Charging/Alternator ?
 

'89 YJ, 258. I've replaced the belts, battery, and alternator. The
voltmeter stays in the 'red' unless I hold my foot on the accelerator.
Once the engine warms up (temp gauge @110+?), voltmeter stays close to
14. I know it's not a bad voltmeter reading because the lights get dim
when idling. Any ideas? Thanks, Dan

Re: Charging/Alternator ?
 

Same thing happened to me with my 91 YJ. Turned out to be the voltage
regulator which is part of the PCM. Required replacement of the PCM before
the problem was corrected. I'm pretty sure that all YJs and TJs have the
PCM controlled voltage regulars. Only way to fix it is to replace the PCM.
Sorry for the bad news, they're pretty pricey. If you have a check engine
light, there will be a code associated with it. My codes were 41
(alternator field), 42 (Automatic shutdown relay), 46 (Battery overvoltage).
I have the 4.0L FI engine so there may be some differences from your 258,
4.2.

Scott
"Daniel Paisley" <dmpazlee@webtv.net> wrote in message
news:25112-41BC2E90-23@storefull-3111.bay.webtv.net...
> '89 YJ, 258. I've replaced the belts, battery, and alternator. The
> voltmeter stays in the 'red' unless I hold my foot on the accelerator.
> Once the engine warms up (temp gauge @110+?), voltmeter stays close to
> 14. I know it's not a bad voltmeter reading because the lights get dim
> when idling. Any ideas? Thanks, Dan
>

Re: Charging/Alternator ?
 

Same thing happened to me with my 91 YJ. Turned out to be the voltage
regulator which is part of the PCM. Required replacement of the PCM before
the problem was corrected. I'm pretty sure that all YJs and TJs have the
PCM controlled voltage regulars. Only way to fix it is to replace the PCM.
Sorry for the bad news, they're pretty pricey. If you have a check engine
light, there will be a code associated with it. My codes were 41
(alternator field), 42 (Automatic shutdown relay), 46 (Battery overvoltage).
I have the 4.0L FI engine so there may be some differences from your 258,
4.2.

Scott
"Daniel Paisley" <dmpazlee@webtv.net> wrote in message
news:25112-41BC2E90-23@storefull-3111.bay.webtv.net...
> '89 YJ, 258. I've replaced the belts, battery, and alternator. The
> voltmeter stays in the 'red' unless I hold my foot on the accelerator.
> Once the engine warms up (temp gauge @110+?), voltmeter stays close to
> 14. I know it's not a bad voltmeter reading because the lights get dim
> when idling. Any ideas? Thanks, Dan
>

Re: Charging/Alternator ?
 

Same thing happened to me with my 91 YJ. Turned out to be the voltage
regulator which is part of the PCM. Required replacement of the PCM before
the problem was corrected. I'm pretty sure that all YJs and TJs have the
PCM controlled voltage regulars. Only way to fix it is to replace the PCM.
Sorry for the bad news, they're pretty pricey. If you have a check engine
light, there will be a code associated with it. My codes were 41
(alternator field), 42 (Automatic shutdown relay), 46 (Battery overvoltage).
I have the 4.0L FI engine so there may be some differences from your 258,
4.2.

Scott
"Daniel Paisley" <dmpazlee@webtv.net> wrote in message
news:25112-41BC2E90-23@storefull-3111.bay.webtv.net...
> '89 YJ, 258. I've replaced the belts, battery, and alternator. The
> voltmeter stays in the 'red' unless I hold my foot on the accelerator.
> Once the engine warms up (temp gauge @110+?), voltmeter stays close to
> 14. I know it's not a bad voltmeter reading because the lights get dim
> when idling. Any ideas? Thanks, Dan
>

Re: Charging/Alternator ?
 

You are describing a dirty battery cable.

I would be checking the ground side first, the cable goes to the engine
block and gets corroded there, then the next cable is a wire mesh one
that goes from the rear of the engine head to the firewall, this one is
most likely the bad one, but...

I also have seen the alternator bracket itself lose the ground. You can
check this by using a booster cable from the battery negative to the
alternator case. If the volts stabilize you have found it.

The other one that will cause those symptoms is a dirty connection on
the starter solenoid on the firewall. The alternator wire and positive
battery cable connect there and get dirty really easy.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Daniel Paisley wrote:
>
> '89 YJ, 258. I've replaced the belts, battery, and alternator. The
> voltmeter stays in the 'red' unless I hold my foot on the accelerator.
> Once the engine warms up (temp gauge @110+?), voltmeter stays close to
> 14. I know it's not a bad voltmeter reading because the lights get dim
> when idling. Any ideas? Thanks, Dan

Re: Charging/Alternator ?
 

You are describing a dirty battery cable.

I would be checking the ground side first, the cable goes to the engine
block and gets corroded there, then the next cable is a wire mesh one
that goes from the rear of the engine head to the firewall, this one is
most likely the bad one, but...

I also have seen the alternator bracket itself lose the ground. You can
check this by using a booster cable from the battery negative to the
alternator case. If the volts stabilize you have found it.

