temp gauge drops when shifting

[wilfonzo]

just like the title says, whats it mean?

[benemorius]

If I understand you correctly, it usually means that the temp gauge sensor is loose. It's not the one that the ecu uses, but a separate one. I'm not sure about the dohc, but on the sohc it is on the bottom radiator hose. Play with the connector and see how it affects the temp gauge.

[wilfonzo]

ive got it fixed, there are three "coolant sensors (each are actually called something diff)" the one you speak of on the bottom hose is for the fan, mine is no longer conected because i use that fan as a second cooling fan, the is a red sensor on the intake mani, that is the one that sends the signal to the computer, ie making your car run rich if the sensor is crappy i also found out if there is a short in this sensor it will blow the main fuse, the 20$ one. and the third sensor the small black one with a single prong that looks like it is nailed on, when the sensor is attatched and detatched enough this will become loose giving you a false reading on the gauge, and making it drop while shifting because of the movement of the car

if any of this is incorrect please correct me

[benemorius]

Obviously you have the important parts correct since you got it fixed.

You may wish to double check me as I am calling this from memory, but I believe that there are only two sensors. The one on the bottom radiator hose is the single-pronged one that you spoke of which feeds the temp gauge. The other one is the red two-pronged one on the intake manifold, which feeds the ecu. 240s don't have electric radiator fans, so unless yours has been converted to electric... well, something doesn't quite add up. You should have the electric fan for the a/c condenser, and the fan bolted to the water pump for the radiator/engine cooling.

[wilfonzo]

yeah my ac is gone and the fan is now on the radiator and i bought another electric fan so both of them are hardwired and not on the fuel pump wire like it used to be because it was blowing the ign switch fuse.... but everything is a-ok now that i bought the 10$ sensor