Hi,
The black smoke is likely the result of too much fuel. Since the fuel pressure is within spec, I want you to try something. Reconnect the vacuum hoses and disconnect the mass airflow sensor in the air inlet tube. See pic 1 below (number 5). See how it runs after that is disconnected. If there is no change, check to see if there is a change if you remove the air intake temp sensor (number 11).
If there is no change, we have two ways to go. First, check if we have injectors that have failed allowing too much fuel to the engine, or if the engine coolant temp sensor has failed and needs to be replaced. The ECT signals the computer of the coolant temperature. Based on that info, the computer determines the air/fuel mixture the engine needs to run its best.
If the sensor indicates -40F, the fuel mixture will be extremely rich. This won't set a code because as long as the computer is receiving a signal, it doesn't know if it is right or wrong.
Let me know your thoughts.
Joe
Monday, April 11th, 2022 AT 8:08 PM