Low Voltage? Low Idle?
Thread Starter
Teching In
Joined: May 2010
Posts: 11
Likes: 0
From: Toa Baja, Puerto Rico
Low Voltage? Low Idle? First Issue/symptom:
when the car is first turned on voltage starts out pretty high, past 13 measured about 15.5v at the batt.
as soon as car warms up for some time voltage drops to 13 and when in D and stopped voltage drops to just before red. Goes to almost 13 or halfway between if you give it gas or put in N or you raise revs.
Replaced battery because it tested bad....still same issue...replaced alt still same issue.
I just recently got the car with mods in sig. The engine was transplanted from a 99 T/A since the original hydrolocked.
I also noticed when car warms up in D and stopped car idles exactly at 500rpm according to tach, which if i understand correctly could be around 400 rpm or maybe less realtime? And in N goes to 600rpm on tach.
Could it be the idle or am i just grasping at air here? I will clean the MAF which was descreened and ported and TB.
The car runs perfect and quite smooth just this voltage and possible idle issue.
when the car is first turned on voltage starts out pretty high, past 13 measured about 15.5v at the batt.
as soon as car warms up for some time voltage drops to 13 and when in D and stopped voltage drops to just before red. Goes to almost 13 or halfway between if you give it gas or put in N or you raise revs.
Replaced battery because it tested bad....still same issue...replaced alt still same issue.
I just recently got the car with mods in sig. The engine was transplanted from a 99 T/A since the original hydrolocked.
I also noticed when car warms up in D and stopped car idles exactly at 500rpm according to tach, which if i understand correctly could be around 400 rpm or maybe less realtime? And in N goes to 600rpm on tach.
Could it be the idle or am i just grasping at air here? I will clean the MAF which was descreened and ported and TB.
The car runs perfect and quite smooth just this voltage and possible idle issue.
Teching In
Joined: Aug 2013
Posts: 19
Likes: 0
From: So Cal
I'm going to say it's a bad Alt. If you are seeing 15+ volts at the battery with a multi-meter, the alt is overcharging the battery. 14.2 to 14.6 is typical at idle at the battery with a properly functioning Alt. Wouldn't be the first time a replacement Alt malfunctioned out of the box. Good Luck.
