Bad Grounds sc400
05-25-11, 09:21 PM
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Bad Grounds sc400
My car loaps really bad at stop lights when i press my foot on the brake pedal. Dash lights dim, radio cuts out. Its much better when i throw it in neutral instead of drive with foot on the brake. But its not killing my battery when i drive so i dont think its the alternator. Someone said it might be my grounds. Does anyone have pictures of where i can find the ground points. Also could i re route them somekind of way if its too difficult to get to? Thanks!
05-28-11, 02:09 AM
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i have the same problem, my dash lights up like a christmass tree and the dash dims, i thought it was my alternator becuase thats what happened before mine blew, i would like to hear what replies you get
05-28-11, 09:12 AM
#4
My car did the same thing when I first got it and every SC I've seen does it too but its a super cheap and easy fix.
05-28-11, 11:55 AM
#5
Actually the SC's do have really crappy grounds. If you're not very familiar with wiring and electrical I would suggest taking it to a car audio installer (not best buy) and asking them to add some new grounds to your tail lights, front and rear turn signals, radio and also a new ground from the battery to the chassis.
My car did the same thing when I first got it and every SC I've seen does it too but its a super cheap and easy fix.
My car did the same thing when I first got it and every SC I've seen does it too but its a super cheap and easy fix.
To find out if this is truly the problem, some probing with a voltmeter is all it takes...
FWIW, my SC has 205k+ and is 18 years old with no grounding issues...
Edit: I also prefer troubleshooting the problem first versus throwing money and parts at something that may not even be wrong to start...
05-28-11, 01:13 PM
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ive had the ground issue just follow the line back from the negative terminal and you will see where it goes on a 400 the line is right behind the oil filter mine was all corroded wouldnt even let the car start fixed it no issues even the flicker in my hid's has stopped.
05-29-11, 07:16 AM
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Thanks for the info guys, as a matter of fact now that you mention it, when I wiggled the the battery ground it got worse then wiggled it a little more and it was like the car was brand new again. It didnt last long but that tells me that there is a problem in that ground. Might have other bad grounds in other places also but i can tell that one is bad. I would say the battery was bad but the it always starts up strong.
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05-29-11, 07:49 AM
#8
I'm leaning towards the alternator/battery, but the first thing you should do is check to see if your power steering fluid is low and if so, check to see if the alternator is wet from the fluid leaking into it. I have replaced 4 alternators on some of my friends sc's over the past few months with the exact same issue's that you are having and they were all saturated with ps fluid. hope this helps
Last edited by iceman400; 05-29-11 at 07:56 AM.
05-29-11, 08:55 PM
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I'm leaning towards the alternator/battery, but the first thing you should do is check to see if your power steering fluid is low and if so, check to see if the alternator is wet from the fluid leaking into it. I have replaced 4 alternators on some of my friends sc's over the past few months with the exact same issue's that you are having and they were all saturated with ps fluid. hope this helps
05-30-11, 03:23 AM
#11
if you do notice some some fluid leaking in that area ...... you should
steam clean the area first to find out exactly where the fluid is coming from to make sure its not just one of the ps hoses. If its not one of the hoses and u are low on ps fluid i would pick up a new ps pump as well as the alternator and replace them both but only after the correct diagnosis.
steam clean the area first to find out exactly where the fluid is coming from to make sure its not just one of the ps hoses. If its not one of the hoses and u are low on ps fluid i would pick up a new ps pump as well as the alternator and replace them both but only after the correct diagnosis.
Last edited by iceman400; 06-03-11 at 06:08 AM.
05-30-11, 11:43 AM
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People saying the stock grounds are crappy are wrong.
I checked resistance and voltage drop across all grounds in my car and they all were great. I had to clean the ones under the UIM from water corrosion (washing engine bay) but that was it.
Adding more grounds would help, if it were having issues with grounds already and would be a band-aid fix in comparison to actually fixing the issue in the first place.
I checked resistance and voltage drop across all grounds in my car and they all were great. I had to clean the ones under the UIM from water corrosion (washing engine bay) but that was it.
Adding more grounds would help, if it were having issues with grounds already and would be a band-aid fix in comparison to actually fixing the issue in the first place.
05-30-11, 11:56 AM
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Sorry, Upper Intake Manifold.
UIM = Upper Intake Manifold
LIM = Lower Intake Manifold
TB = Throttle Body
FP = Fuel Pump
B+ = Battery Plus
B- = Battery Negative
MAFS = Mass Air Flow Sensor
AFM = Air Flow Meter
O2 = Oxygen Sensor
TPS = Throttle Position Sensor
MAP = Manifold Absolute Pressure
OD = Over Drive
I'm sure there are more, just a small list to help you out.
UIM = Upper Intake Manifold
LIM = Lower Intake Manifold
TB = Throttle Body
FP = Fuel Pump
B+ = Battery Plus
B- = Battery Negative
MAFS = Mass Air Flow Sensor
AFM = Air Flow Meter
O2 = Oxygen Sensor
TPS = Throttle Position Sensor
MAP = Manifold Absolute Pressure
OD = Over Drive
I'm sure there are more, just a small list to help you out.
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