Identify parts on 4.3L

[DWABoat]

CSR tech guys,

I am new to fuel injected engines. Been with carbs until now. I am asking for help identifying the various sensors plugging into the throttle body. I really need to know what they are and what they do and if they should be changed as routine maintenance. Asking a lot, I understand. I can easily look at a diagram, but that would not bring the wisdom with it!

Any educators out there?

The two pictures attached are from a 2001 Mercruiser 4.3L EFI.


At the 4o’clock position, I know the black sensor is the Idle Air Sensor. Don’t know much about it, but the name.

This picture is of the flame arrestor.

 

[370Dancer]

Post your serial number, or better yet, enter it into marineengine.com and you will get exploded parts diagrams, identifying all these components.
I am only EFI, Multi-port injection, so no carbs at all.
IAC=Idle Air Controller = kind of an automatic throttle at idle, opening and closing an air intake "hole" instead of opening and closing the butterflies on the carb throat. The ECU is calculating how much air needs to come into the engine to maintain the correct fuel/air mixture.
I'm going to guess that the thing on the Flame arrestor is a mass air flow sensor, but I could be wrong.

For instance: https://www.marineengine.com/parts/...m-262-v6/0l012009-thru-0l618999/throttle-body

 

[Espos4]

The sensor on the flame arrestor is the “intake air temperature sensor”

FYI you have “TBI” or Throttle Body Fuel Injection

Basically 2 large fuel injectors that sit above the throttle plate.
There is also a throttle position sensor on the throttle body and a MAP sensor on the intake manifold (located just above the right side fuel Injector in your picture)

The IAC motor is the most common failure. The other sensors do not routinely get replaced.

That system doesn’t use an airflow sensor.

The fuel flow is determined by RPM, throttle position, coolant temperature, and MAP sensor inputs.

 

[DWABoat]

Thanks. That is a great start. Lot if things I got figure out as I transition from a 1989 engine.