New battery and alternator, still not charging properly

Just put in new battery and alternator after leaving light on and truck not starting after prolonged charging.

Autozone showed battery no good and alternator diodes not working in alternator so replaced both (alternator replacement with TRD sc is a PITA).

Start up shows 13.8 volts. While traveling it drops to 13.2 volts. As an aside truck feels down on power.

What should I look for?

 

Are you positive the loss of power is due to electrical issues? The voltages you posted are normal.

 

A dyno?

confirm, our charging systems are "smart systems". The voltages posted are normal, and will fluctuate based on load. If you need more voltage for say an AGM or lithium battery you will need a voltage booster, a whole thread on here for that.

 

The truck might feel down on power because the ECM is likely going through the lengthy relearning process after being wiped clean.
It’s in the programming phase for air/fuel ratio, ignition timing, driver input, etc.
This is normal if the battery is disconnected or replaced.

 

Belt tensioner?

 

Thats normal numbers so whats the issue?

 

Hopefully you did not put a autozone alt. on it. If you did pay the money for the core charge and keep your old one for a spare. They dont normally have problems. Reman alts arent that good.

 

They may not be bad, but they do fail. This sort of failure seems to be a little more commonplace on the newer 2nd gens, as it appears that Toyota cheaped out on quality parts utilization on the later models. Mine is currently bad and does not like heavy amperage draws at idle or while driving now. The issue is getting worse over time. I have to replace it, eventually. I'll probably do it soon.

 

https://www.tacomaworld.com/threads/2nd-gen-1grfe-alternator-rebuild-mud-cleanout.453757/

 

Lot of guys are doing the big 3 upgrade followed by a high output altenator pushing 200 amps at idle
https://www.tacomaworld.com/threads...-2nd-gen-tacoma-writeup-with-pictures.664674/

The factory altenator doesnt charge well at idle . You need some engine rpms for the battery to charge .

 

I appreciate the link, but this is not a diode issue, it is a voltage regulation issue. Besides, all the time invested into doing a rebuild on which is a 50/50 repair whether it will work or not is the equal to rebuilding an AC compressor. A rebuilt Denso unit is easily obtainable and for relatively cheap (about $170ish) so for the time and energy and questionable repairability results, I'd rather invest into a unit built by a legitimate brand.

 

OP specifically was told Diode went bad, that is exactly what I replaced in mine and it's still working great. For like $35 it's worth it to have a spare if his potential store brand one bites the dust.

 

Make sure you clean your throttle body to bring your idle back to normal

 

Were you having voltage drop issues under high electrical load as well?

Of course like I said it's not a Vatozone or O'really brand alternator. It would be Denso, and I've always had fantastic success using them as far as repair rate/ comeback ratio is concerned.

 

At the expense of a few ponies, I’m sure. The stock 130A alternator is properly sized unless you turn your truck into Hooverville

 

Thanks for all the replies!

Though no big stereo system it does have a trd sc which has the intercooler pump cycling endlessly even when turned off as well as a collection of fg road lights that are used on high beam.

Power loss was noticed prior to battery/voltage issues so I’m really not sure what’s causing that. The closest I can relate the problem to is a former 67 camaro with a plugged fuel filter that can’t get enough fuel. It may be the new 750hp ZL1 making everything feel slow but I don’t think so.

Truck is in shop to check electrical and get a fuel system flush. Thanks!!

 

Yeah that definitely has got to be something else causing the power loss then because the nominal voltage it hangs at while on is not going to cause that.

 

Fuel system flush?

 

Carbon deposit removal. Somewhat needed for a sc 4.0 with the pig rich TRD tune.

As a side note...shop shows me a rather large plugged up, in line fuel filter I forgot I had installed with the high flow fuel pump. Exactly what it felt like. Feels better now!