JDM 92 GT-Four RC Colorado Emissions, Catalytic Converter

92RC

Member
So here's the other things I've done to improve emissions, I made this video (I was slightly annoyed at the time, I felt better when I was done because I got to learn about the car) to show what needs to be done.

https://www.youtube.com/watch?v=4P2XZCGeTDY

The next day I did remove the strut tower bar, there were some things attached to it (boost controller part, coolant reservoir for chargecooler) so I figured it was easier to prop it up.



It was seriously in the way so I determined it was easier to take it out, this is how one of the previous owners attached those to the bar, interesting...



Ah much better



Here is the broken throttle body coupler, I was told this allowing air in will cause the engine to run lean




VS the new one, here's where I bought it https://gt4-play.co.uk/shop/throttle-bo ... er-coupler



The hose seems pretty standard but the metal part seems pretty well made and machined, not perfect and pretty utilitarian but in theory the hose could be replaced if needed


Old turbo to intercooler hose, I feel this was clamped too far in causing the hose to curl up on the edges over time creating a boost leak.



It was kinda dirty inside so I wiped off a good amount, it's my understanding this isn't a cause for alarm but I'm still quite new to working on turbo cars so I'm not 100% sure






A bit cleaner


The bump on this wasn't as dramatic by the time I buttoned everything up, I was concerned it wasn't forming a good seal at the time but I ended up breaking one of my clamps (good thing they came in a 2-pack) so I tried again shortly after taking this picture.


If anyone has a brand/product recommendation on non crap clamps let me know, I got these at O'Riley's and I don't remember if they had more expensive ones or not.



So I had to take the strut tower bar off to get at the throttle body connector, because this isn't expected on the stock version this part of the clamp is touching the bar. What's weird is this part appears to have a right way up and wrong way up. The clamp adjustment seemed to me to be upside down so I moved it and tried again, there isn't much I can do about it other than find a similar "low profile" clamp if such a thing exists.



At least the turbo hose seems to be on there nice and tight and forming a good seal




Day 3, adding the strut tower bar back in (the service manual calls it a "Suspension Upper Brace"), I had to borrow a smaller torque wrench for the middle firewall bolts (there's what's a "Tool Library" where I live so I bought a year subscription of that) which required 21 NM (which seems surprisingly low to me, my other wrench doesn't go lower than 40 NM.





I drove the car around (this was before putting the new oxygen sensor in) and I was able to notice a lot of improvement. The idle was much more consistent and the power delivery was much smoother so I must have installed the throttle body coupler on correctly which is nice (I was constantly humming The Fray's "Over My Head" when working on this because I felt I didn't know what I was doing, I guess I wasn't in over my head). No noticeable boost leaks as well (the loss of power was obvious when I had boost leaks). If you compare the turbo hose from when I freshly installed it vs when I put in the oxygen sensor its pretty bulged in the middle which indicates to me air was sealed tightly and heated the hose up to deform it without breaking the seal. Most other stock-ish RC models I've seen pictures of online have the hose bulging in the middle like that.

So yeah, I think that's it! Once the weather gets nicer for a bit I'll get my emissions test repairs scheduled and hope I pass!
 
Good to see you got things squared away and working properly again. Good job.

Regarding your intake air tubes/hoses, remember, your ST185 has an air flow meter (AFM), which is what tells the ECU what the rate of air flow is going into the intake manifold. This is what tells the ECU what fuel amount (injector duration) is required for the engine at every moment. If you have any slight leak from the discharge of the AFM to the inlet of the throttle body, you will have an error in the actual air flow amount versus the measured air flow amount, which will cause a non-ideal air:fuel ratio.

Also, if you ran your engine for a while rich (which is possible if all the measured air going through the AFM isn't getting to the intake manifold, due to after-turbo booster pressure leaks), your cat could be partially covered in soot, causing the continue exhaust odor you may be noticing after the repair. This should correct itself after a good long drive if the air:fuel ratio is good - the heat of the cat should burn that soot off.

