I am going to get the code checked today. I am in the process of ordering the manuals though.
It appears that it would be the temp sensor. I will verify and compare to the 86 300E temp sensor.
Is HFM a BOSCH injection system?
Also engine harness???? My goodness, I have never heard of such a thing going bad, that has to be just a terrible repair, for it to be done right.

Thank you, and I will report back.

__________________
Regards

Mino Erhan Dallas, TX
'97 SL500 40th A.E.
'97 S320
'01 ML320
'85 Peugeot 505 SW
'07 BMW R1200RT
'74 Suzuki GT750