90 integra check engine light?... these things are stupid I know
 

i know these are pretty useless and are fairly general but i dont have the owners manual for my car and i was just wondering if anyone knew what will trigger the check engine light to come on in my 90 integra? i just want to know for my own sake

they're far from stupid. they usually relate to any type of failures that would cause emission and engine performance to degrade albeit obd1 was quite general and not too indepth.

anyways. there are a bunch of things that could set one off.
i forget what obd1 has in terms of sensors but i believe lean rich conditions, misfires, and any type of sensor opens will set a cel for sure.

most times they're emission related.

Your ECU is located under the carpet on the passenger side of the car. You have to pull back on the carpet to expose the ECU which is brass in color. There is a circular window on the face of it with red LED in it. This LED will blink and this is where you read your code.
To get the LED to blink, you must turn the car to the "ON" position but do not start it. The LED will blink with slow blinks and with fast blinks. If you have four slow and two fast, that is code 42.

0 - ECU
1 - Oxygen Sensor
3 - MAP Sensor
5 - MAP Sensor
6 - Crank Angle
7 - Throttle Angle
8 - TDC Position
9 - No. 1 Cylinder Position
10 - Intake Air Temperature
12 - Exhaust Gas Recirculation (EGR) System
13 - Atmosphere Pressure
14 - Electronic Air Control
15 - Ignition Output Signal
16 - Fuel Injector
17 - Vehicle Speed Sensor
20 - Electronic Load Detector
22 - VTEC System Malfunction
23 - Knock Sensor
41 - O2 Sensor
43 - Fuel Supply System
45 - System Too Rich or Too Lean
48 - Primarry Heated O2 Sensor
54 - Crankshaft Speed Fluctuation Sensor
61 - Primary O2 Sensor Circuit
63 - Secondary O2 Sensor Circuit
67 - Catalyst System
70 - Automatic Transaxle
71-74 - Random Misfire
80 - Exhaust Gas Recirculation
86 - Engine Coolant Temperature Circuit
90 - Evaporative Emission Control System Leak Detected
91 - Fuel Tank Pressure Circuit
92 - Evaporative Emission Control System Insufficient

- http://www.g2ic.com/tegtips/engine/13.html

when i changed my oil i spilled oil all over my O2 sensor... because its located right below my oil filter... could this be whats setting it off?

problem fixed... thanks guys!