Thread: Rad fans always on!

Hey I just finished my SR20VE swap. I noticed that after start up (running) that the fans were on and the engine was stone cold. I have a basic calum ecu. What am I doing wrong and why are the fans on?

Sounds like either bad roms or bad ecu. Put in a stock ecu and see if it still does it.

bad rom chips

What coolant temp. sensor are you using? Do you have any devices(Techtom mdm100, CMX, etc) you can use to monitor what the ecu is reading for coolant temperature?

chek the coolant sensor....change it , use the sensor of the other motor

The ecu is brand new/redone from Calum. I sent it off my self so how do I replace the rom or am I screwed. I have to send another ecu to him? Really don't want to do that, more money I don't want to spend! I changed all sensors over from my old motor that needed to be changed I believe? Is the coolant sensor under/around the intake on the passengers side? Thanks for the help

I know nothing of electronics and all of these programs your talking about. Shoot I can barely can use this thingamajiggy (computer) in front of me!

If you have the wrong coolant temp. sensor, it can falsely read hot causing the fans to stay on.
You actually have 2 coolant temp. sensors. 1(has one wire) is for the gauge in your dash. The other(2wires) is the one your ecu reads. They are both on the left side of your intake manifold if your looking it your motor from the front bumper.

Reburn the rom image on the chips and see if that helps..... you did buy a motes chip burner right? the basic is useless without a chip burner.

Sound like you forgot to plug in a plug.

I know which on it is call me. It is a plug under the Dist.

If you dont plug this plug in properly the ECU goes into fail safe mode.

Thanks everyone Andreas helped me find the problem! The fans are working properly now!!