the magnaflow cats I have only last about 2 years then need to be replaced, but I think the turbo has a lot to do with that. the ones that fail alot are the ceramic cat's, try looking for the "metallic" cat's and do some reading online, apparently they tend to destruct less but not sure if they smog as good, worth a read though if you are looking into cats in the future. I just horribly failed my E test as well, and it seems both my cats bit the dust again. The stock cats though dont seem to fail or go bad very often, not sure what you are running.

when nox goes down and HC goes up, usually means a little unburnt fuel or a misfire, so checking the timing was a good idea but I would leave it around 9-10 degrees on an n/a. retarding it past a certain point will raise the Hc again. changing the cat might do it in your case.

 

Thanks, Ali! This two year aftermarket cat lifespan seems to be pretty consistent in many circles. I didn't expect it so much with a non-turbo but so far it seems to be the same.

My car is running an OEM front cat (brand new in 2010 and replacing the then 18 year old factory original) and a Catco "Direct Fit" secondary cat which is the more likely failure culprit. I've just ordered the same model as before from Catco (#66266 model, soon to be superseded by #93266). I'd only ever consider spending on an OEM second cat on the TT swap.

I'll do some reading into metallic vs ceramic. I'm not sure what material this Catco uses but I chose it because it's Cali legal and mostly preserves the factory exhaust routing (still requires some cutting and reshaping and an O2 sensor bung relocation). I want to be able to bolt in Supra TT factory exhaust parts and cats in the future.

It really comes down to whatever cats have been certified with those all-important little Executive Order numbers stamped on them :/

I've been told recently that Walker universal cats are better now but a couple of years ago someone echoed your preference for Magnaflow universal cats.

I readjusted my timing to 10 TDC after my test yesterday. I've renewed my registration already and even if a new tag isn't issued until I have a smog test I think I'm okay to drive on my existing tag until I actually cross the first of next month. That being the case, maybe there is time to send the Reman ECU in to Tanin and get it back.

There was one and only one instance of cylinder misfire just before my mechanic and I ran the test. This was with the Tanin repaired '92 ECU. I shut it off and restarted and it was perfect again. A quick drive around the block was flawles with no misfires. I reasoned that I had adjusted the idle set screw about 200-300 RPM too low and brought it back up again. The ECU may have not been able to keep up with the incorrect setting. Never happened again with either ECU.

In all, the car passed every other test other than HC's. I think it was just the aftermarket second cat being worn out since I had that installed in early May 2014-- that's consistently two years.

 

I only mention it because it is sort of odd to get High HC and low CO due to just the cat being bad.
I think bad cats would show both numbers being high and sometimes higher nox but its a bit of a fuzzy science to be honest.
Like on mine when I see High HC and High CO I generally know that running rich has killed the cats again, but then again my wideband often is pegged in the 10-11 range on pulls so I sort of expect that every few years (which is why I am moving to metallic cats now vs ceramic, pretty much only for non california aftermarket options).

Also if you have a stock main cat, thats the one that does majority of the work I would think that one is still good on an n/a unless you were pouring gas down it at some point with one of the bad ecu's. the stock main cat has so much cat material in it they take a really long time to go bad on a non turbo car.
I would still be wary of a lean misfire, especially since you just overhauled the egr system.

check out this page
http://www.crypton.co.za/Tto%20know/...emissions.html
the egr is operated by a vsv and the vac lines that run to the throttle body. those vac lines off the throttle body are ported, meaning they get vacuum at only certain throttle positions.
So basically you want to make sure you do not crack the throttle body open too much, or else you will be giving those ports vacuum earlier throwing the system off... does that make sense?
The charcoal canister is similar it is the third ported line off the throttle body.

A safe bet would be to close the throttle plate as much as possible and reset the ecu and let it learn, stock car should idle at 650 or you are doing it wrong.
Those 2-300 rpm's you raised it might have given some of those ports vacuum, maybe a long shot but I have played around with so many throttle bodies I have become intimate with their inner workings.

this is for a different toyota but you get the basic idea from it

 

Yesterday I had a new Catco #66266 rear catalytic convertor installed (actually just had the old cat section cut out and had the replaced the brand new one welded in and kept my old piping, since the fit still is off with those).

Last week I put the 1992 ECU back in since it ran much better and I sent the Reman ECU out to Tanin for repair.

