Need opinions on electrical problem

[Kinch]

I have a '95 4.0 sport with about 138,000 miles. About 4 or 5 days ago the amp gauge starting acting weird. When idleing with lights/ac/radio and such on the gauge dips down to 12 the little white line right before the red and even when driving doesnt go all the way back up to where it is 'supposed' to be. Just got it back from getttin a new alternator and new battery still doing the exact same thing :doh: ....any body have any ideas? Thanks

 

[jneary]

the charging system is controlled by the pcm. maybe that is starting to fail. you may want to double check your battery terminals and grounds first.

 

[90Pioneer]

Try cleaning the connections on the plug that goes into the alternator (not the charging cable).

 

[keith haw]

Not to hijack the thread but my 87 is doing the same thing... Have replace/upgraded the battery and alt cables. Have a new red top battery and new alt. Also have cleaned all the grounds I can find. Where is the pcm located? Is it the main computer?
Keith

 

[Kinch]

Keith was forced to take mine to the dealership but i will let you know what they figure out with myproblem in the next couple of days. Who knows it may apply to your problem as well or maybe point you in the right direction.

 

[keith haw]

Thanks Kinch... I've been chasing this around along time. Getting tired of having to hold the idle up at night when stopped with a/c,lites on.
Keith

 

[jneary]

the pcm doesnt control the charging system on the 87-90's

 

[jneary]

the pcm doesnt control the charging system on the 87-90's. for that i would check the charging voltage at the alternator, and compare it to the gauge reading. if the gauge is off it is probably bad. common on the earlier xj's

 

[Kinch]

had voltmeter on battery ....gauge was right