Everything was fine except for the NO ppm read 840, which is over the 500 limit. does anybody know if my spark plugs could cause the NO ppm to read so high? i just changed them and the motor seems to be idling a lot better. Since the motor swap last spring I haven't changed the plugs at all. I've only driven it a few times this winter.



I want to share something with you - the three sentences that will get you through life. Number one, 'cover for me', Number two, 'oh, good idea, boss', Number three, 'it was like that when I got here.'

Where did your Ecotec come from - did it have and EGR on it? If it was from a Saturn L-series that had the EGR setup, there could be differences with valve timing (I'm guessing a bit here) that could influence your results.
NO is produced from high combustion temperatures - which can occur if your knock sensor isn't working properly, allowing for too much advance. Engines with EGR dilute the mixture with exhaust gases to lower the peak flame temperature. I believe that our cars also came with 3 way catalytic converters, that SHOULD help to reduce NO. I put one onto a '87 Century a few years ago which never originally came with one, and the numbers went from over 500 to 36.
I don't believe that your plugs should have any influence over your readings. They can affect HC and CO if misfiring, but not likely NO by itself.
If the guy testing it really lugs the motor by running it in too low a gear (like 4th under load at 40km/h), it may add to the problem. What was the RPM recorded on the test? Sometimes getting someone else to run the test can "fix" your "problem". This is only under the assumption that you have a 5 speed - I forget what it said in your profile.
I'm not sure who I would recommend in Niagara Falls - I've only used a couple of places in St. Catharines, one in Thorold, and one in Burlington near where I work.

John S wrote:Where did your Ecotec come from - did it have and EGR on it? If it was from a Saturn L-series that had the EGR setup, there could be differences with valve timing (I'm guessing a bit here) that could influence your results.
NO is produced from high combustion temperatures - which can occur if your knock sensor isn't working properly, allowing for too much advance. Engines with EGR dilute the mixture with exhaust gases to lower the peak flame temperature. I believe that our cars also came with 3 way catalytic converters, that SHOULD help to reduce NO. I put one onto a '87 Century a few years ago which never originally came with one, and the numbers went from over 500 to 36.
I don't believe that your plugs should have any influence over your readings. They can affect HC and CO if misfiring, but not likely NO by itself.
If the guy testing it really lugs the motor by running it in too low a gear (like 4th under load at 40km/h), it may add to the problem. What was the RPM recorded on the test? Sometimes getting someone else to run the test can "fix" your "problem". This is only under the assumption that you have a 5 speed - I forget what it said in your profile.
I'm not sure who I would recommend in Niagara Falls - I've only used a couple of places in St. Catharines, one in Thorold, and one in Burlington near where I work.

motor is from an 04 cavy. the rpm reading says 2861rpm. im going to have a mechanic look at it, im pretty sure my cat is toast.



I want to share something with you - the three sentences that will get you through life. Number one, 'cover for me', Number two, 'oh, good idea, boss', Number three, 'it was like that when I got here.'

the mechanic is saying its bc I don't have an egr valve. do the ecos even have one? i want to try some "guaranteed etest pass" liquid. ive heard of it working for people.



I want to share something with you - the three sentences that will get you through life. Number one, 'cover for me', Number two, 'oh, good idea, boss', Number three, 'it was like that when I got here.'

yea eco's dont have egr and would not have to be installed to pass a 1040 emission test. they have to pass for sure without egr or they would of never hade the engine in production, definitely is probably another problem maybe your cat, bad fuel injectors? take it to a good technician and let them look at it, if your running lean it will produce high nox, could be a # of things, and the people that usually work at the emission places dont know how to work on cars or they would be fixing them too. They basically have a picture photo of your engine bay and emission devices and check mark that they are there and hook up a scan tool make sure they work and read a gas anylzer and thats it. so dont take there word for it

The Ecos used in Cavaliers never had an EGR that I've ever seen - I know for sure that my brother's '02 does not.
If it's not a stock 3-way cat, then that's likely where your problem lies. Usually if the mixture's off, it will throw off the other readings too, but not always.
The Ecos used in the Saturn L-series (at least early ones) DID have EGR - that's why I questioned the engine's origin in my previous post. Yours probably won't even have a place to install one.
That "guaranteed to pass" stuff is just a concentrated cleaner - and the guarantee doesn't apply if there are any mechanical defects in the car. In other words, as long as there's nothing wrong, then they guarantee it will pass. Gee, what a concept...
I know of guys running high percentages of methyl hydrate to get their cars to pass, but that's typically to fix high HC levels. I'm not sure what effect that would have on NO, but either way, it's certainly not good for your fuel system.
By the RPM, I would guess that they ran the test in second gear. So much for any "lugging" theory...
I have a friend working at a shop here in St. Catharines that may like a challenge such as this. Let me know if you want more info, and I can see what I can do. I trusted him to R&R the cylinder head on my car last year - and he did a nice job with that, so this shouldn't be too much of a challenge hopefully. I don't usually like ANYONE else to work on my cars, so you know that I think he's trustworthy.

we had the same problem on my girlfriends car (accent) last year. everything else passed with flying colours.

you need to bring the combustion chamber temps down. thats one of the functions an EGR valve does. this is what we did to help...

- changed coolant

- new thermostat

- higher octane fuel for one week before test (ran 91)

- run test on higher octane fuel

- fuel injector cleaner

- new air filter (needed one anyways)


changing the coolant and t-stat just helped the heat from the block escape faster. to my knowledge the coolant had never been changed on her car anyways. the higher octane fuel, while the car is not fully tuned for it helped to bring the combustion chamber temps down. the fuel injector cleaner was for the hell of it, which is about all that guaranteed to pass stuff is.

we also had a friend run the car for us on the etest dyno at his shop. we brought it in warm like your always told to and it failed. let it sit for a half an hour to an hour and ran it cold and it passed with flying colours. so my advice is to do the above if you can and run it cold when you do the test, wich will also help with the combustion temps.



1997 Cavalier Z24 - 16.3 in 1320 and falling...

thanks im gonna put new coolant in the car, higher octane and im going to go with a colder plug. im going to put some fuel injector fluid in too.



I want to share something with you - the three sentences that will get you through life. Number one, 'cover for me', Number two, 'oh, good idea, boss', Number three, 'it was like that when I got here.'