Failed emissions test

Forgive me... my two main cars are diesels so I haven't had a car checked for emissions since 2006 and I don't think PA was doing dyno testing back then.

The '88 325is I recently bought failed the dyno emissions test in PA.

NOX at 10,500 (3600 PPM limit) and CO at 350 (260 PPM limit).

Sonic and I aren't sure why. The cat is new. O2 sensor is relatively new. Car seems to run fine.

Any ideas?

the saturn failed because it needed new plugs and an air filter.

NOx is typically caused by lean burning or high combustion chamber temps, CO is typically incomplete combustion. so...vac leak and worn plugs/wires/cap/rotor maybe?

Ian F wrote: NOX at 10,500 (3600 PPM limit) and CO at 350 (260 PPM limit). Sonic and I aren't sure why. The cat is new. O2 sensor is relatively new. Car seems to run fine.

With those numbers, it sure doesn't seem like it.

What was the HCs?

to strizzo- you can have both high NOx and CO with normal combustion, especially if the O2 sensor is sort of working (switching), and the catalyst is not.

Anyway, you should check your records for at least the catalyst- normally, NOx and CO work together, so a working cat would bias the emissions one way (rich for high CO) or the other (lean for NOx).

Oh, and your numbers don't make sense- unless they are using some odd measurements, the CO should be 10k/3k, and the NOx should be 350/260 ppm.

Especially for the "standard"- for a state sniffer, it would make sense that the allowed CO would be ~10k the allowed NOx. For sure, it's that way for the federal standards/measurements.

Eric

ANY exhaust leak before the catalyst will skyrocket the NOx. I bought my latest track car for cheap because they couldn't get it to pass on NOx. It was running at 1800ppm and the limit was 700ppm. A comprehensive fuel injection service and EGR port cleaning got it to 1000ppm. Then closer inspection found a 1" gap in the weld at the catalyst intake side. Two minutes with the mig sealed it and the NOx went down to 150ppm. Sad part was that this cat was put on by the previous owner to pass emmissions. If it was installed correctly it would have passed with flying colors. Luckily they screwed up and I got a 240sx for $700

The one and only time my 1990 Miata failed emissions I had the O2 sensor unplugged with no Check Engine light. If you recently messed with it, maybe double-check your connections.

Was the car fully warmed up before you got the test done? We had high failure rate with cold or luke warm cars here in MA when we dynoed cars. Thankfully we got rid of that usesless testing now.

44

In reply to 44Dwarf:

Hmm... I was wondering about the "warm" bit. I was doing all three cars that day (only this one got sniffed, as mentioned) and the BMW went from my house to the dyno station which is about 1.5 miles away...

Cat is new. O2 sensor is new. As are plugs, wires, cap & rotor (all replaced by Sonic). I had to loosen/drop the header pipe to replace the shifter bushings, so maybe I didn't get it completely re-seated to the manifolds. So I'll re-check those this week, as well as the sensor connector and the numbers on the test report.

Thanks for the suggestions!

My folks live in Pa. They live in a rural area tho, so no emissions tests required....yet.

I'm sort of split on this issue. I live in Tn. and the state doesn't require emissions tests...or even an inspection, but it is required in the 4 major cities in Tn.

I think making an emission inspection dependent on your zip code is unfair.

whatever you find or not i'd take it for a little romp before inspection to get the cat nice and toasty.

integraguy wrote: My folks live in Pa. They live in a rural area tho, so no emissions tests required....yet. I'm sort of split on this issue. I live in Tn. and the state doesn't require emissions tests...or even an inspection, but it is required in the 4 major cities in Tn. I think making an emission inspection dependent on your zip code is unfair.

it's about fixing non-attainment areas. That's why ispections in Pittsburg, PA are more important than in, say, Ligoneer, PA. It's one way that can be seen as trying to fix a localized emissions problem.

I realize that in a state with "zip code" based emissions requirements, it's about "fixing" certain areas. But why should someone who lives 5 miles from me....and often uses the same roads, be allowed to "skip" the burden of the inspection?

My parents rarely drive more than 100 miles from their home anymore....so they are never in Phila. or Pitts. But my "neighbors" who live JUST outside the city limits of Memphis, don't have to have a vehicle inspection. I don't know about Pa. but at the very least these inspections should include ALL vehicles within 50-100 miles of metro areas.....or no vehicles at all.

Hey, I said I'm conflicted about this issue.

integraguy wrote: but at the very least these inspections should include ALL vehicles within 50-100 miles of metro areas.....or no vehicles at all.

You've gotta draw the line somewhere... and no matter where you draw it, somebody on the wrong side gets screwed... so splitting it up via zip code is as good as any other system.

Also, in the areas where emissions isn't tested, the car is still supposed to pass a visual component check, so that doesn't give you carte blanche to gut the emissions systems.

Any state that requires emssion tests or inspections fail in my book.

I would clean the EGR system and test that it is functioning.

Check that the oil is fairly new and clean

check and replace if dirty the air filter

toss a bottle of rubbing alcohol in the gas tank

Down here they do it by County. Helps a little on the pissiness factor.

We also no longer use the dyno test.

Gearheadotaku wrote: Any state that requires emssion tests or inspections fail in my book.

what you gotta understand is it's nothing more than a money grab

here in NC emission testing is done county by county on '96 and newer cars and all counties do "safety" inspection.. I put it in quotes because the only things they check are the headlights, tail lights, brake lights, horn, and wiper.... nothing about whether the brakes actually work, no steering check, and for sure no shock check... oh by the way you fail if you have after market window tinting that's even as dark as a pair of cheap sunglasses... but it can be as so dark as to be blacked out if it came from the factory that way

The 4 areas in Tn. that require emissions tests DON'T bother looking for all the required "hardware".

