Hi,
As far as draining the radiator, you only need to get it below the level of the sensor. The reason is to prevent coolant from leaking out when the sensor is removed. If you didn't do it that way, don't worry. It didn't hurt anything.
As far as the running issue, if the smoke is dark gray or black, that indicates there is too much fuel getting to the engine. The ECT can cause that by sending a false signal to the computer. By any chance, do you have access to a live data scan tool? If you do, I want you to check the ECT signal to confirm it is showing approx ambient temperature. Do this cold because that way the coolant should be air temp.
If that checks good, we need to check fuel pressure. If it is too high, that can cause a rich fuel mixture as well. Here is a link that shows how that is done:
https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator
If the pressure is within spec, then the next thing to check would be the catalytic converter to see if it is plugged. We will cross that bridge when we get to it. Hopefully, we won't need to.
If it is possible, record it starting and the smoke you see from the exhaust. Upload it for me to see.
Take care and I'll watch for your reply.
Joe
Friday, June 25th, 2021 AT 7:58 PM