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Hi everyone I have a 97 nissan sentra 1.6 (My mom's car) at idle fuel system is open loop temperature is working fuel trim is in the 3 so all looks good at least to me if I rev the engine car goes in close loop but once at idle it switch's to open loop. Ok so back story my brother over heated this car head cracked (water pump was leaking) . I replaced head and now car is running great no problems it's been 3 months since I fixed it now it's time to get it inspected I checked today and see I have 3 incomplete ( 02 sensor, cat, EVAP system) that's when I saw the issue with the open fuel trim . I'm thinking best thing to do is replace both 02 sensor maybe they got messed up when the car over heated the car runs great no issue I did notice that with open loop both 02 sensor 1 and 2 read the same when I idle I can see faster switching in sensor 1 I also looked inside the catalytic converter when I had it out and it was not broken or blocked . If anyone has any suggestions I would appreciate it thanks
I checked this morning before going to work . (Outside temperature was 37 degrees) ECT 41 degree
IAT 44 degree . By the way when the car reached 87degree it went closed loop but once it hit 107 degree it went open loop and stayed open endless I gave it gas .
At 186 degree ECT ,
IAT was 87 degree
Also IMAP was 11.7
I will back prob the 02sensors today and see if they are working
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