FI Systems
 

What is the difference between the 1974 1.8L and the 1975 1.8L fuel injection systems?

The air flow meter has an air temp sensor built in on the 75. The cold start valve is controlled by a Thermo-Time Sensor with a heating element, instead of an unheated one (which would more properly be called a "Thermo Sensor", but the other term is used in the factory manuals for all).

That's all I can think of off the top of my head. The differences aren't large.

If you consider the fuel pump to be part of the FI, then it is a different pump and is located in a different place (up front versus under the engine), and the hose layout is a little different due to that.

If you consider the smog pump and/or EGR to be part of the fuel injection system, those are not present in the 74s but may be there on some 75s.

The early 74 cars will have the charcoal cannister up front on top of the gas tank; mid-74 and later will have it in the engine bay. The hoses for the cannister system are run differently because of this. Again, not strictly part of the FI system, but related.

Hmm.... Anything else? Not that comes to mind.

--DD

The FI harnesses are different and not interchangeable, because of what Dave mentioned.