Engine/Transmission (1994 - 1998) Voltage Gauge Fluctuates Now!?

[GROBBINS]

Hard cold starting, replaced melted intake relay. Second one in two years. Shop I was referred to, couldnt tell me why my electrical (lighting) was surging. New batteries a year ago, passenger side battery was dead. Replaced and still surges. Truck runs great, volt meter sits at about 15v. then drops to 13v and then after a few seconds surges to 16v. and then back to 15v. Doesnt matter whether parked or on the interstate driving. I just dont want to have to replace the relay again or another battery. I had the alternator tested and it passed. Anyone please help me stop this money pit. thanks Gabe

 

[hsmith]

Not sure about it, but you may want to check the connector at the crank sensor, as it is an input for the pcm to control charging. Also check all grounds.

 

[CToney]

My voltmeter was fluctuating only slightly. It was bad grid heater relays. I changed them both and put new brushes in my alt and the problem went away.

 

[firemanmarc]

Tonight mine volt meter started dancing as well. Mine would just pull down erratically like the grid heaters were coming on. I pulled over and disconnected the feed wires from the batteries and it stopped. I am going to put a momentary switch in my truck to control the relays and get rid of all the sensors. The tractors I have with 6BT's are set up like that and it works great... I would pull your feed wires off the battery and see if that helps... Marc

 

[GROBBINS]

Marc, did you pull the relay feed wires?

 

[firemanmarc]

Hate to admit it... THought I was pulling the relay feeds, instead pulled the orange and blue wires that I assume are for the Shutoff solenoid. THose wires solved my problem on the way home. Had to put them back on to take son to school this morning(wouldn't start). Had no issues all day. So sorry to say I am off to search for the problem. Sorry for my mistake that might have mislead you. . Marc