I just swapped a DOHC ZC into my 90 Civic Si. The motor I pulled was running and the ZC came out of a running car. The car won't start and has no spark. ECU show code 15 for ignition input signal. I got out the Helms and did the tests it called for and everything checks out. I have tried a known good ECU and get the same code. The strange thing is after cranking the motor I can pull out the key and the oil light, seatbelt light door open lights all stay on but are dimly lit. If I disconnect the battery for a few seconds and then reconnect it, the lights go out. When I have the cable off the battery I tested for voltage and something is drawing 11.5 volts. I must have a short someplace but where?

 

Check your main ground, DO NOT just eyeball them, redo them disconnect/clean/reconnect, dim lights indicate a grounding issue. 94

 

All grounds are cleaned and I sanded down to bare metal. Still have the same problem. It is an intermittent problem. The draw on the battery is constant though.

 

OBD0 or OBD1 ECU?

You may have two separate problems - igniter unit and ignition switch - test both.

If you reset the ECU, does code 15 return?

 

I think you may be right on having 2 problems. Code 15 comes back after resetting the ECU. I will check the igniter. The switch feels"loose" when you turn it, no clear click for each position.

 

Bought a brand new distributor and still get code 15. I have tried several ECUs. I have a Helms and did the tests to check "Ignition input signal". It passes the test. It says if the test shows voltage then test the ECU and I have tried a few of them. Next step is replace the ignition switch. I HATE just throwing parts at a problem but I am running out of options.

 

A bad ignition switch won't cause code 15.

Did you reset the ECU to see if code 15 returns?

 

You can test the ign. switch before you replace it.

You say you have a parasitic draw, that would be in amps not volts, use a 12V test light, [NOT LED type] to confirm parasitic draw, disconnect batt. neg. cable connect test light ground clip to batt. neg. post and the test light probe to the neg. batt. cable, [series connection] make sure everything is off and if the test light lights up, you have a parasitic draw
With the test light connected, start by disconnecting the power lead to the alt. to eliminate the voltage regulator as the problem, if not it, start pulling fuses one by one until test light goes out, when it does, you have found the circuit that has the drew, one by one disconnect any loads on that circuit until test light goes out, replace defective part, that problem is solved. 94

 

Reset ECU and code comes back after a few seconds of cranking. I am going to replace the engine harness next. I have another one that I know is good.