So my '74 2.0 FI has been running well. I do an oil change (warm), start it and run it for a short while, check oil, top it off. Next day I go to start it and it kicks a little but won't run. I checked to see if I perhaps knocked a vacuum line off, but everything looks okay. Any ideas? Where is the best place to start diagnosis?

Ok, I'll this to the top. I don't think the oil change in and of itself is the issue. A disconnected vacuum line probably won't do this either. Start with these fundamentals:

1. Is the fuel pump priming when you put the ignition on?

2. Are the injectors actually firing?

3. Are you getting spark?

Since you were underneath the car during the oil change it's possible you disconnected the connections to the pump. You need to narrow the possibilities down...

could you be more specific as to what "kicks a little but wont run" means? sounds like a dead/dying battery or bad lead/ground to starter. need more than kicks a little. its not a mule.

We really need a sticky for "non-starting car troubleshooting", and it needs to cover D-Jetronic, L-Jetronic, carbs, and bastard cars.

I can hear the fuel pump loud and clear when I turn the key, just like usual.
What's the best way to check the injectors?
Plenty of juice in the battery (Odyssey on a charger) but I haven't checked spark yet.

One thing to consider since the age of these cars is up there, is the ignition switch. I had one that was intermittently faulty. Car would crank fine but not fire off. Sometimes took 7 or 8 attempts to start before the engine fired off. I never would've thought that a bad ignition switch would act this way.....but, Brad Meyure figured it out. New switch and she fires off every time.

Also, with the ignition on, you should hear the fuel pump humming. Depending on the year of your car, the fuel pump may be in the rear of the car or installed in the front trunk on the newer cars. The hum is distinctive, so if you don't hear it, then trouble shoot the pump.

What type of fuel system? L-jet? D-jet? Carbs? Other?

Generically: Check for disconnected hoses and wires. Especially wires. On a D-jet car, triple-check the CHT sensor plug and the ground connections. Probably also a good suspect on an L-jet car.

--DD

if you are hearing "the Fuel pump running" i am guessing you are running carbs with an electric fuel pump. does the starter spin with any authority while the fuel pump is running? or, does it just kick in and not start? i am no authority on fi, but on start up, you wont hear the pump "run" it pressurizes the system and then waits for the car to start. does not run continuous at start up." more dis info please. i see you are in ct. pm me i would be happy to help. you aint far away.

I'm assuming (maybe I shouldn't) D-Jet since he said 74 2.0 FI. If fuel pump is running, then next step is to see if injectors are actually firing (is fuel getting to engine).

If you crank it repeatedly and can "smell" fuel, then it's probably either ignition-related or something else disconnected. Like Dave said, I would triple check the CHT connection and wire all the way to the ECU. A bad CHT or open circuit there will basically flood the engine preventing it from starting or only let it start briefly. Check the MPS connections as well.

If you don't smell fuel, then the easiest thing first would be to make sure your injector points aren't disconnected. Check the plug at the back of the distributor to make sure it's seated. If it is, then verify fuel is or is not getting delivered. You can remove an injector (leaving it still connected to the fuel rail) and put it in a jar. Crank the engine to see if fuel sprays into the jar. Or you can just pull a spark plug to see if it's wet or if there's at least evidence of fuel.

If problem not solved, then on to checking spark / ignition...

Yes, D-Jet. I'll try checking those connections and the "juice-in-a-jar" injector check.