Way to go ...... good job!
 

92RC

Member
Thanks everyone! I'm glad I'm on the right track! I'm waiting on a couple of unrelated parts to come in before I can drive it but I should be able to drive her soon. I almost got a ticket for having an expired temp tag (I was pulled over by a State Trooper, it's my understanding the local police don't care about expired temp tags) so I'll have to get that renewed...again...before doing my drives. The trooper that pulled me over gave me his card so in theory I can be like "y'all already got me" but it's only $7 to renew so I might as well do that just in case.
 

alltracman78

Active member
Nice!

Good job replacing that TB connector. That was a problem waiting to happen. How much larger was the silicone hose than the intercooler output?
FYI the ST165 TB coupler works for the RC also. If they're still in production. Also you can get an MR2 TB adapter (very similar to the aluminum piece you have) in the states. I think ATS racing makes them? Or did?

What brand is that strut tower brace? Pretty cool it has the mounting points for stuff on it. I've never seen that before.

Next time I would suggest a 5SFE (5th gen) O2 sensor. The pin in the wiring should be the correct size. And once again a US part that's cheaper and easier to find. That looks more like something from 80s Toyota wiring. That way you won't have to mess with the pin like that. Also, I hope you saved the original O2 connector. That way you can reuse it again.

If you have to cut something, cut the sensor. You never want to cut the harness if you can help it because it's irreplaceable (or close enough to). The sensor is much cheaper/easier to replace. I know you didn't cut the harness, just saying FYI. :)
 

92RC

Member
alltracman78":2nr2641d said:
How much larger was the silicone hose than the intercooler output?

It wasn't super loose if memory serves me correctly, pretty snug before I put the clamp on but it seemed like it wasn't going to form a good seal without the clamp. When I got the car it didn't have a clamp over the stock coupler (and it was already cracked) but looking online it looks like most other engine bays of RC models (both stock looking and somewhat modified) appear to have one, here's the most stock I can find https://youtu.be/sPCHwlQS5V0?t=75

FYI the ST165 TB coupler works for the RC also. If they're still in production. Also you can get an MR2 TB adapter (very similar to the aluminum piece you have) in the states. I think ATS racing makes them? Or did?

Good call on that, it's the same part on both the ST165 and the ST185 RC but it's discontinued by Toyota. I didn't bother to look up the ST205 part but it's not the same part number at least. I'd be interested to document any alternative OE quality couplers if anyone ever needs one but I'm not seeing anything other than what I bought https://www.nengun.com/oem/toyota/17861-88381

The ATS Racing MR2 Throttle Body Coupler is all metal, probably the same back plate but it's too long for the RC, even if I could chop that extra length off I doubt that would ever work.
http://www.atsracing.net/Parts/Details/E-ATS-TBI

Same with the GT4-Play for the non RC ST185
https://gt4-play.co.uk/shop/throttle-body-intake-pipe

What brand is that strut tower brace? Pretty cool it has the mounting points for stuff on it. I've never seen that before.

The car came with a Marché sticker on the side (Edit: And invoices from 2016ish them that I've roughly translated) and I guess that's the JSpeed company http://cs-marche.com (you can see a lot of their current parts say JSpeed on them) but I'm not seeing anything online for purchasing that part new.

That bracket is glued to that bar (with epoxy maybe?) but looking at RC engine bays I think the stock brace has a bracket built in? It looks like the charge cooler overflow tank is mounted in the same spot on most of the RC models including the YouTube link above, again I have a part of the boost controller mounted to that spot as well.

Next time I would suggest a 5SFE (5th gen) O2 sensor. The pin in the wiring should be the correct size. And once again a US part that's cheaper and easier to find. That looks more like something from 80s Toyota wiring. That way you won't have to mess with the pin like that. Also, I hope you saved the original O2 connector. That way you can reuse it again.

