Stupid question, but does the gas gauge function when the key is in the accessory position? I'm scratching my head trying to figure out why my 10th AE won't start, and it occurred to me only recently to check the fuel level.

While I'm at it, is there a way to see if the fuel gauge works without a multimeter?

Hrm... And another question. I understand that an engine requires fuel, spark, and compression to operate. To test compression, you use a compression tester (I know about the 3 pulses, too).

How do you test fuel and spark?

I assume for spark, you'd pull the plug, leave it attached to the coil, and crank the engine, looking for a spark, right? And the same for fuel, only with an injector instead of a spark plug?

 

The gas gauge will only work when the key is in the 'ON' or 'START' position. A multimeter should be the only way to test it.

Yes, to test spark you can pull a spark plug and crank the engine over. You can also put a timing light on each plug wire and see if there's a signal.

To test the fuel system you can do a few things:

1) Test fuel pump voltage with the key in the 'ON' position & the fuel pump test connector jumped (yellow plug on passenger shock tower).
2) Test fuel pressure during cranking. Tee a gauge into the feed line (w/ fuel filter).
3) Remove the upper intake manifold & primary fuel rail. Tie the injectors so they're still plugged into the rail, and crank the engine over. Check that fuel sprays from the injectors.

All of this stuff will be covered in the FSM / Haynes manuals.