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Alternator/Regulator affecting engine Temp reading

PostPosted: Thu Dec 09, 2010 7:38 am
by BillS
I have an odd problem. I have an Ample power alternator and Nextstep regulator that have been installed for many years and seem to be working correctly (I have an energy monitor to track operations). I have a switch in the alternator field circuit to manually turn off the alternator in certain conditions. That switch is on the engine control panel. Recently I noticed that when I turn the altenator on the engine electric temperature gauge jumps about 20 degrees. This only happens when the alternator is in full output mode. If the batteries are mostly charged and the alternator is putting out say 10 amps it does not happen. The system voltage does not change when this happens.

An alternator in high output could affect engine heating, but it is not truely overheating as the gauge jumps instantly when the field is turned on and drops instantly when it is turned off.

In a case like this I might expect a ground problem, but I have not found anything. All the wiring was very carefully done with oversize wires everywhere that are crimped and soldered. Again the alternator and regulator are charging correctly.

I would appreciate any ideas of what this could be or further tests to run to track this done.


Re: Alternator/Regulator affecting engine Temp reading

PostPosted: Wed Dec 15, 2010 5:06 pm
by Coulomb
These kind of issues are pretty much a given if the temp. sensor is a single wire with the engine serving as the second wire.

With a two-wire sender, the problem can be avoided.