MGL Avionics User Forum

The Westach 399S9 temperature sender has been working fine for about 7 years. But now when I increase the engine RPMs above 2000, the oil temperature immediately jumps from 95 C to 175 C or higher. When I lower the RPMs below 2000, the temperature returns to normal. Has anyone ever seen this before? Sounds like maybe some electrical interference from my magneto or Plasma III electronic ignition?

When all else fails, read the manual. I missed the part that said the ground for the E-1 must be connected directly to the engine block and not shared with any other electronics. After I hooked it up that way, everything works great.