charging trouble ?

[DanaLittle]

I've been having trouble with my charging system. One week ago while driving home about 35 miles away my charging gauge in the dash went all the way over to the right past 18 volts. The battery was very hot and smelled real bad. When i got home I when to the auto store and bought a new voltage regulator and installed it. I drove around and dash gauge seemed to work fine it moved around a little more than normal. checked output with meter and it was 14. 4 to 14. 7 volts. Thought everything was ok until i started to smell battery getting hot again. Checked battery and it was very hot and venting fumes bad. Had alternator tested its within spec. Had battery load tested it ok. Put New Voltage regulator again battery still gets hot like its being over charged ? One place said the pcm controlled voltage ?? Any Ideas what is going on? I done want to have to buy a new alternator and or battery? any suggestions ?? sorry so long

 

[1stgen4evr]

charging

If you put a voltage regulator on, you don't have a PCM. You don't state your transmission option but I think the 91. 5 with non OD automatic would not have the Putrid Crummy Mistake aka PCM.



On the other hand, if you have Overdrive, someone has retro fitted a voltage regulator to your system and you may have something happening to the PCM which may still be intermittently involved.



If the alternator will overcharge, it is ok. If the battery was 'cooked' till it is low on water, that could be part of the problem you have now. Probably, you have not found the cause of the first voltage regulator failure. The chrysler voltage regulator was never real good. This can be elusive and expensive to cure. If you have a PCM and a voltage regulator, you will have to correct that first.



There will surely be others that jump in here. You and I are not the only one who has had charging problems.



James

 

[bmoeller]

One place said the pcm controlled voltage ??

Yes it does. Check/clean the connections on the battery, battery cables, alternator, and the connectors on the PCM also. Check all the grounds. Check for a good ground between the engine and body.

 

[DanaLittle]

I have a pcm behind the battery mounted on innner fender and a voltage regulator mounted on the firewall. Should i only have one and not both ? If the pcm controls voltage is there a fix ? my transmission is auto w/od. The battery was a little low on water but not empty? I had two differnt shops load test the battery and both said it was fine ? The battery looks really old. Could my problem just be the battery ? Two put a volt meter on the battery with truck running you can watch the voltage regulator move up and down with rpm. voltage stays in spec doing the but the battery still vents and gets hot ?

 

[DanaLittle]

I will check all connections and get back with results. Thanks for quick replys keep them coming

 

[cerberusiam]

Check your positive battery cable for corrosion in the wire that supplies voltage to the truck. If that connection is bad (it can corrode inside the battery post connector) the PCM "sse's" the battery as needing charged and cranks up the alternator output and overcharges it. It may also spike the voltage and your lights will periodically flash bright then go back to normal.



The 91. 5 and 92's listed the charging system as having a voltage regulator. My 92 doesn't so somewhere between 91. 5 and 92. 5 the regulator was phased out and the PCM took over charge duties.



Check ALL your battery connections and alternator connections and use dielectric grease on them to make sure you are getting a good connection.

 

[1stgen4evr]

volatage regulator and PCM

You should not have both. The fact that there is a seperate voltage regulator tell me that the PCM was bad and the 'fix' was the firewall regulator.



"voltage stays in spec doing the but the battery still vents and gets hot ?"



If the vlotage stays in spec, I would be thinking that the battery was giving up. Try filling the water level on the battery and see if that helps but all things considered, the battery is the cheapest thing you can do next.



"The 91. 5 and 92's listed the charging system as having a voltage regulator. My 92 doesn't so somewhere between 91. 5 and 92. 5 the regulator was phased out and the PCM took over charge duties. "



I have no experience with those in between years and can offer zero advise there. It has been my understanding that if you have OD, you have the PCM and I thought all those controlled the voltage output from the alternator.



James

 

[Moab4x4]

My experience with excess voltage has been caused by bad regulator ground.

The bolts holding the regulator to the firewall can develop the bad ground over time.



I just got to inspect a truck manufactured 5/91 and that regulator is either factory on the firewall or someone has done an "extremely" good job of taping the harness with factory cloth wrap. I think it is factory also because my '92 manufactured in 9/91 did not have the factory voltage regulator (PCM only ) and there are other differences:

The earlier truck didn't have the ASD relay or the AC relay where the '92 does and the harness looked quite untouched. (unlike mine )

The earlier truck did have a PCM by the battery, but it obviously didn't control as much.



If your voltage now is within spec I also vote toasted battery if filling it up and cleaning the connections doesn't help.

One question would be what is your battery voltage when you are not running? If it is lower than 11V or so I would wonder if one cell inside the battery shorted to another. This would in effect make a 10V battery or such and would overheat at "normal" voltages.



I have converted mine to voltage regulator and it is a little jumpy, but works fine.

 

[DanaLittle]

thanks for all the help. battery was bad. put a new one in and all seems ok now, so much for trusting the parts stores to test a battery. two shops said it was ok. after sitting out of truck all night it only had 4. 87 volts thanks again

 

[JLEONARD]

 two shops said it was ok

Yes. I tested my battery once with the battery tester at my son's shop. Tester said it was good, but it didn't have enough to spin the engine over.

New batt solved the problem.

I do not trust automotive battery testers. Guess you learned that too.

Jay

 

[mysteryman]

charging problem dfix/test

James is correct "If you put a voltage regulator on, you don't have a PCM"



do you haul a trailer???? if you ran your running lights threw threw the truck harness it may have melted some of the circuits together when it got hot... ...

If you have a bad short or if you have a diode in the alt. that is shorting out it can cause what you described... ... .



A shorted battery cell can also cause this. One way to find out for sure is to disconnect the alt wiring . Then run a jumper cabal from the big post on the alt to the battery... there are 2 more terminals on the alt and 2 terminals on the voltage reg

Run a wire from the 2 small alt terminals to each terminal on the reg. then from 1 of the small terminals on the alt run another wire to the + battery terminal. . , Make SURE THAT THE REG IS GROUNDED TO THE ENGINE. Failing to do so will blow the reg!

Now start the engine and put a volt meter across the terminals and read the voltage.

It should read 13. 5 to 14 volts. If it is higher it is the alt or the reg or the battery.

. If it is normal the problem is in the truck harness... . Check at the h/light switch for burning or melted plastic... If you have smelled a burn smell in the truck at times while driving that is most likely what it is and it was caused by trailer lighting pulling too much voltage or shorting..... Never ever run the running lights for the trailer threw the main harness !!!!!

I've been having trouble with my charging system. One week ago while driving home about 35 miles away my charging gauge in the dash went all the way over to the right past 18 volts. The battery was very hot and smelled real bad. When i got home I when to the auto store and bought a new voltage regulator and installed it. I drove around and dash gauge seemed to work fine it moved around a little more than normal. checked output with meter and it was 14. 4 to 14. 7 volts. Thought everything was ok until i started to smell battery getting hot again. Checked battery and it was very hot and venting fumes bad. Had alternator tested its within spec. Had battery load tested it ok. Put New Voltage regulator again battery still gets hot like its being over charged ? One place said the pcm controlled voltage ?? Any Ideas what is going on? I done want to have to buy a new alternator and or battery? any suggestions ?? sorry so long