Check Engine Troubleshoot - 1990 Sedan

ChrisBMacon

New Member
1990 Honda Civic 4dr Sedan, Manaul trans. Opinion on what may be causing Check Engine until I get it checked this weekend.

Only comes on when I hit 55mph at 2500 rpm.

All exhaust replaced. Resonator back.
New exhaust manifold.
New wires/plugs.
Cleaned pvc valve.
Cleaned O2 sensor.
Replaced all hoses and vacume hoses.
Temp sensors OK with fan kicking in at 190.
No oil burn/leaks.
Alt. 13.5 output.
The check engine came on before I went thru the replacements also and I didn’t have it checked.

Any thoughts what it may be only at 55mph?
 

AlaskaB16

DOING WORK!
Registered VIP
Are you aware the check engine light is actually giving you a code? Go find out what code it's giving you and then we'll have a better idea of what to check for. I'd give you a few guesses but that's all they'll be. You'd be surprised at what can actually trip a CEL and what the fix is. Could be just a loose injector plug not making full contact for example... Simple dumb solutions that a mechanic will charge you 5 hours of labor on.
 


ChrisBMacon

New Member
Update: Need suggestions.

The LED was blinking once, each 3 seconds. Code one references o2 sensor.
Removed negitive from battery.
Replaced o2 sensor.
Battery hooked back up.
Drove to work today, check engine came on again at 55mph.

Question; Do I need to perform another set in clearing the ECU memory? Checked the LED BEFORE cutting off the motor and it was blinking 1 time every 3 seconds.

????
 

b16lewis

New Member
Registered VIP
5+ Year Member
Was it a fast blink or a slow blink
 


b16lewis

New Member
Registered VIP
5+ Year Member
How does it act when you drive it hard, or is it only 55mph at 2500rpm. Because speed would only be one code and that is for the vss. I don't think this is a speed related problem. If you can post a little video of the cel. Because it can be easily misunderstood, not trying to question your ability but a clear insight will help us trying to help you
 

ChrisBMacon

New Member
b16lewis, question well taken.


LED blinked 1 blink every 3-4 seconds continuiously.

Car runs GREAT at cold start.
Car runs GREAT at low RPM after warm up.
Car runs GREAT at all RPM ranges.
Car runs GREAT at high RPM but threw code.


Update: Cleared the code this saturday. ECU did not blink at all after reset


Clearing ECU method=
Allowed car to reach moderate warm temp.
Cut car off.
Removed ECU/Emergance fuses.
Waited 20-25 minutes.
Placed fuses back in.
Started car without touching anything.
Let car idle for 20 minutes.
Cut swith off/back on until the guage lights turn on (but did not crank)
Switched off ignition imeditally and then back on again.
Allowed switch to be on about 10 seconds with guage lights were lit up, without cranking to allow reset.
Turned car off.
LED did not blink when re-starting car.

.

Drove home on Interstate. Hit about 60mph and CEL came back on. Pulled over while car was still running to check LED.

Same thing: It's a single blink each 3-4 seconds continiously.


I agree that it's not RPM/Speed related. After reading a little more from web/etc., it seams to throw code after temp is over 600 degrees? That would vary from day-to-day and whatever driving condition it would take for the temp to rise in open the sensor?
I see no performance change/issue when the code shows up.
 

ChrisBMacon

New Member
I'll try and capture a video of the LED tonight and attach. I think I need to update my membership to allow attachments or I can email it.

I apprecaite you input. It's driving me nuts!!
 


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