog to show what it's doing whenever the speakers pop and such. You can see it's creating noise in my RPM, but I don't see a big change in voltage in the log though. It seems odd that at 6000+ rpms I'm only at 12.6V. Here's a short video. It's a lot worse in person because the video doesn't pick up the lighting too well, but it makes the speakers pop and all. You can hear them pop when I push on the brake pedal. I'm pushing it just enough to make the lights come on. In MegaTune the voltage is going down to low 11's whenever it happens. I know these video things suck, but it's a PITA to diagnose stuff online. http://www.tsnhosting.net/tristanlee85/voltage.wmv In the datalog is my transition from 2nd to 3rd and you can see where it spiked all the way to 9000 rpms a few times, but really I was only at 6400 or so. http://forums.plastikracing.net/files/rpm_spikes_137.png I've cleaned the grounds when I installed the new alternator (about a month ago). I used the wire wheel on my drill to clean the posts on the alternator and starter as well as cleaned the end terminals of the wires that bolt to the alternator and starter. I'm not sure what else to try. Quote Link to comment Share on other sites More sharing options...
AJ Posted July 24, 2007 Report Share Posted July 24, 2007 it looks like something is trying to turn on and pulling down a load and then kicking off or poping a circuit braker. i did find a bulletin on something but i need to know what your key looks like to tell you if it may help or not. Quote Link to comment Share on other sites More sharing options...
Vander Posted July 24, 2007 Report Share Posted July 24, 2007 How did you make those graphs with all of that information? What equipment/ software did you use? I like it! Quote Link to comment Share on other sites More sharing options...
tristanlee85 Posted July 24, 2007 Author Report Share Posted July 24, 2007 it looks like something is trying to turn on and pulling down a load and then kicking off or poping a circuit braker. i did find a bulletin on something but i need to know what your key looks like to tell you if it may help or not. The only thing really causing a load on the electrical system would be my amp, but it's a small amp to power my front speaker. It's like 50 rms x 2. I don't see how it would be a ground issue because in that datalog where the RPM spike occured, that system is grounded right to the negative battery terminal. I don't have any blown fuses. I can understand that applying the brakes will cause the lights to dim so I'm putting a load on the battery/alternator, but the popping sound coming from the speakers really has me going. I would say it's in my audio wiring, but I haven't touched that wiring in a very long time and it's routed very neatly and secure. When the speakers pop, the lights dim as well so... I don't know. It started happening as of about 3 days ago out of no where. Quote Link to comment Share on other sites More sharing options...
tristanlee85 Posted July 24, 2007 Author Report Share Posted July 24, 2007 How did you make those graphs with all of that information? What equipment/ software did you use? I like it! That's a datalog from my standalone ECU software (MegaSquirt). I happened to be logging and doing a WOT pull when I noticed 2 different time when accelerating my car missed. I though I might have went lean in a few spots and detonated, but it was just noise in the RPM signal cause it to jump real high and inject a lot of fuel for a split second. Quote Link to comment Share on other sites More sharing options...
AJ Posted July 24, 2007 Report Share Posted July 24, 2007 you can do a fuse test, start pulling fuses on everything you don't need to keep the car running. when the problem stops you'll know where to be looking for the problem. Quote Link to comment Share on other sites More sharing options...
Dave1647545494 Posted July 25, 2007 Report Share Posted July 25, 2007 this might sound kinda basic, but did you check the battery first before you did anything else and make sure it was good... your also going to want to recheck that alternator 12.6V is battery voltage you should see 13.5v to 14.5v all through the rpm range.... Quote Link to comment Share on other sites More sharing options...
tristanlee85 Posted July 25, 2007 Author Report Share Posted July 25, 2007 I'm going to go get a new alternator and see if that fixes it. The one that's in there tested good, but it was used with an unknown amount of miles on it. Quote Link to comment Share on other sites More sharing options...
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