Stop in for a cup of coffee

Good morning. So riddle me this? How would changing a 12 dollar water temperature sending unit immediately solve the hard start when hot problem my Jeep has/had?

for the last several months, I’ve been chasing a hard start problem with my Jeep. If I shut it off when hot and then came back within say 10-20 minutes, it would not want to start. Never tripped a single code in the computer.

When it finally did, it’d rev to redline. I’ve changed the plugs, wires, coil, throttle body, all 4 O2 sensors, finally I’d ordered new injectors and a new rail, those took forever to come in, they came in Friday, supposed to pick them up today from the stealership.

anyway, last week, my water temperature gauge went crazy and stopped working, that did finally trip a code. Water temp sensor/sending unit malfunction. So I went to the dealer Thursday, bought me the 12 dollar sensor and put it in on Saturday morning before drill.

Suddenly, the hard start problem is completely gone. It was still doing it as of Saturday morning prior to the temp sensor change out.
If sensor doesen agree with coolant temp, lets say its reading lower temp. It will richen mixture,some go full low,forcing extremely rich.
Others go hot, so not enough fuel to start in open loop. Easy enough to identify with a scan tool that displays live data. Im not big in unloading the parts cannon, without concrete evidence the part is faulty.