Low voltage when starting
I'm trying to hunt down a problem with difficulty starting the car. It usually takes 6-10 seconds of cranking to get the car to start.
I measured the voltage at the alternator when starting the car and it's dropping from 12v down to 8v when trying to start. I measured the voltage at the battery terminals when starting the car and it's dropping from 12v down to 11v when trying to start. What would cause this kind of a difference? Do I need to worry about it or look in other places for a solution to my starting issues? |
Citron Stephen DeGroat Lugoff, SC (367 posts) Registered: 10/23/2007 09:43PM Main British Car: 1970 MGBGT V6, 7004R, AC, matching trailer 3.1 liter |
Re: Low voltage when starting
My first problem is with the battery voltage. Afully charged battery should have a touch over 13 volts.
The drop at the battery is not a problem to me. Don't know about the alt. Steve |
Re: Low voltage when starting
The battery was fully charged and officially had 12.6 volts. I had left it on a trickle charger for about 12 hours to make sure it was fully charged. I also had the battery tested at autozone and they said it was good.
Originally, I was grounding my battery to the body with a 4ga ground wire, and then grounding the motor to the body. I changed things around and ran two 8 ga wires right from the battery to one of the bolts that holds the slave cylinder to the bellhousing (Rover 4.2 + LT77 Trans). The car started dramatically better after making that change, but it's still not quite what I think it should be. Next I'm going to replace my positive battery cable with a new one. I'm still using the original 1977 cable and I think the copper might be corroding inside the line. Justin |