Hi all im in need of some help. I have an 1989 yj 2.5l 5speed that the voltage drops with the head lights on. then as you add more to it, ie brake on turn signal lights and or heater and wipers. it will dim all the lights, and start to hesate and backfire and miss do to the lack of power.my sterio works fine trough this. there is a newish battery its a year old, new altinator and new headlights. also changed the computer under the dash do to it stalling out. it drives fine during daylight hours soon as night comes it acts up. it has done this for a year sence I bought it last September but has only been on the road for 6 months due to the computer going bad. im am lost when it come to wiring
check your voltage at the battery with jeep turned off..it will probably read in the area of 12.5-13 volts if everything is cool..then crank it and recheck..it should now read around 14 volts if alternator is working.your voltages may vary some from this but look for at least 12 volts not running and then an increase while running..if all that checks out then you at least know that you have the voltage available then you can start checking as described above
I had the exact same issue, and odd as this may sound, I disconnected the O2 sensor and the condition cleared up, still haven't replaced it yet either. Milage didn't drop, power, if you can call it that, stayed the same too...
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