Just came back from smogcheck and it was passed barely. HC(PPM) max allowed 61 passed w/60, NO(PPM) max allowed 493 passed w/490. Don't know what these numbers mean -anyone cares to explain?. The tech left a note to check egr value/passage. Also, could O2 sensor has any contributions to this?

This is what I found. Could someone confirm whether this is normal on a 95 EGR Passage? I've seen a few videos on yt and can't find anything like it. I thought there should be caps to drill and hammered out.

note: egr valve and the opening as shown here were cleaned couple years ago with carburetor cleaner but didn't know anything about the passage until now.
Thanks

 

you can delete egr and still pass smog

so have you done any basic maintenance for ignition parts? cleaned injectors, iacv, adjusted valves, changed fuel and air filters etc?

pass is a pass so you dont really have problem

 

interesting, then why the tech made a note on the certificate that egr passage is blocked and needs cleaning.

that is the thing couple of years ago it was also almost failed, the tech then suggested it needs all the tune ups you mentioned and more or risk failing it the next time around which was yesterday.

I certainly accepted the challenge and took the whole intake manifold apart and cleaned everything couple of years ago. On top of that; replaced with new air filter, fuel filter, thermostat, coolant pump, distributor cap, rotor, spark plug wires, spark plugs you name it. And a new oil change before show up at the smog-check shop. also fuel injectors were cleaned with ultrasonic cleaner and tested.

As you can see, the numbers are either worsen or the same as couple of years ago -don't have the old certificate to compare it to. Everything I did, didn't gain any reduction on the numbers obviously.

HC(PPM) max allowed is 61 by the state regulations and mine passed with 60.I don't know what else to try because I'm not confident with the next smogcheck and 2years is not a long time.
NO(PPM) max allowed 493 passed w/490. common, it right on edge.

Anyways, are those ports supposed to be welded like so on the 4th gen?

 

Of course they are not supposed to be melted but since you can pass it doesn't really matter. Someone wanted to get rid of egr so blocking was done. And those technicians many times recommend to change parts that they could sell em and not always theyre necessary

New cat and/or o2 sensor might be ok if they have never been changed

Atleast with my car the cat needs to be really warm to get good smog numbers out of the engine but I have aftermarket exhaust system and egr deleted

 

Good to know.

Here in the states smog tech are not allowed to do anything else in their garage except smog-check. Pretty specialized.

UPDATE: i'm not making this up, as I was working on the car earlier today and took those pictures above. I forgot to set the alarm at the end of the day and now the car is stolen. Just an hour ago I heard my car started up and I quickly looked out my window and saw it took off. Police just came by to make a report. Likely not going to see it again. This happened, and I don't know how to react. This suck.

 

Ouch - looks like then its time for beer!

 

2 on me!

UPDATE2: this is unreal, good news bad news. good news is that just got the car back!. the bad is that other people are not so lucky. So he dropped off my car 40miles away then picked up 2 other cars there. 2 new victims called the police to report it b/c their alarms went off, the officers showed up then realized they just found my car. I wish I could tell you this is a joke but it is not, what a crazy night.

 

This is incorrect. He will fail visual for a deleted EGR.

OP you would have to take off the intake manifold and clean the EGR passages from both sides.

Other than that, do a basic maintenance, plugs, o2 sensor, and make sure your ignition timing is correct, reset the ECU, run the car about a full tank of gas before going back to the smog station so the ECU is ready.

If you've passed don't worry about it.

High NO usually means you're running lean, high HC usually means it's too much gas in the cylinders...Google will explain it better than me.

 

I could back this up, they do have a list of visual and measured inspections

In my case, where do you recommend drilling? both left and right side in addition to the top holes?

true, not so sure about next time. want to get it done now and cheaply.

how cant it be lean and too much gas at the same time? I thought too much fuel is rich. timing belt/tdc are set and also used light gun to double check. The only 3 other options are egr and sensor and cat converter which will brake a bank. I think I'm going to do the cleaning on the egr passages for now if there is nothing else is recommended. Since the shop do offer free retest, I'll use that free out of jail card for o2 sensor.

would unplug the battery consider as a reset?

 

If the manifold is off, you can access the egr passes so they can be cleaned. The excess passages won't be cleaned but you'll clean it up enough to keep it working well.

That's why I say Google symptoms of excessive NO and HC and it'll get you farther than I can.

​​​​​​Unplug battery would work.

 

its 100% correct since there is no visual everywhere

 

If they list EGR on the smog sheet under 'visual' then he will fail. He's already said they check for it.

 

Those welds are factory, just FYI. 5th gen manifolds had the plugs.

 

About 20 years ago I was failing for nox on a 95 civic. The emission station circled egr as a culprit. The 95 dx didn’t have a egr. The catalytic converter was the problem.

 

Thanks everyone for their inputs.

cool, i was thinking the last brain dead owner did.

would the intake manifold from 5th gen goes onto 4th gen, i could pull one from the junkyard and avoid the drilling?

hope this is not my case, that's a big chunk.


based on what i've gathered. (do correct me)
high NO reading means combustion is too hot - needs EGR to to cool down - probably due to passages got blocked
high HC reading means again ECU is trying to cool down by injecting more fuel - resulted in incomplete combustion (running rich)

---or---

high NO reading - bad Cat as @stint1 pointed out and/or blocked EGR passages
high HC reading - bad o2 sensor resulted in ECU fails air/fuel ratio (i'll try back probing)

ok any chance the high readings on NO and HC is due to leakage somewhere through out the exhaust manifold to catalytic converter which is why o2 sensor is having a wrong reading?

 

Do you have any CEL codes?

 

no. (note: tech would reject to do the test if cel if present)