Today I got a new pre-test with the brand new second cat and... the numbers didn't really change much in terms of HC's. CO and NOx were lower.

HC's at 15 MPH were about 161 PPM on average (previously 179 PPM) and HC's at 25 MPH were around 54-67 (previously more or less the same)

For reference, Maximums are 82 PPM @ 15 MPH and 48 PPM @ 25 MPH.

Idle tailpipe HC's were up into the 650 range at one point before we really heated up the cat. Once heated up it dropped to about 33-36 at idle. The new #2 convertor might have had only 12 miles on it at the time of this test. And I did heat it up on the highway before pulling it into the dyno bay although there was some cooldown time of 20-30 minutes between when I arrived and when the car was pulled onto the rollers.

The car was otherwise running just fine at this point.

...

Then something happened that shouldn't have and I didn't stop it from happening in time. My mechanic tried cleaning my Karman-Vortex MAF sensor. Now I did remove it just to *inspect* it visually or wipe anything off of it with a dry clean rag or disposable shop towel... but he went ahead and cleaned it.

It wasn't even with "MAF cleaner" solution but it was enough to destroy the sensor. Before I could stop him it was done. Even though shop compressed air was used to get it completely dry... as you'd expect, the engine runs horribly now, over-fueling like crazy and won't maintain idle for a half second before stalling out.

So now it's parked and won't be started again until a new KV sensor is in there.

I feel like such an idiot for not having stopped the cleaning in time but what's done is done.

Some awesome people here helped me find a couple of used replacement sensors (thank you Bflatsharp and jimmymac!) but I'm car-less until they get delivered early next week.

Additionally, even though a probe test of the exhaust before both cats is in order I've just gone ahead and bought a new OEM #1 catalytic convertor. I reason that you are right, Ali: all the overfueling and bad misfiring over the last few months and the brief use of the 1995 ECU probably did foul up at least the front cat with unburned fuel.

Also, Ali, you mentioned that the first cat does the most work so this would eliminate that potential culprit too.

That's where things are at again, waiting on more parts.

....

Ali, I did readjust the throttle cable a third time in the last week to fine tune the idle. When all of this is back together I can go back and reset the TPS setting again but I followed the TSRM directions and looked at the sensor readings in OHMS for each operating range on my multimeter to get them within spec (and an ECU reset was done right after). Maybe I should do it again since the throttle cable was physically adjusted?

On my car the correct TPS adjustment (physically) seemed to be all the way in one direction within that little bit of range you have to work with.

...

And I did read that document but I am still having trouble understanding: with a perfectly serviced and clean EGR system I may have caused a lean-run condition? I'm not sure how that can be dialed back... if it is the case.

I've read... but I don't fully understand how that correlates... or is correctable.

I'd post some pictures in this post but the picture upload function on mobile doesn't seem to be working right now.

 

Yes, the more open the throttle body is, the faster egr will come on or may even be on at idle when it shouldn't be. basically you back out the idle screw all the way so that the throttle body is in its most closed position. then be sure to check the tps is still in range or even re-adjust that.

long shot maybe but if you cracked the throttle body open enough before it could mess with the egr and emissions stuff, so closing it up all the way is the easiest way to eliminate those issues..

 

Ali, I was all set to try out your suggestion tonight but... today the car passed smog with flying colors!

The new front OEM cat came in from UPS and shortly after I had my shop install it. After putting only fourteen miles on it we ran another manual smog dyno test (measures the tailpipe numbers only). I didn't pay attention to the other numbers because at that point it was reading 0 HC's at 15mph and 25mph! We double checked the probe and tried it a second time. Same result. There were low CO and NOx readings but all FAR below their limits.

Even though the Tanin repaired Toyota Reman computer comes in tomorrow I just went ahead and had it smogged at a STAR Test-Only station anyway. By the time I got there a couple of miles later the HC results had settled to at or below average numbers.

This says to me two things:

1.) All the overfueling and rich running conditions that has plagued the car for the last few months (and possibly before I actually noticed symptoms) probably led to a gradual fouling of a fairly new primary OEM catalytic convertor. It lasted six years from brand new in 2010.

