2014 5K iMac Temp sensors issues

[Sylvain60]

Hello

Since 1 year, I try to fix my 2014 5K iMac.
I bought this computer on eBay without screen and not working.
Now it run and I bought a screen too but it's running very slow with full throtling fan.

The cause, 3 temperature sensors are not working properly:
- CPU DIE PECI (no temp)
- LCD Flying LEAD (no temp)
- Timing Controller (no temp)

To fix it temporarly, I followed this guide, https://blog.viktorpetersson.com/2014/10/16/how-to-fix-kerneltask-cpu-usage-on-yosemite.html
to disable the kernel_task security which use 100% of the CPU and Macs Fan Control App to regulate the fan speed based on an another temperature sensor.

But the computer is still running slow, what I would like to do to fix this problem could be to emulate SMC Values for these three sensors.
Do you think it could be possible ?

By the way I am open to other solution even hardware, it's really hard to find the schematics for this computer.

Thanks in advance

 

[TwoH]

Your screen you’ve attached to it likely does not have the temperature sensor plugged into it.

 

[Sylvain60]

It has actually. I have tried 3 different ones.

 

[Merlin2408]

Hi. Did you get to the bottom of this problem. I’m having similar issues. Same 2014 5K i7 iMac, which from moment you turn on continuously runs the fan at full throttle and bottlenecks the cpu so the computer can’t do the simplest tasks efficiently. For example takes 10 seconds to loads ‘about this mac’ window. I have had moisture trouble once and the computer was sent away for inspection and to have the logic board ultrasonic cleaned. No issues with logic board were found which leads me to believe it’d one of the sensors. I’m happy to buy replacement and fit I just wanted to get some other peoples advice who are more knowledgeable than myself. It’d become a a bit of a matter of principle for me now to mend it as it’d immaculate condition and if it can be fixed I’m determined to do so. So please anyone that can advise I’m all ears! Thanks community.