"My question was would impedance at block ground basically render the ect sensor inoperable thus giving me a voltage reading with minimal resistance?"

No

"Or if the block ground I'd bad (side of block), will the voltage be zero @ 13 with same circumstances as above. "

No












My question to you was a request that you verify my understanding of how you checked the wiring from the ECU to the sensor in more than 6 words. Once I went round and round for hours trying to help a guy trace this circuit before learning he was measuring pin 13 on the wrong computer. Six words don't always bridge the gap. Seeing 4.2V at pin 13 with the sensor connected says the sensor is open circuit, wrong type, or the wiring is not really connected.
--
Art Benstein near Baltimore

Sometimes, the good you do does you no good. -Dr. Phil's way of saying no good deed goes unpunished.