2.) There may or may not be programming differences between a 1992 SC300 M/T Cali-Spec ECU and a 93-94 SC300 M/T Cali-Spec ECU... but so long as it's been serviced you CAN pass smog with one of the 1992 ECU's on a 1993 or 1994 Cali-Spec chassis.





I can't fully express what a sigh of relief it was to pass the test, finally. Unfortunately my registration tags on the plates are definitely expired now so driving around is going to be dubious at best. In a plastic carrying case I'm keeping copies of all my receipts for registration renewal, smog test results, smog test receipts and all the major receipts for the repairs I've made on the emission system in the last few months. That will ride in the car for the time being.

I did pay the DMV registration fee before the deadline but the renewal was labeled "incomplete" due to my not having been able to take the smog test until now, one day before the tags are invalid. Anyway, here's hoping the ARB and DMV push that through and get me a new set of papers and tags pronto

There is supposed to be a Cali vehicle code statute that allows me to drive the car until my new papers and tags have arrived.

I'm going to call the troubles this thread was made for solved at this point. TRULY solved. It's something of a Pyrrhic victory for me but it's done. And the car feels great now. No complaints.

....

I need to immediately take the car to a Toyota dealer or driveline shop to have the rear diff pinion seal replaced and the fluid flushed with new Redline Heavy Shockproof since the leak I noticed before has gotten a little bit worse. That should not be a big deal to fix even with the delicate torque needed on the companion flange.

Then one of the hoses going into the Heater Control Valve needs to be replaced since it's old and has a very small but persistent intermittent leak.

Then I'll double check to see if anything in the exhaust piping needs a new seal with all the work that's been done. I have the parts for all of those jobs on standby.

What a relief!

 

Congrats on clearing that major hurdle!

 

Thank you!

 

Oh, and a word of advice to anyone who wants to get a smog "Pre-Test" done.

Don't. At least, don't fully complete the test. Be sure to have it aborted BEFORE every part is completed. And only get a "Pre-Test" done to test all the other emission control systems not directly related to the tailpipe numbers.

For tailpipe numbers, get a "Manual Test" done.

Why? Well, because even though a "Pre-Test" isn't supposed to actually count against you or even show up on your ARB Test History record... it does. While you think you are running a mock version of an official test, the Pass, Fail or Abort result goes on the vehicle's permanent record anyway. One can only assume that result gets counted for or against your car just the same as an official test.

At least with an "Abort" result the there is no indication of how well the car did. Better, a "Manual" test doesn't actually record anything at all. You also don't get a printout of all the results and you'll need to take a camera phone picture of the monitor in real time but that's not difficult to do at all.

I said I had no complaints up above but I'll amend that just a bit. Working hard to preserve your car's clean smog record and wishing to privately take a practice test to see if it will pass or not should not be viewable by the state to use against you (and anyone else who owns the same model as you) despite your efforts, time, money and energy invested to troubleshoot issues.

I guess I did not fully understand this reality because my recent supposedly "off the record" and/or "private" mock-smog-tests that I paid for to make sure the car was going to pass the ACTUAL test are viewable on my car's permanent record in the ARB database. That is not generally reflective of what people are led to believe they are getting when they have a "Smog Pre-Test" performed.

You can check your own car's record (California cars only) here:

https://www.bar.ca.gov/pubwebquery/v...pubtstqry.aspx

That absolutely reflects bias when it comes to older vehicles. The OFFICIAL results should be the only thing the ARB is looking at no matter how well or how poorly your car does. They do not see it that way.

To anyone reviewing this thread to educate themselves, make sure any Pre-Tests you give your car are aborted partway through... or just get a Manual Test on the dyno if you need to verify your SC's HC, CO and NOx tailpipe readings are within the state allowed limits.

 

Thanks for all the awesome and very helpful info, Kahn! I seriously need to pass smog ASAP! As my neighbor just informed me that, yet another, ticket has been left on my vehicle dispite paying all fees prior to the due date. Unfortunately, I usually have to pay the $10 processing fee per ticket anyway. Which adds up when you park on the street and the meter maid people know where you live, often leaving multiple tickets on the same day for the same violation of expired registration! Grrrrr!! That should be illegal!! I currently have 6 tickets. :-/

 

Glad to help, Meghan! I detailed this thread in hopes that maybe it can be useful for anyone else in the same situation.