The other one that will cause those symptoms is a dirty connection on
the starter solenoid on the firewall. The alternator wire and positive
battery cable connect there and get dirty really easy.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Daniel Paisley wrote:
>
> '89 YJ, 258. I've replaced the belts, battery, and alternator. The
> voltmeter stays in the 'red' unless I hold my foot on the accelerator.
> Once the engine warms up (temp gauge @110+?), voltmeter stays close to
> 14. I know it's not a bad voltmeter reading because the lights get dim
> when idling. Any ideas? Thanks, Dan

Re: Charging/Alternator ?
 

You are describing a dirty battery cable.

I would be checking the ground side first, the cable goes to the engine
block and gets corroded there, then the next cable is a wire mesh one
that goes from the rear of the engine head to the firewall, this one is
most likely the bad one, but...

I also have seen the alternator bracket itself lose the ground. You can
check this by using a booster cable from the battery negative to the
alternator case. If the volts stabilize you have found it.

The other one that will cause those symptoms is a dirty connection on
the starter solenoid on the firewall. The alternator wire and positive
battery cable connect there and get dirty really easy.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Daniel Paisley wrote:
>
> '89 YJ, 258. I've replaced the belts, battery, and alternator. The
> voltmeter stays in the 'red' unless I hold my foot on the accelerator.
> Once the engine warms up (temp gauge @110+?), voltmeter stays close to
> 14. I know it's not a bad voltmeter reading because the lights get dim
> when idling. Any ideas? Thanks, Dan

Re: Charging/Alternator ?
 

He is lucky, Chrysler hasn't aborted the charging system yet on his 258,
he still has a 'real' alternator.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

reconair wrote:
>
> Same thing happened to me with my 91 YJ. Turned out to be the voltage
> regulator which is part of the PCM. Required replacement of the PCM before
> the problem was corrected. I'm pretty sure that all YJs and TJs have the
> PCM controlled voltage regulars. Only way to fix it is to replace the PCM.
> Sorry for the bad news, they're pretty pricey. If you have a check engine
> light, there will be a code associated with it. My codes were 41
> (alternator field), 42 (Automatic shutdown relay), 46 (Battery overvoltage).
> I have the 4.0L FI engine so there may be some differences from your 258,
> 4.2.
>
> Scott
> "Daniel Paisley" <dmpazlee@webtv.net> wrote in message
> news:25112-41BC2E90-23@storefull-3111.bay.webtv.net...
> > '89 YJ, 258. I've replaced the belts, battery, and alternator. The
> > voltmeter stays in the 'red' unless I hold my foot on the accelerator.
> > Once the engine warms up (temp gauge @110+?), voltmeter stays close to
> > 14. I know it's not a bad voltmeter reading because the lights get dim
> > when idling. Any ideas? Thanks, Dan
> >

Re: Charging/Alternator ?
 

He is lucky, Chrysler hasn't aborted the charging system yet on his 258,
he still has a 'real' alternator.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

reconair wrote:
>
> Same thing happened to me with my 91 YJ. Turned out to be the voltage
> regulator which is part of the PCM. Required replacement of the PCM before
> the problem was corrected. I'm pretty sure that all YJs and TJs have the
> PCM controlled voltage regulars. Only way to fix it is to replace the PCM.
> Sorry for the bad news, they're pretty pricey. If you have a check engine
> light, there will be a code associated with it. My codes were 41
> (alternator field), 42 (Automatic shutdown relay), 46 (Battery overvoltage).
> I have the 4.0L FI engine so there may be some differences from your 258,
> 4.2.
>
> Scott
> "Daniel Paisley" <dmpazlee@webtv.net> wrote in message
> news:25112-41BC2E90-23@storefull-3111.bay.webtv.net...
> > '89 YJ, 258. I've replaced the belts, battery, and alternator. The
> > voltmeter stays in the 'red' unless I hold my foot on the accelerator.
> > Once the engine warms up (temp gauge @110+?), voltmeter stays close to
> > 14. I know it's not a bad voltmeter reading because the lights get dim
> > when idling. Any ideas? Thanks, Dan
> >

Re: Charging/Alternator ?
 

He is lucky, Chrysler hasn't aborted the charging system yet on his 258,
he still has a 'real' alternator.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

reconair wrote:
>
> Same thing happened to me with my 91 YJ. Turned out to be the voltage
> regulator which is part of the PCM. Required replacement of the PCM before
> the problem was corrected. I'm pretty sure that all YJs and TJs have the
> PCM controlled voltage regulars. Only way to fix it is to replace the PCM.
> Sorry for the bad news, they're pretty pricey. If you have a check engine
> light, there will be a code associated with it. My codes were 41
> (alternator field), 42 (Automatic shutdown relay), 46 (Battery overvoltage).
> I have the 4.0L FI engine so there may be some differences from your 258,
> 4.2.
>
> Scott
> "Daniel Paisley" <dmpazlee@webtv.net> wrote in message
> news:25112-41BC2E90-23@storefull-3111.bay.webtv.net...
> > '89 YJ, 258. I've replaced the belts, battery, and alternator. The
> > voltmeter stays in the 'red' unless I hold my foot on the accelerator.
> > Once the engine warms up (temp gauge @110+?), voltmeter stays close to
> > 14. I know it's not a bad voltmeter reading because the lights get dim
> > when idling. Any ideas? Thanks, Dan
> >