Cause and effect

Farmwithjunk · Mar 16, 2006

Let's say a voltage regulator is failing. It allows 16.2 volts into the system. Obviously, the battery suffers. (It's started to swell on one end, leaking at the caps, ect) Reg is 35 years old. It gets replaced tonight. Battery is getting replaced shortly after that.

My question. I've noticed a slightly higher reading on the voltmeter lately. That should resovle itself. I've also noticed slightly higher readings on the oil pressure gauge (electric "switch" controlled) and the fuel guage does some whacky stuff lately too.

Is any of this the result of 16.2 volts in a 12 volt system? (No ignition system to deal with. diesel engine)

Soundguy · Mar 16, 2006

Hey .. I think I say you on the ytmag forum....

It will depend if it is a resistance style gauge.. if so.. unstable voltage will effect readings ( most fuel gauges are resistance gauges.. ).

Soundguy

Farmwithjunk · Mar 16, 2006

</font><font color="blue" class="small">( Hey .. I think I say you on the ytmag forum....

It will depend if it is a resistance style gauge.. if so.. unstable voltage will effect readings ( most fuel gauges are resistance gauges.. ).

Soundguy )</font>

They are resistance type. Make 'em read high? Low? Off completely? Trying to explain some unexplainable phenomenon with the gauges lately. Oil pressure reads about 10 PSI higher than the last 30 or so years. Fuel guage jumps to full when first started, then drops to empty. Has new sending unit with ZERO effect. Never have spent much time chasing that problem yet. Voltmeter shows high. It is. 16.2 volts at the battery.

Soundguy · Mar 16, 2006

i would think all resistance gauges would read higher when system voltage is up. Some gauges may die..... just don't have the tolerance for the voltage..

Soundguy

KubotainNH · Mar 16, 2006

I agree that it would be higher because the voltage potential is higher. Most sending units basically change the resistance to ground using a single wire. I wouldn't think it would damage the guage unless it were to peg it continuously. It would have to burn the winding which would take alot and hopefully would burn a fuse 1st. If you are worried about ruining some of the electrical parts then I would disconnect the charging system until repaired and just keep the battery charged.

Farmwithjunk · Mar 16, 2006

Update;

I installed the new reg. Old one was toast. Found 1 spade lug bent side-ways. Not connecting to anything. I'll spend a few minutes tomorrow looking at the service manual. That'll tell me what was disconnected.

Voltmeter is back at normal. Oil pressure gauge is reading normal again too. Fuel gauge still not up and running. No voltage through gauge, but could still be a ground problem. Not sure yet.

Voltage after reg is 13.9 . That'll work.

Next step, get a new battery to replace the somewhat inflated one.

Soundguy · Mar 16, 2006

My bet on the bent lug, if it were an alternator, was that it was the equivalent of the #2 lug on a delco 10/12si model.. The remote voltage sense line. That line was hooked to the battery to sense the voltage drop between the alt output and the battery due to laod and length of wire. if you don't hook them up.. many 3 wire alts default to charge 'high'.. and that creates excessive charge voltage... sound familiar?

I've also seen fuel gauges die from excessive voltage. in most cases, the fuse is too high a value to go before the microscopic winding in the gauge or mechanism dies...

Soundguy