When I bought my current Civic, I had to run it through the emissions test before I could apply for a plate. It passed with flying colors. Then, a few months later, when an exhaust leak developed, I took my car to my favorite muffler shop. Imagine my surprise when they pointed out that my car had no catalytic(?) converter. Apparently, the previous owner had removed it. It still had passed the emissions test AND there was no MIL light on.

These state mandated emissions tests are a crock. Thankfully we did away with them in Kentucky. I distinctly remember waiting in line while a guy in a new Cadillac had to subject himself to these stupid tests when his car was brand new! Did I mention his car was brand new? Just an absolute tax on society.

I do recall passing with flying colors when I owned my 79 ford pickup truck. The same truck, two years later failed miserably at a different testing garage... not because of emissions, they wouldn't even test it because it did not have a cat. There was some arguement (probably started by me) that the truck did not originally have one but I don't recall the details or if that was accurate. All I knew was it didn't have a cat on it when I bought it and it still passed. When I explained that even without the cat it still passed, I was ignored.

Another reason for the failure? The gas tank neck was modified so that the larger, leaded nozzles could fit back in the day. When I explained that since leaded gas is no longer sold at gas stations and therefore this was a non-issue, I just got another long arguement.

Then I went back to the original testing garage that passed it two years earlier. The lady on duty refused to come out of her office and other workers refused to do anything either. You would think they would stagger their lunches, you know for the sake of the taxpayers. After knocking several times, she unlocked the door, came out, didn't say a word, taped a handwritten sign on the door that said "At lunch, come back later" and then proceeded to lock the door and continue doing nothing.

At that point I had enough. Our testing was by birthday, if you were born in an even year, you were tested that year and the test was good for two years. I went ahead and promptly sold the truck to my wife for $1, since she was born a year ahead of me, she didn't have to have it tested until her birthday, the following year. When her birthday came, she was nice enough to sell it back to me for, you guessed it, $1. We did this for a few years until the state wised up and pulled the plug.

I recently had my own problems with an emissions test on my recently rebuilt Supercoupe. In my case a new tune on the computer dropped HCs by 75% and CO by over 90%.

I know smog tests can be a pain, but a trip to Mexico was enough to show me what a country with no real emissions laws at all was like...the pollution was disgusting. I'd be fine with a system that says so long as a car passes, it doesn't matter what's been done to it. That, plus a visual check to make sure the car has cats, is pretty much what the TN test is like. The California standard with its visual test is absurd, though. In CA your car can fail if the engine looks modified even if it passes the sniffer.

Anyway....

I remembered the test report this morning.

CO: 0.10% (Pass), HC: 0144ppm (Fail), NO 4197ppm (Fail)

The previous numbers I quoted were the raw tailpipe readings.

CO % x liters: 0.25 reading with a 1.1 limit

HC ppm x liters: 360 reading with a 275 limit

NO ppm x liters: 10492 reading with a 3600 limit.

Test performed at1950 RPM with 12.64 dilution (??) at ASM 5015 loaded.

The car has no air injection or EGR systems and passed visual and functional inspection of other emissions control systems.

I also consider emissions standards and testing to be a necessary evil in densly populated areas. All one has to do is go to a classic car show and then hang around the lot at the end when all of the cars are leaving to truely appreciate what modern regulations and systems have done for overall air quality. Hell, I'd advocate testing for motorcycles since it doesn't seem any Harley owner can tune a carb to save his life. If you've ever had to follow a pack of them down a rural road, then you'd know what I mean...

Ok, those numbers make a heck of a lot more sense.

Based on those numbers, I suspect you are running lean, and not an exhaust leak- the exhaust leak would bring down the HC and CO but not the NOx. OTOH, running a little lean will really reduce CO, but there can be a lot of HC's left, and your NOx is way out to lunch.

See if you can put a volt meter on your O2 sensor- just to make sure it's doing something- more than likely, it's going to be hovering around .1-.2 v, and if it's 0 or something above .3, someting is very wrong with that.

But for a car that age, I would bet you have a small intake leak somewhere, and it's out of the range of authority that the O2 sensor can adjust.

To find a leak, you can use a propane torch (not burning), with a small flow, and just move it around the soft spots- the engine note will change a little when you find the leak.

(being that I live on emission development, bring e'm on.)

Eric

Thanks Eric. I'm hoping I'll be able to take a look at it in the next couple of days (I'm currently elbow-deep in searching for an oil leak in the g/f's 1800ES).

Gearheadotaku wrote: Any state that requires emssion tests or inspections fail in my book.

dam, missed this post.

you obviously don't live in an area that has people who don't care about their car. I wish they would add safety inspections besides emission testing here. It pisses me off to no end that people are allowed to drive unsafe and barely drivable vehicles with no problem.

Just a quick note about the relevant work that has been done based on Eric's new diagnosis:
In the last 4 or so years, I've replaced the intake elbow, throttle body gasket, intake manifold gaskets, IACV and it's hose, valve cover breather, oil cap, and all engine gaskets except for the mains.

Ian, the first place I would look would be the throttle body. There are several fittings on it, and one of them may have worked loose. That TB is one I pulled from a junkyard and wasn't in perfect condition, but when I got the car back in 2003 it had an eta intake manifold and throttle body on it, which really choked it down at high RPM...it had eta fuel injectors too, it was quite odd. Once I swapped the relevant i parts back on, it ran so much better, and was one of the first things I did