Erratic I30 Temp Gauge

[bvehorn]

Hi Guys, I'm back. Did ya miss me? Haha! My last car was a J30 that I got a lot of help with here on NICO (thanks again, Wes!). Unfortunately, it was totalled when some jerk ran a red light in front of me. So I found a great, low mileage, I30 and have been driving it for the past 3 years without any problems. A few weeks ago, however, my radiator cracked and the temp gauge pegged at the top of the scale before I was able to get the engine shut down. (I was cruising down the highway in moderate traffic, not paying attention to the gauges.) I changed the thermostat before I found the radiator crack, but even with the new radiator my gauge was reading towards the top of the scale. Since then I've also changed the temp sender, water pump, hoses, and the gauge. I also verified the wiring using the FSM. So I finally bought a ScanTool adapter and hooked it up to my laptop, and verified that my coolant temp is a steady 185 to 190 degrees. Can anyone explain how the gauge actually works, with the sine and cosine inputs? Sometimes it reads "normal", and sometimes it seems to start at the mid-range position and go up from there. Bad ground on the flexible circuit board on the back of the instrument cluster?

[Q451990]

I really have no idea. I know that on the Q there are two temperature sending units... one for the ECU and one for the gauge on the cluster. Is that the case on the I?

If you don't have the factory service manual, you can view/download it at www.nicoclub.com/FSM/

Sometimes they do a good job of explaining things there...

Heath

[rblover]

temp sender is usually faulty or loose, i've seen the same problem on a number of nissans, its the sensor with the little one wire on it by the engine coolant sensor.