Fuel gauge and temperature gauge issues

**Smalltownboy** · 04-28-2019

Sorry if I’m posting in the wrong spot but I have racked my brain in a number of different fashions to figure out my issue. I have a 2002 Pontiac Grand Prix GTP, and have previously owned a 99’SE. and if I remember correctly had the same issue with that car. The car in question is newly acquired and I have two nit picky issues that I cannot solve #1 the temperature gauge is not reading and when I plug an obd2 sensor into the computer monitoring port it is reading that it is getting a signal from the temperature sending unit but it is not showing up on the dash gauge, bad ground maybe? The needle never moves. #2 the fuel gauge is not working correctly. While sitting still with the ignition in the start/run position the fuel gauge will read the level in the tank, from what I can tell fairly accurately. But when the motor is cranked the gauge will rise until it is maxed out.

**Fivefingerdeathpunch** · 04-28-2019

From what I remember the temp sensor sends a signal to the PCM and the cluster. A bad sensor can still send it to the computer but not the cluster. It's a messy drop if you don't suck the coolant out of the lower intake but it's a simple swap.

**Bronco Boy** · 04-29-2019

Possible fuel sender issue for the fuel gauge problem.

**FordMan77** · 04-29-2019

Check the wiring to the temp sending unit. It gets baked over years of heat. My 00 GT is doing that now. Had to mess with the wires a bit to get the dash gauge to read.