Lately I have been having issues starting the truck. The BATT is an Optima Red Top 16-18 months old. The ALT is stock. Wiring is stock. Additions have been E-fan (maybe 2 yrs), pillar pod gages, CB, fog lights are the "Baja" (Wal-Mart... yeah yeah) rectangular lights, radar detector, OEM CD6, 2x 150W KC Slimlites (only 1 bulb is working), Warn xD8000i winch (hasn't been hooked up for a couple months... never drained it dead winching)
I was having an issue where it seemed the fan clutch on the A/C compressor wasn't turning on, it would keep clicking and it would drain the power from the truck... literally killing the power. I don't know if this killed the battery or the ALT or not but I took it to Pep Boys a couple months ago and they checked the starting system and everything checked out OK. They said to have someone look at the A/C. Well, since then I basically have used 3-75 cooling... 3 windows open doing 75...
Lately though (and it's been hot here) I've gone out and tried turning the key to START and nothing! Absolute silence. Strange thing is, it'll do that for 2 or 3 turns sometimes and then start on the next. Well it didnt do it for me Sunday and I was stuck at Home Depot. I tried having someone jump me but only had the cables on for a min or so b/c they were in a hurry and nothing... still silent. I only had about 12.2V (using cigarette lighter meter). When the cables were on it was up to 13.something. Still no start. So I got it towed. It went to the shop and I called them this morning and they said it was ready... ok... Hesitant since I hadn't talked to them yet, they just knew it wasn't starting. But I went in and it started. It was reading 13.9-14.0V. They said the checked all the GND connections and cleaned them and hooked it up and everything checked out OK. The BATT, ALT and STARTER. Ok. So I head down the road, still hesitant... tried the A/C and the compressor seemed to turn on ok but Volts dropped to 13.5 so i wasnt trying that... back to 3-75 for the time being. Well, I went to work, the truck sat for 7-8hrs and it started ok. I drove about 15 mins and stopped at my g/f's place and was there for 3hrs. Went out to start and nothing!! Twice!! And the third time it started...
I already have a 200A H.O. ALT from Mr Alternator on the way with some 2GA wire and connectors and also an inline 200A fuse to run the cable to the BATT from the ALT. I took a multimeter to the ALT and then checked to the BATT and they were the same. So I figure it's not a wiring issue between the two. The terminals have been cleaned as well.
I disconnected the (-) from the BATT while the truck was running and the meter in the cigarette lighter started to drop from about 13.5-13.6 where it was when at IDLE to about 13.3 and then 13.2 when I got in to look. Does this point to the ALT???
I also was thinking maybe the BATT isn't holding a charge. When I shut it off tonight it read 12.8-12.7V. I went out in a couple hours and it was down to 12.4V and it did actually start. I can only guess what it'll be tomorrow...
Here is also a list of readings I took the other day using the lighter meter:
(Dome light was ON for ALL readings) (ellipses represent only a short time frame i.e. 15-30 seconds)
IDLE - 13.6
OFF - 12.7
ACC - 12.3
START - 10.6
IDLE - 13.6
IDLE w/ holding both windows UP closed - 13.4
IDLE LIGHTS ON w/ FOGS - 13.4
IDLE / EFAN (initial) - 12.7
IDLE / EFAN - 13.4...13.3...13.4
IDLE / HIGH BEAM / EFAN - 13.3
IDLE / EFAN / HIGH BEAM w/ KC (1 bulb is out) (initial) - 12.8
IDLE / EFAN / HIGH BEAM w/ KC (1 bulb is out) - 13.3...13.2
IDLE / EFAN - 13.4
OFF - 12.8...12.7...12.6
ACC / EFAN - 12.0...11.9
START - 9.2
IDLE - 13.3
2000-2500 RPM - 13.4
OFF - 12.8...12.7...12.6
So can any conclusions be made from all of this? Two seperate tests are stating that the BATT, ALT & STARTER are OK. Yet, obviously there is a problem here! Will these tests reveal if a BATT can't hold a charge? Do my readings conclude it's the ALT? What should the Voltage reading be? Can I expect a change in Voltage readings with the larger ALT? Might it just be BOTH are on their way out?