Yikes! I have been paranoid about the stories I've read about Parking Enforcement ticketing indiscriminately for expired tags and your story confirms my worst fears I have garage parking so I can avoid that at home but I have been very, very careful not to park anywhere other than private lots recently. I am in the same exact situation you are with the registration being paid but the tags being in limbo-- even after having passed smog.

I agree that such a practice should be 100% illegal. They do this because it's a source of revenue pure and simple. As far as I can tell, all states do this. It's just that in California the smog testing requirement for renewal makes it that much easier to take advantage of people.

It's not right but the only thing we can do other than passing smog is to register a car Non-Operational. And of course that's both a waste of money and zero help if it's your only car and you need it for work and really anything that keeps your life going.

Also the new tags won't come in right away a couple of days after you've passed the test either. My "Incomplete Registration" document says to allow 30 days for the renewed tags to arrive. Ridiculous. I am going to attempt braving the DMV line on Tuesday morning on the chance I can get a 30-day temporary permit. It might be $40-$50 by itself and I have no idea if they'll even do it since I paid by renewal fees online.

It's kind of hard to keep your driving to a minimum and stay out of public parking areas when you get a call for work. And of course they know this.

Stay focused on the troubleshooting and keep asking questions and trying each successive part in the system, Meghan. You'll get it passed and this will be over :/

 

I highly suggest going to the dmv in person. Two years ago I had paid registration but had not yet passed smog. When I finally did pass I waited and waited for my tags to arrive because the smog printout indicated I needed to do nothing else. But my tags were never sent. I got 3 parking tickets that go around for expired registration. Eventually, I had to go to the dmv to prove that I had indeed passed smog and only then were new tags issued.
A similar instance last year when I changed insurance carriers and the dmv requested proof of insurance. You would think that companies providing coverage and assisting in the California low cost auto insurance program, of all companies, would be submitting all necessary documentation and proof of insurance for their policy holders to the dmv. Right?! Nope!! Had to go take care of that myself too.
The crappy thing is that due to the DMV's failure on their part to process my registration in a timely manner, in both instances, caused me to get denied financial assistance from BAR for the CAP program to get my car to pass smog this year because in 2014 and 2015 I had a lapse in registration of more than 120 days.
Not my fault.
It sucks!
So definitely go brave the long lines at the dmv. It's probably worth it.

 

Meghan, thank you for that. It's all I needed to hear to brave the DMV today and get an answer. It turns out that you cannot get a temporary permit unless you've failed smog or had your car impounded.

The wait this time was not long at all. Amazing. I was able to get the DMV clerk to confirm for me that my registration was valid in the system and that Sacramento would be sending out my new tags and registration papers tomorrow. He was only able to give me a certified receipt proving that I've paid for my registration and that it's valid. It still doesn't allow me to park on the street though.

I was told 1-2 weeks extra before my tags might come in. If it's the full two weeks that would bring the total wait time up to 21 days. Hopefully less.

Your situation the last time making you ineligible for the CAP program this time is just rotten. No, none of that makes sense if the objective were to actually help someone :/

 

You may be right about the DMV not giving you a temporary registration card if you haven't failed smog and if you're within the 30 days. However, I can vouch that if you have failed smog and you are past the 30 days (like myself) they will provide you with a free temporary registration card once you pass smog and assuming all fees were paid for in a timely manner. Which is what they did for me yesterday when I went to the DMV. I provided proof that I had finally passed smog, ( took 4 tests but I finally passed. Barely) and since Sacramento hadn't processed the smog certification that was sent electronically they had no problem providing me with the temporary while I waited for the new tags to be sent. They said that if I had come In a couple days later Sacramento probably would have processed it by then and that they would have provided me with the new tags/stickers right then and there. Luckily I was fine with it either way. They were even kind enough to sign off on my five parking tickets for expired registration. And just in time too. The entire visit took about two hours although online it claimed that the wait was only 30 minutes when I checked online. So I guess it was worth it.
Now I'm still dealing with the repercussions of trying to pass California smog because prior to the work being done to attempt at getting my car to pass, my car was running great. Now, unfortunately, my car has been running poorly and left me stranded last night. Thanks California!

 

Meghan,

I am so glad you were able to pass and get the legal weight off your shoulders!

But now that you've had your mystery snap return and had the car strand you... not so good :/