hi i have a 1991 s5 n/a rx7, and i found out that my temperature unit is not grounded, i figured this out by putting the ignition to on but not turning the car on and the Buzzer will always buzz in a few seconds after, as it was buzzing i grounded the temperature unit cable that leads to the radiator to the Negative of the battery and the buzzer goes away, Does this mean my coolant was never working bc of a bad ground connection, and could this mean why i am getting bad millage? ive been getting about 12miles a gallon which is not good, So should i ground the cable better to the radiator this time

 

That's not going to affect your fuel mileage, while new plugs and an air filter would.

 

Hey satch, since my radiator temp was always in the half point and been reading around that if its not working properly it makes the ecu think its always cool thus more fuel, but turns out that my radiator is broken from the side and im guessing that the coolant level sensor is broken, im still trying to find if anything is not working right

 

I think I misread your post but the coolant level sensor would be one of the causes for the buzzer to go off and not the sensor that supplies the temp gauge with the proper reading. The thermosensor is the sensor which reads the coolant temp and adjusts how much fuel to use upon startup and thereafter to a degree but it is independent of the sensor connected to the temp gauge. You could also check your pressure sensor according to spec as it plays a role in how the fuel injectors behave.

 

You were correct about the Air temp sensor having a role in how rich the car will run at as it was my mistake. So besides that and the Water thermosensor and Pressure sensor, also check the Air temp sensor in the AFM, and all of these can be checked at the ECU. And pull the vacuum hose off of the FPR while idling and check to see if there is vacuum present.