I bought my 88 Z24 2.8L today... i immediately noticed that something was not right with the charging system... my initail thought was the battery not holding a charge, replaced that, and still had trouble... it was very hard to start due to a slow, weak turn, like a dead battery... since i had a new battery installed, i ruled that out and assumed alternator... i checked it by starting the car and removing my positive battery terminal... the car started idling very rough, like the alternator was running, then shutting off and kept cycling back and forth simultaneously.... i checked the fuse for the alternator, and noticed a 10AMP was installed when it called for a 20AMP fuse.... replaced the fuse with a 20, and tested again... this time when i removed the battery terminal it kept running fine... could this have fixed my problem, and if so, how??? thanks -DAVE

First u should have checked the alternator with a multimeter to ensure it was showing at least 12.5volts or higher typically 13.5-14 volts.Second being the battery is new yes rules that out as a issue.I would recommend checking it as stated to verify the voltage coming from the alternator and the battery should show the same voltage as the battery while the car is running.Next clean all the ground wires for the battery is a good idea.I find it strange to have a lower amp fuse on the altern but,since u changed it to what it should be that's good.Once u verify the voltage at the alter being in the range above if it is below 12.5volts I would replace the alternator,and make sure the tension on the belt is correct I know it has a belt tensioner but,the belt may be old or stretched and may need to be replaced,based on ur visual check for cracks or too much play.If u have any further ?sss just ask and if I left anything off or something I just over looked may others add or correct me.That is where I would start and congrats on ur oldschool ride,glad to see u have interest in the old js.

you could have made things worse, as far as your idle goes you need to start the car, put it in drive and hold the brakes till the fan cycles on and off 2 times, then turn it off then restart it and do the same thing till it cycles on then off again, turn car iff then on and repat one lst time and your car will have relearned the idle and won't be so rough for you., as far as other problems if you have problems startting after a new battery look at the starter and wiring

the rough idle problem only occured when i disconnected the battery terminal to check the alternator.... otherwise the car idles perfectly... i just find it weird that after i changed the fuse to the correct 20amp, the alternator seemed to be funtioning properly when i disconnected the battery terminal... oh and by the way its a 5 speed