my 90 sunbird (2.0L auto) failed the stupid e-test. HC was good (33ppm, 72 limit), and CO was good (0.02%, 0.4% limit), but it failed on NOx emissions. Over double the limit... 1842ppm (limit is 825ppm).
what do you need to do to lower NOx emissions?
and it failed on the rolling test, not the idle test.
NOx is created with heat. So make sure the car is running at 195 degrees f or so. Also make sure the egr system is working.
My Car
You might also need a new Catalytic convertor.
My Car
has a brand new one, just welded it in a couple weeks ago.
i guess i just dont understand how this thing could fail, because it doesn't really HAVE any emissions system to speak of. one O2 sensor. a cat. that's it. no AIR injection. no EGR. nothing.... so what the hell am i supposed to check?
maybe ill throw an O2 sensor at it.
I would also try a de-carb. Get some carbon buildup out of the combustion chamber.
My Car
Ur car should have a EGR valve.Most 90-95models had that on most makes and models.I would clean the throttle body with some valvoline synpower carb choke /thottle body cleaner.This is specifically for tbi models unlike regular carb cleaner which does not work the same cleaning carbon out.U can buy it at advance auto FOR SURE.After doing that u should change ur plugs,wires would not hurt but,not necess.I would also run one full can of seafoam in ur fuel and let the car run a day or two in ur fuel and locate ur egr valve,I am almost certain ur car being a 90model it should have one.U should clean it with a wire brush and the above and make sure the pintal inside it moves FREELY up and down,if its shot,replace the part.This is a vital part in the emissions and controls unburned fuel b4 it goes to the cat.Hope this is useful and this should clear up the problem.Make sure u drive the car at highway speeds for 15-20 minutes prior to the test a hot engine will not have the unburned fuel emissions blowing thru raising the nox.
-Here is what ur EGR valve will look LIKE and U do have one!!!! All 2.0 and 2.2 vin #P and K have what is know as a Negative back pressure egr.This is used to reduce oxides of nitrogen emission levels caused by the high combustion chamber temps.OK
If you cant figure it out in Canada there is aproduct you can add to your gas that guarantees you will pass if not you get double your money back worth a shot???
Ron Love wrote:-Here is what ur EGR valve will look LIKE and U do have one!!!! All 2.0 and 2.2 vin #P and K have what is know as a Negative back pressure egr.This is used to reduce oxides of nitrogen emission levels caused by the high combustion chamber temps.OK
thx for the pic. are you sure the 2.0L OHC has EGR? according to the Haynes manual I have it doesn't!! i'll take another look when I get home though...
Ron Love wrote:.This is a vital part in the emissions and controls unburned fuel b4 it goes to the cat.Hope this is useful and this should clear up the problem.Make sure u drive the car at highway speeds for 15-20 minutes prior to the test a hot engine will not have the unburned fuel emissions blowing thru raising the nox.
Vital part, Yes.
And NOx is not unburned fuel. HC's (hydrocarbons) is Fuel, CO (carbon Monoxide) is partially burnt gas (doesn't fully make it too CO2), NOx is Oxides of Nitrogen (the oxygen being a variable amount). The leaner you get the more NOx you are going to make. At 2500 F cylinder chamber temp, you start making NOx. So the egr sends already burnt gas into the cylinder. This gas cannot combust (make power) so the cylinder temps go down because the controlled explosion is not as great (without egr)
And yes make sure you heat up your cat before smogging. By putting a load on the engine for a couple minutes. Catsrun more efficient while hot.
My Car
im so glad we dont have this crap in ohio
Tony Wise(emokidpsy) wrote:im so glad we dont have this crap in ohio
bastard.
well you were right, it DOES have EGR. although my haynes manual says it doesn't, so it has no information about it.
does anyone have some sort of diagram or something that shows how its routed?? it's all buried in there and id rather not rip the whole car apart trying to figure out what the problem could be.
Too check and see if it works. Get a vacuum pump, and pump away (bout 5 inches hg)
and see if the car feels like it wants to die. Like stutter and stumble at idle.
My Car
In the Haynes Book #38015 Page 6-2 Diagram 1.1b Item 8 (82 thru 94 Models.)
It is pictured in the engine bay
Hope this helps
Alont
If its the original part,I would replace it.Typically when a egr vavle's pintal is sticking the car tends to choke,but sometimes the car will run but not up to par.I would go thru the act of congress to replace it and remove the carbon where it mounts and install a new one.Napa carries them for sure advance and auto zone may not stock this as a normal item.Prices vary for this but guessing about 20bux at least maybe more.
Yes, you have an EGR valve. high NOX emissions comes from higher than normal CAT temperatures though, not just cylinder temperatures. If you are running pig rich with a brand new cat, it could do the same things as the egr valve being stuck closed. Your cat will die fast if that is the case and since you had to replace it recently, that might be the problem. Did you replace it because you failed on HCs first with normal NOX levels?
Cardomain|
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i replaced the cat cause the car never had one when i bought it.
ill try a new egr valve and see where i get....
I'm with everyone to decarb the sucker too. If the EGR doesn't work by itself, definitely decarb with GM top engine cleaner and run some SeaFoam through the next tank of gas. Might help. Let us know how it resolves.
See if anything here will help:
http://www.j-body.org/forums/read.php?f=47&i=29727&t=29390#29727
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well guys, looks like im in trouble.
it failed initially for NOx. i figured out that it was running hot cause the t-stat wasn't opening all the way. so i replaced that, threw some new plugs in, ran some of that 'guaranteed to pass' stuff.
i took it in again, NOx is well under the limit now. but this time it flunked CO and HC during the idle test badly. mechanic said its blow-by, was probably being masked by the excessive temps before.
Just a GOOD idea u should change ur oil and filter.U probably ask why?Bc with ur engine running rich the excessive fuel vapors or trash as I call it stay in the oil and will raise ur hc levels an co.This is not some bologne any true mechanic would recommend it if u have a excessive rich issue,just remove ur oil fill cap if u smell fuel odor and ur oil of course its contaminated ur oil ,So a oil change is in order.This may not ultimately solve the problem but,trust me it HELPS ALOT.Ur car will not emit nearly the high levels of hc and co and if I think of anything else,I will post it.OK
