Engine/Transmission (1998.5 - 2002) charging problem

[blee031]

Im only getting 12 volts off the alternator I replaced the batt's in febuary of this year just rebuilt the alternator thinking that was the problem.



it has been a slowly degrading since the batt's went bad during the winter.



im thinking it might be the pcm can it be REFLASHED or dose it have to be replaced.



also dose anyone have a DBRIII in the Tacoma Seattle area that could help me with some of the tests



Thanks for the help



1998. 5 Quad Cab LB, DTT trans, van aaken, 4" ext

 

[WestTN]

12 volts is the nominaly sytem voltage. Your batteres, or alternator could be bad, since you stated you only had 12v in Februry. I am asumming this would be with the engine running. In cold weather the system voltage couldbe in the range of of 14. 8 volts down to 12. 0 in V depending on whether the the engine was running . This range is normal as it reflects the efficiency of the charging of the lead-acid battery.

 

[blee031]

it woud charg to 14volt while driving in february but the batteres would lose there charge in a few hours. and where replaced. With the new batteres it was all back to normal for a few weeks then I noticed that the battery voltage was lower than the usual 14volts when the truck was warm. IT has degraded since.



I have noticed if I charge the batteres out of the truck and install them the truck will hold what ever voltage the batteres had before start up. exaple I charged them to 12. 25 installed them started the truck after the grid heaters cycle ended the batteres wold have 12. 25 volts



sorry if i was unclear

 

[KNetherby]

In your wet region of the country I would clean or replace all the battery cables they can look good but be bad. Also check the big fuse under the hood. The truck can run with it being blown and not charge the batteries enough for restart.

Kevin

 

[blee031]

I figured it out it was the diode plate that the stator wire's go to. It was toasted didnt see it when i rebuilt it.



thanks for all the advice