Mudd
NAXJA Forum User
- Location
- Bethel Acres, Oklahoma
'88 XJ, 4.0, 4x4, auto, a/c, 100k
I don't use the volts gage in the cluster for voltage readings but as an indicator for when something changes. My gage has been reading left of 14, right of the red zone, and pretty much always in the same spot.
A few weeks ago the gage reading started to change. Sometimes in the red, sometimes a little higher, sometimes in the normal spot. With a DVM at the battery I was still getting 13 volts at cruise rpm and the a/c running. In another post 5-90 replied that 13 is o.k. under those conditions.
Fast forward another week and the gage is now spending a lot of time in the red. Last night on the way home from work the headlights were dim and the turn signal flasher couldn't even flash.
This morning I started to troubleshoot. The battery is a year old and has 12.2 volts static after sitting all night. After starting the engine, running at about 2,000 rpm, measured at the battery with a DVM I got less than 12 volts. Simple enough. Past experience tells me the alternator is not doing its job. Ran down to O'reilly and got a reman alternator.
The new alternator is only measuring 12.5 volts at the battery at 2,800 rpm. If I turn on the a/c and headlights I only get 11.9 volts. The cluster gage is still in the red, turn signal flasher is slow, power windows slow. I'm not getting my juice from this new alternator.
Last year I had inspected and cleaned the head to firewall ground. I did it again today. Last year I installed new heavy gage battery cables and added a cable from the negative post to the chassis. I had also replaced the small wire from the positive terminal with a heavy cable. I cleaned the battery terminals today. The belt is tight. I tightened it some more with no change.
The new alternator is putting out a little better than the old one but not by much. Maybe it's the new alternator? What else can I check? It seems to me that if you have a good battery and cables then an alternator spinning at cruise rpm and not producing significant charging voltage is defective.
Any ideas before I take it back?
thanks,
John
I don't use the volts gage in the cluster for voltage readings but as an indicator for when something changes. My gage has been reading left of 14, right of the red zone, and pretty much always in the same spot.
A few weeks ago the gage reading started to change. Sometimes in the red, sometimes a little higher, sometimes in the normal spot. With a DVM at the battery I was still getting 13 volts at cruise rpm and the a/c running. In another post 5-90 replied that 13 is o.k. under those conditions.
Fast forward another week and the gage is now spending a lot of time in the red. Last night on the way home from work the headlights were dim and the turn signal flasher couldn't even flash.
This morning I started to troubleshoot. The battery is a year old and has 12.2 volts static after sitting all night. After starting the engine, running at about 2,000 rpm, measured at the battery with a DVM I got less than 12 volts. Simple enough. Past experience tells me the alternator is not doing its job. Ran down to O'reilly and got a reman alternator.
The new alternator is only measuring 12.5 volts at the battery at 2,800 rpm. If I turn on the a/c and headlights I only get 11.9 volts. The cluster gage is still in the red, turn signal flasher is slow, power windows slow. I'm not getting my juice from this new alternator.
Last year I had inspected and cleaned the head to firewall ground. I did it again today. Last year I installed new heavy gage battery cables and added a cable from the negative post to the chassis. I had also replaced the small wire from the positive terminal with a heavy cable. I cleaned the battery terminals today. The belt is tight. I tightened it some more with no change.
The new alternator is putting out a little better than the old one but not by much. Maybe it's the new alternator? What else can I check? It seems to me that if you have a good battery and cables then an alternator spinning at cruise rpm and not producing significant charging voltage is defective.
Any ideas before I take it back?
thanks,
John