Voltage Gauge Behavior -M998

[NJPShorelife]

Just replaced the EESS, glow plugs and 60 amp alternator. Truck finally starts up like a champ! Though bizarre issue is the voltage gauge. Replaced items, stated up for first time ..great....gauge was low yellow, slowly building to mid and stayed.... at idle sits mid yellow and sits mid green when rpms go up...revving or driving.
Prior... Just as the alternator started to fail, there were a few minutes of huge electrical spikes maxing out the red zone before I shut it down. Could this have messed up the voltage gauge itself???? I installed everything perfectly, vehicle has Kascar grounding harness. Truck runs and restarts great now. Any operating details I'll share to help with troubleshooting. Not sure how delicate these gauges are. Just from the dash paint I can tell this voltage gauge has been replaced before. Any thoughts.... I'm listening.

 

[SublimeMudTime]

Just replaced the EESS, glow plugs and 60 amp alternator. Truck finally starts up like a champ! Though bizarre issue is the voltage gauge. Replaced items, stated up for first time ..great....gauge was low yellow, slowly building to mid and stayed.... at idle sits mid yellow and sits mid green when rpms go up...revving or driving.
Prior... Just as the alternator started to fail, there were a few minutes of huge electrical spikes maxing out the red zone before I shut it down. Could this have messed up the voltage gauge itself???? I installed everything perfectly, vehicle has Kascar grounding harness. Truck runs and restarts great now. Any operating details I'll share to help with troubleshooting. Not sure how delicate these gauges are. Just from the dash paint I can tell this voltage gauge has been replaced before. Any thoughts.... I'm listening.

Hook up a multimeter to the batteries while its running.

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[cajadao]

did you adjust the alternator output? i might be the case it needs a little more output.

 

[infidel got me]

The new alternator may have just been settling in-- voltage reg. charging, batteries back on line. Electrics do strange things some times. Do keep an eye on VOLTAGE SPIKES--- an over charging system will cook, burn, fry, melt all your new parts you just installed. Double check/clean all connections and re-check charging system with a volt meter as mentioned above.

 

[papakb]

You can read the alternator output/battery voltage on pins E and F of the STE-ICE connector. The voltage adjustment on the 60 amp alternator is located under a hex plug near the wire connection cover on the top of the alternator. The adjustment is done with a phillips head screwdriver and is backwards from what you'd expect. Clockwise LOWERS the output, Counterclockwise INCREASES it. Be careful when removing the protective cover on the alternator, there isn't much clearance there and a lot of power. You definitely don't want to short it out. The gauges are lowest bidder products and are notoriously bad. Use a good voltmeter directly between the large output stud on the alternator and ground. Adjust the output for 27-28 volts. A normal lead acid battery is 12.6 volts with the engine off and charges at 13.4 volts. Maintenance free batteries charge at a slightly higher voltage but 27-28 should be fine. The small line on the voltmeter face is (or should be) 28 volts.

Kurt