I’ve been running alot lately trying to get my two karts very close in overall performance and feel – so collecting alot data basically. One engine (both are Rotax Sr) has a very smooth temperature plot in AiM Race Studio. This engine never deviates more than 3 or 4 degrees over a lap once warmed up. The other fluctuates – sometimes drastically – over the course of a lap and the plot is alway up and down. Now it does somewhat track the RPM plot, but the swing in temperature over a lap can be 15 degrees! And as the engine warms up, the greater the deviation becomes.
So has anyone else experienced this? What could be the cause? My first thought is thermostat or water pump. But honestly there’s so many other things it that could be, I’d like to hear from others before I start digging around.
Before you start digging around, swap the water sensors and leads to the gauges to see if the problem moves with the swap. Make note of the path the leads take to the gauge. Next, swap gauges between karts.
I agree with Tony, first step is to change the sensor and lead. Secondly, make sure that the RPM wire and the water temp lead are not wound around one another or zip tied together. I have seen this happen before and it seems to be a result of the frequency. Sometimes it works fine, sometimes it is mind boggling. Since it changes with RPM, I will bet that is your problem.