Wow I'm dumb, well the plus side is I saved $20 making that monstrosity and now I know I can get the exact fit if I ever encounter problems.

https://shop.advanceautoparts.com/p/den ... gen+Sensor

If you have to cut something, cut the sensor. You never want to cut the harness if you can help it because it's irreplaceable (or close enough to). The sensor is much cheaper/easier to replace. I know you didn't cut the harness, just saying FYI. :)

I may be an idiot but I'm not stupid :p I have to figure out how to repair one of the wires in the charge cooler level sensor harness so in that instance I might cut it and replace it with a generic plug but I'm not sure, if I can find that plug used on other similar Toyota models I could scour salvage yards for one.
 

alltracman78

Active member
92RC":2x7zlaka said:
It wasn't super loose if memory serves me correctly, pretty snug before I put the clamp on but it seemed like it wasn't going to form a good seal without the clamp. When I got the car it didn't have a clamp over the stock coupler (and it was already cracked) but looking online it looks like most other engine bays of RC models (both stock looking and somewhat modified) appear to have one, here's the most stock I can find https://youtu.be/sPCHwlQS5V0?t=75
Yeah, RC came with a clamp too.
Any hose should be a snug fit to start, without any clamp. If not it's too loose IMO. The clamp just ensures it stays on and holds under pressure.



92RC":2x7zlaka said:
Good call on that, it's the same part on both the ST165 and the ST185 RC but it's discontinued by Toyota. I didn't bother to look up the ST205 part but it's not the same part number at least.
ST205 is too large. On both ends. Larger TB (60mm vs 50mm? ) and larger IC outlet.


92RC":2x7zlaka said:
The ATS Racing MR2 Throttle Body Coupler is all metal, probably the same back plate but it's too long for the RC, even if I could chop that extra length off I doubt that would ever work.
It works if you cut it down. That's what I did. Many years ago. :p Nothing wrong with what you have, just didn't know if it was easier to get the ATS parts.

92RC":2x7zlaka said:
The car came with a Marché sticker on the side and I guess that's the JSpeed company http://cs-marche.com/ (you can see a lot of their current parts say JSpeed on them) but I'm not seeing anything online for purchasing that part new.

That bracket is glued to that bar (with epoxy maybe?) but looking at RC engine bays I think the stock brace has a bracket built in? It looks like the charge cooler overflow tank is mounted in the same spot on most of the RC models including the YouTube link above, again I have a part of the boost controller mounted to that spot as well.
Interesting.
All 185s have the same strut brace I believe. The bracket for the homologation overflow tank is used for the cruise control in the rest of the cars. Maybe why the RC didn't come with cruise? So that bracket probably was made that way, to accommodate the cruise control, and just happened to work out for the homologation ones as well. :shrug:

92RC":2x7zlaka said:
Wow I'm dumb, well the plus side is I saved $20 making that monstrosity and now I know I can get the exact fit if I ever encounter problems.

I may be an idiot but I'm not stupid :p I have to figure out how to repair one of the wires in the charge cooler level sensor harness so in that instance I might cut it and replace it with a generic plug but I'm not sure, if I can find that plug used on other similar Toyota models I could scour salvage yards for one.

Not knowing doesn't make you dumb. Or an idiot. :)

Toyota has a part number listing of all their connectors. In older cars it's in a separate manual. In newer cars it's in each wiring manual.
Even if you can't find the correct connector you should be able to find another 2 plug connector that uses the same size pins (most of their sensors from that period use the same size male and female pins as the O2) and order a male and female connector so it looks factory.
You can even find a lot of the connectors aftermarket.

https://www.bmotorsports.com/

They have a lot of connectors, pins, and wiring stuff. They even have the tool to help you remove the pins from the connectors.

https://www.bmotorsports.com/shop/produ ... cts_id/366

This one


*Toyota wiring manual. Has all the connector and wiring pin part numbers.
The downside to the Toyota stuff is it's usually more expensive and you can't order just the wiring pins, they always come with a length of wire attached. I personally prefer just the pins, so I can crimp it directly to the wire.

https://www.toyota-tech.eu/wire_harness_rm/RM06H0E.pdf

*
 

92RC

Member
Wow, this is a lot of great information, thanks! I'll have to check out the BMotorSports link because a lot of the plugs on that project alone have seen better days so it might be an idea to replace a handful of them while I'm at it.

