Why no check engine light?

[scotts364]

Just curious why I don't get a check engine light but have something so out of whack it fails the HC 185ppm and NoX 2100 ppm pretty bad.
The only time I have seen the check engine light is under hard acceleration it may blink occasionally.

I hope to get back to troubleshooting it soon, maybe I can find something actually wrong.

A few years ago it failed and I replaced the Engine temp sensor, O2 sensor, spark plugs, ran 2 bottles of smog pass and almost passed. Finally I replaced the cats and it passed but the HC's were still pretty high.

I had a knock sensor #1 code that came back after clearing the ECM but still no CEL.

Anyone know how to properly test the Mass Air Flow sensor? Mine is a Hot Film type, which I believe has a square wave output not a voltage based on resistance.


Scott

[Jeron]

CEL flashing on acceleration sounds very familiar. I would start there. O2 maybe...

[fastfredracing]

A flashing CEL, usually indicates a misfire, I am under the assumption that the light flashes to show urgency in performing service,as continous driving with a misfire, will damage cats, and or possibly cause engine damage

[Jeron]

My recorded misfires have had a solid CEL.

I don't think he meant "flashing" but rather comes on only for a very short time then goes off.