I have installed aftermarket gauges to keep more precise readings on the car, the only question I have is this. I put in a coolant temp sensor where the original sending unit went, and just want to use it instead. But when I run the car the SES light comes on, reading the code it gives me the coolant temp fault. Can I just plug the original sensor back into the clip and stow it out of sight, Or does the car make any kind of adjustments to the tune using the original temp sensor as a reference? I have read post where guys put the aftermarket sending unit in under the #8 plug, but due to room or lack of that would be a complete PITA for me, but if I have to do it that way I will, I know I want my temp readings to come from the head and not the block..
Thanks

 

YES!! Correct ECT input is critical!

 

Thanks, I needed to know if the ECM used that for a reference for anything. Now it looks like its time to pull the starter, and wrestle the sending unit into passengers side head. DOHHH!

 

No need to pull trhe starter you can get to it from the top, but ALL of your closed loop fuling comes from the CTS. I ran my gauge from the passenger side and it is easy. OH I need a skillet and some bread so I can have me a sandwich for the post above me

 

CTS is one of the most imporntant sensors you have. Install aftermarket sending unit in rear of pass side head, right behind #8 header bolt. It's 12mm-1.5 thread. Dean

 

T it into the TB bypass line. Simple and quick.