Just failed my smog test on the partially rebuilt, 2.8L motor with a few things done that could affect emissions (i.e new rings, oil stem seals, timing chain, distributor, 1.6 rockers, ported & polished heads and intakes, ignition coil, spark plugs & wires). Timing was confirmed by the shop as 'set properly' and they reported 'the car runs great.' They recommended a new Cat ($950 installed). Here are the numbers from the test, which showed failures from Low CO2 and High O2, HC, CO, and NOx.
From this Five-Gas analysis chart on the Walker website, this seems to agree with the 'properly functioning engine with a bad Cat' scenario. From searches it seems high NOx on its own results from over-temperature ignition (>2300F), from a host of different causes, but that when HC, CO, and NOx are all high, the Cat is most likely bad. As far as I can tell by looking the Cat is original. The engine has about 100 miles on it from the rebuild (cam and lifters 95,000 miles) and is sitting at 1/4 tank, which seems quite thirsty. I'm assuming new rings and main/rod bearings contribute to poor mileage.
So, if you guys concur with the 'bad cat' diagnosis, I'll order the Fiero Store CA-compliant Cat and Head pipe, stainless steel, that I can install myself without welding. Because the OBD1 smog test costs $80, pass or fail, I don't want to return several times.
Thanks in advance, for your careful thoughts and recommendations
Id say bad cat unless your car was overheating. I have been able to pass when close to NO depending on how warm of a day it was but you are way over. I was able to get a walker cat on prime for like 300 bucks and welded it in.
Did Fieros even have "California" cats? I'm thinking not. If they don't check for a CARB approved cat, you should be able to just buy one. (Rodney sells them too, with pipe added to help facilitate installation.)
The NOx is a bit troubling. That's usually caused by a bad EGR. (Does your engine ping at all?) It may help to run premium when you get it retested. Or dump in a gallon of Naptha to about a half a tank.
[This message has been edited by Raydar (edited 04-19-2022).]
oh yeah they will check especially if its sparkling and new. Also if he goes to the same place and pass they will check and be especially rude because he did not let them do the repair. I have actually heard of places failing saying its the wrong carbs number for the car and trying to get the person to do the work at their shop. This is why i take my cars to test only shops.
Edit: also I have seen premium shave off about 200 NO points.. I forget it brings some other level up tho I wanna say HC. I would say you are too far over for that to work.
[This message has been edited by skywurz (edited 04-19-2022).]
Did Fieros even have "California" cats? I'm thinking not. If they don't check for a CARB approved cat, you should be able to just buy one. (Rodney sells them too, with pipe added to help facilitate installation.)
The NOx is a bit troubling. That's usually caused by a bad EGR. (Does your engine ping at all?) It may help to run premium when you get it retested. Or dump in a gallon of Naptha to about a half a tank.
My federal emissions cat installed in 2005 passed California enhanced smog testing in 2014 just fine.
My federal emissions cat installed in 2005 passed California enhanced smog testing in 2014 just fine.
CATs pre January 1, 2009 do not require CARBS stamp. Im still using my Federal pre 2009 CAT on one of my Fieros. They still get the inspection mirror and try to look at it.
quote
Originally posted by IMSA GT:
Smog compliant California cats have to have an EO number on them. This usually starts with a "D".
At least use a Fiero cat
[This message has been edited by skywurz (edited 04-20-2022).]
Great feedback, thanks all! I shall confirm the EGR is OK with the vacuum test (at present it idles well and doesn't ping), fill up with premium gas, get an appointment early in the morning (cool weather is better than hot, I read somewhere), and go with TFS set up. I don't have facilities to do welding. I had never heard about the use of mirrors before!
Back when my Fiero was in California I also had trouble getting it to pass. I replaced just about every applicable part: plugs, wires, cap & rotor, egr. Injectors and FPR were also new. I don't typically love just throwing parts at a car hoping they'll work, but the car had been sitting untouched in the desert for 12 years so replacing the old parts didn't seem like a terrible idea. What I ended up having to do was a new cat. A latino joint on Anaheim in Long Beach put a new one in for $450 parts and install and then it passed with flying colors. He didn't have an exact match on the shelf so the one he put on was actually a bit bigger than the stock cat.
[This message has been edited by statue4 (edited 04-20-2022).]
I'm having "failed emission" nightmares just reading through this thread. Been there and done that with most of what was said on here.
First advice is that if you know your cat is old (and it's an aftermarket one) it would be probably a good bet it needs replacement. If you do replace it, the smog tech will indeed check the OE number stamped on the body of the cat to make sure it is compatible/certified for your particular car. (i.e California CARB approved) Also, if buying a new cat, PLEASE keep the paperwork in your glovebox. The smog tech will need it and appreciate that. Or........he will be checking under your car with a "pancake" mirror.
2nd advice is (as was discussed above) for high nox you might want to check your egr system. (especially the EGR valve and that someone put in the correct orifice washer hole size)
3rd advice....get the engine running as good as you can and don't forget to check the little things that might affect engine running.driveability. (i.e. pcv valve condition, throttle body cleaning, sensors that affect engine running like water temp, TPS, IAC, etc.)
3rd advice....get the engine running as good as you can and don't forget to check the little things that might affect engine running.driveability. (i.e. pcv valve condition, throttle body cleaning, sensors that affect engine running like water temp, TPS, IAC, etc.)
Yes, engine/coolant temperature is crucial for a smog test, and I don't think anyone's mentioned the thermostat. If there's not a fully functional 195°F one installed, replace it!
[This message has been edited by Patrick (edited 04-21-2022).]
Yes, engine/coolant temperature is crucial for a smog test, and I don't think anyone's mentioned the thermostat. If there's not a fully functional 195°F one installed, replace it!
Kits & Patrick, I will check my thermostat and fan switch. I'm pretty sure I have Rodney's 180 degree thermostat but I can't remember if I changed the fan switch. Hopefully there are part numbers on these so I can tell.
Patrick, I will also look into getting some $ for my old cat, which I wouldn't have thought of. I was just going to take it to the municipal recycling center.
That seems like an outrageous price for a cat, installed or otherwise. I realize you're in California, but still.
