Koso temp sensors question

I am using the Koso dash and have a Lexus 1UZ engine. When I turn on the ignition the instruments say the water and oil temps are roughly 135 and 155. When the engine is stone cold. I called Koso, they asked if I extended the wires. I may have, that was a long time ago. Well, the sensors are resistance based, and the longer wires will return higher temp values. Is this a common issue?

I checked the SLC WIKI and it gives part numbers for senders. Do these have longer wires?

A.J.
 
I think you will have a hard time finding anyone using the Koso dash. Most modern dashes use either CanBus and/or OEM style sensors which are not overly sensitive to wire length (i.e. they typically are fed 5V and the dash reads output voltage).

I have considerable experience at work with Thermocouples. Using the *right* extension wire, correct plugs and doing cold compensation is critical. I have installations with 200' extensions that are dead reliable.

You could try taking one of the sensors out, checking all the connections. Soldering any connections. Perhaps using a heavier wire (say 18-20 gauge). In short, get it working correctly with a longer wire while you have it out to work on it.
 
I made this more difficult on myself as always. I have one large connector that the whole engine harness goes through. So if I pull the motor, I only have 1 wiring connection to worry about. Because of this, the sensor wires are much longer than they should be. My ecu uses different sensors, and they're accurate, so that's not an issue. I'll probably just offset the Koso limits so the warning lights come on when they should, even though the values won't be accurate. Thst will buy me some time until I decide on a better solution.
 
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