89 honda civic ignition/ecu help!
 

I recently had to have some head work done. After putting everthing back together the car ran well for about two weeks. Then the idle slowly started to get worse. Now the car will start but barely runs. The computer gives codes 4 and 16. Code 4 indicates a bad crank angle sensor. So I put a distributor from a junkyard on. It gave the same codes. I then bought a reman distributor. It gave a code 4 and 15. At this point I'm wondering about the ecu. I also checked the grounds and cleaned them good with no different result. The honda dealership says that the ecu rarely goes bad, and that they don't have a way to check it. I don't want to keep throwing parts at the car in the hopes it will fix it. Any suggestions?

Disconnect the battery first. Then unplug the ECU, and from the ECU plugs measure the resistance of the distributor sensors all the way back through the car wiring (which should be in spec, the same as measuring them at the distributor). Also measure resistance from sensor wires to every other pin (except the other pin of the same sensor), including ground -- should be infinite. If these checks pass, it probably is the ECU itself.

Code 4: Do continuity checks on the crank sensor wires running between the distributor and ECU.

Code 16: Check for battery voltage at the fuel injector connectors with the key in ON(II), and then listen with an engine stethoscope for clicking at each injector with the engine idling. Finally, do continuity checks on each injector wire running between the distributor and ECU.