Went in today to get my inspection. 1990 Honda Civic DX MANUAL. Everything passed except 4 tests in the Emissions area:

:::::High Speed (25 mph):::::
Standard / Current Reading
HC (ppm) 197 / 236
Nox (ppm) 1440 / 4622

:::::Low Speed (15 mph):::::
HC (ppm) 203 / 233
Nox (ppm) 1577 / 3489

I can't call my self an enthusiast nor even a beginner when it comes to cars, so you can understand that I have no idea where to go from here / what to check. So that's why I come to ask you guys.

Last year all the car needed was a timing belt adjustment and it passed the 2nd test no problem. Year later, things seemed to have changed.

Background information:
I do have an engine light that comes on (and also came on before my last year's inspection), but it appears that it only comes on when I'm driving the car for a while and go to a certain rpm's before switching gears (usually 4th or 5th gear). After I turn the car off, the engine light goes off, and when I start it up again, the light won't appear until I go to high rpm's. We haven't, for whatever reason, actually gone in to check what the light means, but I don't know that we can when it always turns off after turning the car off?

Also, about 4 - 5 months ago we had to replace the engine starter because it went bad. (if that counts for anything)

We also recently discovered that there was oil in the spark plug chambers, but I've been told that that doesn't mean anything bad or cause any actual problems (because the oil was located on the outside part?)

So, I don't really know what else to tell you, I just don't know where to begin, and if you could lead me into the right area, like you guys did last time <3!!! I'd really appreciate it. :]

 

Some possibilities include:

-Bad catalytic converter
-Bad O2 sensor
-ignition timing out of spec
-Bad temperature sensor or thermostat

Start by retrieving the CEL code(s):

 

Thank you for such a quick reply.
Well, I turned the car on, and it is indeed blinking, but I'm having trouble indicating what exaclty the problem is. The light blinks continuously with a 2 second pause in between each blink, but according to that manual page you gave me, I don't see what that is indicating. ????

SHOULD I run the car until the engine light turns on (by means of driving it around) then check the light? Or is this telling us what the problem is?

 

Could be code 1. Do you have a catalytic converter?

 

From my understanding, if it's 1 constant flash, that means code one, 2 flashes and a pause, then 2 flashes, that indicates code two (and so on), right?

And yes, I do have a catalytic converter (I thought all cars did). However, I was talking to my uncle and we don't know that it has ever been replaced before. I'll have to go through papers and see if it ever had that done. But my uncle and I are also thinking that if it is Code 1, being Oxygen Content, that could likely mean that the Oxygen Senor is bad and we might need to replace it. But I don't understand how a sensor going bad would make emissions worse???

So, where do we go from here?

 

Based on your description, I think you have CEL code 1. if you are unsure, post a video of the LED blinking pattern.

The O2 sensor in conjunction with the ECU (computer) determine the optimal air/fuel ratio to burn in the engine cylinders. Therefore, if the O2 sensor is bad, the engine could run rich, consistent with the high HC emissions data you posted.

Given your NOx emission was extremely high, the catalytic converter (CAT) also may be bad. Running very rich for even a relatively short period of time can lead to rapid destruction of the CAT.

 

So with that being said, which should I go for first? the CAT or the O2 sensor? :O

I guess O2? cause it's far less expensive?

 

You really should troubleshoot both:

 

Always being over on both HC and NOx really suggests a bad cat converter. Generally if the only problem is a bad O2 sensor you get high HC and CO but NOx is OK. But if you get the O2 sensor code consistently you'll need a new sensor regardless.

Also like Ron pointed out, the engine must warm up to normal operating temperature, or the ECU will not control emissions properly.

 

double check the EGR system