ISFFUN

iTrader: (4)

Short explanation - car is from out of state after moving back to CA. Registration is expired now and the more time goes by the less chance I have of not getting impounded for expired tags. Attempted to get it to pass smog and failed twice, going for third test tomorrow. Here's what I'm worried about: getting flagged as a gross polluter, then having to go in front of a state smog referee after 2 fails, according to this link here.

Before I go any further - I've read about every single forum post in the world (forums like yotatech, smogtips, supra forums, CL etc) in the last 36 hours about people in this situation, watched YT videos about the readings, the EGR blah blah. I've read many posts here, including my own about a different car several years ago with a similar issue-unfortunately I don't remember what the fix was.

I do have the 1997 FSM and I'm very mechanically inclined, having removed the engine twice, the head twice, the transmission etc.

Here's what I've done:

-Replaced head with lower mileage 1995 Supra NA head
-Replaced front cat with Magnaflow SC300 direct fit CA spec (haven't done test since new cat was in - but old cat was caved in and the honeycomb was mostly crumbled and deteriorated)
-Cleaned out EGR valve and checked entire EGR system, including new modulator. VSV is functioning, and vacuum to EGR port makes car run like crap.
-TPS replaced P/N 89452-22090: 3,000 miles ago, 5 months
-Spark plugs Denso (3134) PK16R11 : 3,000 miles ago, 5 months old
-ECT sensor P/N 89422-20010 : 4.000 miles ago, 5 months old
-Replaced both upstream O2 sensors with Denso 234-4209 - 4,000 miles ago, 6 months

Most recent smog test results:



15mph : %CO2 = 13.8, %O2 = 0.6, HC = 37, CO% = 0.04, NOx = 866 (fail NOX)
25mph: %CO2 = 14.0, %O2 = 0.3, HC = 30, CO% = 0.03, NOx = 634 (pass)

One tech tells me too lean
Another tech tells me too rich

Does anyone know TECHNICALLY how to read those values?

Blkexcoupe

iTrader: (8)

High NOx is usually caused by being too lean and not enough fuel. It's usually caused by the O2 sensors going bad or a bad cat. I think you should pass with the new cat. If not, I think you can appeal to the BAR saying you spent more than $450 trying to repair the car, and they'll give you a 1 time pass on smog. Just make sure you take the car on a spirited drive and really warm up the cat before taking it in to go smog.

ISFFUN

iTrader: (4)

OK, as of yesterday/today I changed the front cat (Magnaflow 444748 CA "direct fit" - not quite, the rear flange WAS MOUNTED AT THE WRONG ANGLE) put in a new Toyota OEM PCV valve. Passed test with lower NO and CO%. The old cat was gutted all through the center if I didn't mention that already, there were chunks of it inside the midpipe before the 2nd cat.

However, HC at 15mph is near the limit at 42 of 49.

If that means it's lean, then the only think I can think of is poor injector flow and I know the rubber gaskets are a little worn on those from when I pulled the head.

ISFFUN

iTrader: (4)

From what I gather, you can only use that $450 number if you paid for the work at a certified smog center, not if you DIY. Not 100% sure though.

Blkexcoupe

iTrader: (8)

Congrats on passing! That is amazing how much the CO and NOx went down from the new cat.

As far as your HC numbers go, I would try running a different fuel in your car and get a new gas cap. I failed smog earlier this year (due to the gas cap), but I was really close to failing on HC, and the smog tech told me to try running a better fuel. I filled up with chevron fuel before the test and took it for a 30 minute drive flooring it as much as i safely could. This was the results of the test:

The test I failed for a bad gas cap


A week later with a new gas cap and a tank of chevron gas.


That is a good point. I'm not sure if they'll take DIY work, but you can prove you paid for the parts. I had a friend who worked at a shop write up his own receipts and submitted them as proof he was trying to fix the car.

KahnBB6

iTrader: (5)

Congratulations on passing, ISFFUN!! Very happy to hear you are able to keep that 1/120 on the road.

Your last resort lines up with what I encountered a few months ago trying to pass smog with my '93 Cali 5-speed. For me this was also just after I had moved back to CA with what I thought was a problem-free, clean running car.

I replaced everything (injectors, O2 sensors, plugs/wires/cap/rotor, distributor, TPS sensor, IAC-V, ECU coolant temp sensor, EGR valve, EGR VSV, EGR modulator, entire top Y-manifold/plenum, cleaned all EGR passages of carbon buildup, rebuilt/repaired correct type ECU, catalytic converter #1 and catalytic converter #2) except the cylinder head. I was chasing a Code 71 (EGR obstruction/malfunction) as well.

Some of those parts genuinely failed but in the end (for me) once the usual suspects had been covered it came down to replacing the #1 catalytic convertor with a new OEM unit. I'd replaced the #2 catalytic convertor with a Catco "direct fit" model because I figured the first OEM having only been replaced a few years earlier was in good shape. Not so in my case. Replacing the #1 cat finally did the trick.

Like you I have also found that the "direct fit" catalytic convertors available for our cars generally don't fit without some cutting, realigning and welding new angles for the pipes. I have kept my old dead cat assemblies stored away for the next time I need a cat because I have been told by a Catco (Airtek) representative who deals with the manufacture of the assemblies at their factory that many of these SC300 specific units are now special made to order only in their new part numbers and thus it's a good idea to send them a bad cat assembly you know actually bolts into the car directly for them to use as a fabrication template.

...Either that or many only one of us needs to do that and they'll take that as their new in-house design they'll keep in their shop

ISFFUN

iTrader: (4)

Thanks for all input everyone, hope this helps someone in the future.