So last year I posted this and received a few helpful responses. I let it sit but now that my Neons transmission died it's now or never. It's still failing for NOx and HC which is weird as NOx is usually indicative of lean burn and HC is indicative of excessive fuel or dirty. The original HC was 1.2992 with .800 being the max and NOx was 1.64 with .800 being the max. Now its looking better but.... Can any mechanics chime in? I'm reading online bad egr, bad IAC, bad catalytic converter. EGR is $300 to replace, iac is $65-$190, catalytic converter is??? It has four new ie four pull n pay fuel injectors and four new AC Delco oem spark plugs. All help appreciated. Should I go the brand new route and order four new injectors? What else ?
1997 Chevy Cavalier still wont pass emissions... What now?
- Thread starter 97prizm
- Start date
Man you're really close to passing on both HC and NOx. And no active codes.
Do you have a scanner to check fuel trims?
Do you have a scanner to check fuel trims?
What state are you in that they actually use a sniffer on a 1997 OBD2 car?
I agree that looking at long term Fuel Trim is next before firing the parts canon.
I agree that looking at long term Fuel Trim is next before firing the parts canon.
Try CRC Guaranteed to Pass, or sell it to someone in a non-emissions county or another state 
You might also get away with E85 or at least E15, if available in your area
You might also get away with E85 or at least E15, if available in your area
Agree about checking fuel trims.
How many miles? Does it burn oil? Lean AND bad rings?
How many miles? Does it burn oil? Lean AND bad rings?
Also a fresh oil change will soak up HCs temporarily. If you can pull the EGR valve off you can clean its passages out with a frayed bike brake cable in a drill. Run the car with the valve off, it'll make noise from the exhaust side and idle fast/ poorly from the vacuum leak. If it doesn't do either your passages are still plugged.
High HC is incomplete burn, and high NOx is typically running lean. Stuck EGR I think could do both no?
Still - we need to see the fuel trims.
At what RPM do they use this sniffer?
California does
I had to deal with a similar series of issues in Georgia back in the day.
You can clean or replace the EGR valve and as one poster already mentioned, use Guaranteed to Pass.
Follow the directions, get the oil changed (that helps too), and you should be fine.
You can clean or replace the EGR valve and as one poster already mentioned, use Guaranteed to Pass.
Follow the directions, get the oil changed (that helps too), and you should be fine.
If he kept a 97 cavalier emissions compliant in California, until now, he’s a miracle worker lol
Looks like Colorado per the inspection sheet.
Delete please. Duplicate info of shortyb's post above.
Yeah, any other state that still does emissions inspection on a 97 would've passed the car if the CEL isn't on and there aren't any codes!
Original cats?
Command the EGR to open, Should make the engine run rough or stall at idle.
EGR pintle position should read zero at idle uncommanded.
If everything is good...Fuel trims etc, A bad catalyst can cause both conditions. Can't depend on early OBD2 to set a P0420!!
EGR pintle position should read zero at idle uncommanded.
If everything is good...Fuel trims etc, A bad catalyst can cause both conditions. Can't depend on early OBD2 to set a P0420!!
Very interesting, subscribed.
It's been many years since I lived in a county that actually measured emissions, but when I did there were exemptions for new cars under 3 years, old cars (~20 I think?) AND depending on the year and type a $ ceiling. ie If you put ~$250 into a $2,500 car they would pass you for 2 years regardless of the test outcome. Pretty decent really, because they knew for the most part people in this situation probably did not have $$$$$ to spend on emissions related repairs. Maybe check that angle?
I'm no mechanic, but have had success reviving a few older vehicles focusing on the PVC system.
+1 for fresh oil change and decarbonize EGR. If you still have the old plugs I would put them back in a run a can of the Seafoam spray foam stuff thru it followed by a good cleaning of the throttle body and MAF (I would NOT use that stuff on brand new plugs, fouled a set that way once).
Reminder, get it good and hot / Italian tune-up before the retest
It's been many years since I lived in a county that actually measured emissions, but when I did there were exemptions for new cars under 3 years, old cars (~20 I think?) AND depending on the year and type a $ ceiling. ie If you put ~$250 into a $2,500 car they would pass you for 2 years regardless of the test outcome. Pretty decent really, because they knew for the most part people in this situation probably did not have $$$$$ to spend on emissions related repairs. Maybe check that angle?
I'm no mechanic, but have had success reviving a few older vehicles focusing on the PVC system.
+1 for fresh oil change and decarbonize EGR. If you still have the old plugs I would put them back in a run a can of the Seafoam spray foam stuff thru it followed by a good cleaning of the throttle body and MAF (I would NOT use that stuff on brand new plugs, fouled a set that way once).
Reminder, get it good and hot / Italian tune-up before the retest
If he had his own sniffer at home I would run a little MMO in the gas and see if the idle smooths, would increase voc but who cares at this point?
Guarantee to pass them fresh oil just works and is a good idea when you are on the edge
I dumped some rubbing alcohol in the gas tank in a 78 Camaro in high school. It improved the sniffer results dramatically, although I can’t remember what, specifically. It’s worth a shot.
If he is in California or a state that follows Ca smog rules(I think there is 11) you gotta pass or scrap the car. Selling it out of state is also an option.
Ca requires cars back to the1976 model year to have tail pipe emissions tested. Then they went further and make you run it on a dyno in hopes of it failing
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