A freinds Tacoma had the battery light come on so she went to AZ for a test of the charging system…They told her it was the battery. She got a battery and directly went to my house as I told her I will install it for her,
I checked the terminal voltage and it was 9.5V. When the engine was reved it did not change. It may have gone down a tenth or two.
I told her it looks like the alternator may be bad but and the battery. I proceeded to put in the new battery. I tested the battery and it was new this month and rang in at 12.65 volts. Perfect I cleaned all of the terminals including the positive on the alternator. There were not bad looking but I wanted to be thorough. It fired up and the voltage at idle was 13 volts. When she put the lights and blower on it dropped to 12.8. I told her there is still a charging issues and I dont know how the guy at AZ could have concluded the Alt was fine. I guess she trusts a guy with a uniform and a fancy looking machine over me. So, She wanted to drive it and see what would happen…The battery light would come on intermittently…by day 3 the battery was dead.
She limped to my house and I went to put in a new Alt thinking this is the root of the problem. After installation and jumping the battery to get it started it ran but again was only putting out 13 volts at idle. I cleaned the contact points good with a wire brush before I installed the new Alt. When reved it put out 13.2V. I know it should be up over 14 volts.
What is going on? I am looking for maybe a bad grounding strap. I need to remove the skid plate to really see if there is one below and Have not had time to do so.
I suppose the new Reman from NAPA could have a bad voltage regulator. But what are the odds?
The voltage drops from the Bat terminals to the AlT are almost 0. Same with the resistance. Milli ohms.
She has been driving it today and so far the light is not coming on. Could she have killed the new battery this early and that is what is going on now?
Does anyone know if there are engine grounding straps accessible from below. Thanks for ideas and shared experiences with this engine and issues.