93 Camry Ignition problem...

You are sure it turns over , the rotor moves and it fires the bulb, so it is not the timing belt. I would guess the coil, but it could be just shorting from oil leaking past the O ring allowing nightime condensation to short the coil. First I would clean the coil with denatured alcohol on a Clean White rag and spray electronics cleaner with a extension tube to get behind the coil. Shorting coils are common on coil under distributor cap models. It is common to short when humid or rain after sitting all night, running bad till it is let sit with a hot motor drying it out for up to 1 hr. Your new cap may not fit right, do you have the cap to distributor rubber gasket? It is a seperate 12$ item the manual says to replace. I had those issues on a 91 because of a loose cap and ditry coil. Now it is fine for 1 yr+. The cap must be Tight to not allow in air, shake it if it moves it is loose. After cleaning a hair dryer may help to dry out moisture. Don`t use wd40, Use Electronics Cleaner and not Rubbing alcohol, rubbing Alcohol contains a lubricant. If it works and coil was black with dirt it is your O ring, but it may be fine for years as removing the coil means removing the distributor. You did check more than one plug wire. let us know if it helps.

I'm assuming you took a loose spark plug, attached it to the plug wire and held the ground end of the spark plug on a good ground while cranking the engine. Can you borrow a new plug wire from a shop you're friendly with? (Almost all shops will have odd wires laying around.) Or take a known good one from a different engine to use for a test. Use the known good wire and repeat the procedure with the loose spark plug. Still no spark, check the resistance on the coil, I suspect you have a bad coil or coil problem from your description. There should be very low resistance (could be less than 1 ohm) on the primary side and 10K-15K on the secondary side. (These are approximates, but the relationship should be very low on primary and very high on secondary, if not then there is an internal short and coil won't produce enough voltage for good spark.) Before you replace coil I suggest you follow Mark Ramsley's guide and clean the coil and inside the cap. It doesn't take much of an oil film to make a path to ground as the resistance is extremely less than the spark plug and wire. Remember electricity is like water and will follow the path of least resistance. HTH, davidj92

You may not see oil , I did not in cleaning mine, but a white rag came up black and it fixed the issue. Pulling a distributor is work.

I noticed in the manual that there is an IGNITER in the ignition system, but my manual does not tell me anything other than how to change it. Could that be responsible in some way? I have no idea what it does, how to check it or what effect it would have if it was not functioning correctly.

See the Factory Service Manual Ignition section for igniter trouble shooting - that well may be the source of your problem:

I fitted a new coil today and all is well again for anyone interested. The guy at Toyota said he has never sold a coil before, so must be rare problem. Phill.

You are lucky and lucky you bought a Toy coil, as I found Autozone sells coils that are 1-2% defective, a Store owner told me this. Coil issues as actualy common on 88-91.