Hi guys I've got a D51 at work that I'm working on where the voltage Guage spikes and pegs out even with everything electronic on in the cab. I took off the alternator and had it tested and it tested good so I'm curious if anybody else has run into this problem and if so what's the cause and fix???
Is your machine a D51-24? I assume it is based on year, but assumptions sometimes get me in trouble. Is the volt gauge similar to below?
It's a D51pxi and yes that's what the Guage looks like. I took the voltage from both batteries while it was running today one was 14.0 the other was 14.3 and then took the alternator voltage and it was 28.4
Komatsu specification for engine running system voltage is 26v to 30v, found in service manual. D51-24 does have a code for high voltage CA442, which will trip when engine controller sees 36v or above. If the 28.4 you are seeing is fairly constant and not jumping above 30v, in my experience there is no problem with the charging system.