High fuel consumption and black smoke?

Hi,

Black smoke from the exhaust normally indicates a rich fuel mixture (too much fuel to the engine). However, there are several different things that can cause it.

There are several possible causes for high fuel consumption and black smoke from the exhaust of your vehicle. Some of the most common causes include:

Dirty air filter: A clogged, or dirty air filter can reduce airflow to the engine, causing it to burn more fuel than necessary and produce black smoke.

Faulty oxygen sensor: The oxygen sensor measures the amount of oxygen in the exhaust and sends this information to the engine control module (ECM) to adjust the fuel injection. If the oxygen sensor is faulty, it may send inaccurate information to the ECM, causing the engine to burn more fuel than necessary and produce black smoke.

Malfunctioning fuel injectors: Fuel injectors are responsible for delivering fuel to the engine in precise amounts. If one or more fuel injectors are malfunctioning, they may be delivering too much fuel, which can cause black smoke and high fuel consumption.

Dirty or faulty mass airflow sensor: The mass airflow sensor measures the amount of air entering the engine and sends this information to the ECM to adjust the fuel injection. If the mass airflow sensor is dirty or faulty, it may send inaccurate information to the ECM, causing the engine to burn more fuel than necessary and produce black smoke.

Since there are no diagnostic trouble codes present, that leads me to think it isn't sensor related. So, I would start by testing the fuel pressure. Here is a link that explains how it's done.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Next, if you have or have access to a live data scan tool, I need you to check something. With the engine running at normal operating temperature, check the short-term fuel trims and let me know what they are.

I attached the manufacturer's pressure specifications below for you. The second part of it is difficult to understand. What they are trying to say is the pressure should remain at 21psi or higher for five minutes after the engine is turned off. This is important to check because if you have a leaking fuel injector, the pressure will drop below 21 psi within five minutes.

Let me know your thoughts and what is found.

Take care,

Joe

See pic below.