Toyota Repair: 1990 Ignition, coil resistance, salvage yard

Question
Hi Ted,

What would cause a Camry to get no spark in the morning (later it's OK)?  Are there ways to test the igniter and ECU?

The water pump in my 1990 3SFE Camry went out and I had them replace the timing belt while they were in there.  (Could they have damaged anything doing this?)  When I picked the car up it ran OK and I went home.

The next morning the car wouldn't start (cranked but did not catch).  I pulled off the distributor cap and put it back on and it started up.  It didn't start again the next day.

This time I grounded a plug and wire and there was no spark. I checked the coil resistance and it was off so I had them replace the coil. By the way, the 1990 manual says the resistance should be .38 - .46 ohms and new coils, from 3 different manufacturers, are speced out at 1.5 ohms for a 1990 3SFE Camry.  Is this OK?  Next morning, same problem.

So far, the car runs fine during the day.  I live in Houston and suspect that it is warming up by the time I finish checking resistance and opening and closing the distributor.  Once it starts it has been good for the rest of the day and into the evening (until very late when I haven't driven it and it cools down outside).

I think that my next suspects are the igniter and the ECU.  Maybe the pickup coil in the distributor?  There is an ohm meter test for the pickup coil in the manual but I don't find any tests for the igniter or the ECU.  Are there any?

Please let me know if you have any suggestions to follow and if you can provide me with any ways to check the igniter and ECU short of exchanging them with another car.

Thanks Ted,
Kep  

Answer
The ECU rearely causes starting problems, the most common causes are the distributor(the parts inside it are not replaceable except the coil)there is no test for the igniter or the ECU except for terminal voltage checks at the ECU, this can be very time consuming, I would advise getting a used distributor from a salvage yard, probably around $50.00 it's a quick and inexpensive way to find the problem, make sure to replace the cap and rotor, this fixes the no-start 80% of the time.