HELP! need help with check engine light
 

ok, so i just came across a 1990 honda civic hatchback. 1.5 with a 5 speed. it was 800 bucks, clean and straight, with ok interior. motors good with 159k on the odometer runs smooth and shifts good, gets 41 miles to the gallon. my first issue is the check engine light came on. how do i get it to tell me what codes tripped? where do i look for the reset? second issue is the temp gauge is fluctuating, like it has an air bubble in the coolant system. what is the proper way to bleed the system? thanks for the help.

The check light is on the ECU itself. Pull down the carpet on the firewall on the passenger's side floor to see it. Turn key on but don't start. Observe blinking of the red LED through the window. It will blink one long sequence of from 1 to 20 blinks, pause and repeat.

To reset codes, disconnect the car battery (key OFF!) for a minute. Generally even without resetting, the CEL will stay off the next time the engine is started if the problem no longer exists, but the LED may continue to blink out the old code.

May want to change the thermostat it could be sticky and that's why the gauge fluctuates. To purge the system have the car on level ground, set heater knob on full hot, engine cold, take off the radiator cap and open the purge valve on the fitting where the top hose meets the engine (note: the thermostat is NOT in there; it is on the engine end of the lower radiator hose). Pour coolant into the radiator until it comes out the purge valve. Then start engine and add more if necessary.

ok, so..one flash long, followed by a pause, then 16 short quick flashes. any where i can find the list of codes?

Code 1 = O2 sensor circuit problem
Code 16 = fuel injector or main relay problem

Now reset/clear the ECU to see if both codes repeat. You only want to chase repeating codes.

--------------------------

Bleeding the cooling system:

1) Park the car on an inclined driveway with the front end higher than the rear.

2) Push the dash heater lever/knob to MAX heat.

3) Follow the directions in the diagram below (hint: the bleed bolt is located where the upper radiator hose connects to the engine):

Attachment 14846