When I had set my sights on the RC I thought to myself "Nah I don't need cruise control, it's a sports car!" Fast forward to halfway through Utah on my first drive back from the Port I was like "yeah...cruise control would be pretty nice right about now." I did a longer drive 4 months later and that ended up being fine (probably because I wore more comfortable shoes) but it was a funny lesson in luxuries I often take for granted. That being said I'm not a huge fan of Toyota cruise control systems overall but sometimes something is better than nothing.
 

92RC

Member
Alright, the moment we've all been waiting for, the conclusion to this particular Celica saga!

First off, thank you everyone very much for all of your helpful comments and discussion, I really think this was a team effort and I couldn't have done it without all of you! I'll definitely be reading forums first for weirder fixes, most cars mechanics work on these days are newer and can be "plugged into" to do a large chunk of the diagnosis, I'm sure some have experience with older more simple cars so I feel anything in this time period pre-1996 exists in a weird middle area that requires very specific knowledge.

Anyone not feeling like reading another essay I'll give you the TL;DR, the oxygen sensor did it!

Anyway, rewinding to January, I took a 200 or so mile journey in the mountains and I have to say, she drove great!
Looking at my fuel economy I'm not seeing any major improvements yet but...it is a sports car...that I accelerate fast in and whatnot...so as long as my fuel economy doesn't get any worse I should be good.




The only video I made was something for a friend of mine, I had been sending him videos using this song for the past week and I decided to make 1 more. https://giant.gfycat.com/CaringUnfinish ... cicada.mp4


So I got home and ended up throwing the Celica a 30th birthday party, this was when I noticed the kinda stinky exhaust smell went away and the car just smelled like a normal car when it was running so that was a major plus. I ended up scheduling an appointment with a shop listed in the "so ya failed an emissions test huh?" pamphlet Air Care Colorado gave me, just to double check my work. They assured me over the phone they specialize in emissions work and they would be happy to look at my car. I mentioned on the phone "Just to clarify, this car is is pre-OBD2 and you won't be able to just scan it" "Shouldn't be a problem!" Well just in case I did some "light reading" and prepared a detailed guide (complete with those little bookmark post-it thingees) of what was already done to address the emissions work including the printouts of the testing the oxygen sensor, I really just wanted them to hook it up to some sort of emissions machine before I take back to get another $25 emissions test, I figure if there was anything else wrong with it they could find it and I would be in even better shape then before.





Well they called me several hours after I dropped it off and they were like "So...we can't plug it in, we won't be able to determine anything with the emissions stuff." The woman that called me was really apologetic and explained she was relatively new at being a service writer and despite my warnings she didn't realize there weren't cars that couldn't just be plugged into. I told her "well now you know, any car pre-1996 you can't plug into" and she was like "see I didn't know that either!" They're nice folks, I hope I can do business with them in the future, their shop seemed nice and well organized. This has been par for the course on me doing anything on this car so I wasn't super upset. At that point I really really really really knew, if I want anything done I have to do it myself.

So I just said "#&@$ it, I'll just put some octane booster into the car and take it to get an emissions test!" So by golly that's what I did, I think everyone I asked about if I should use octane booster for the emissions test avoided my question so I figured it would retard the ignition timing just a bit if I didn't. The day I did the test I added the booster (I was only running 91 octane for my last 3 or so fill-ups) and topped up on gas and that right there was the most responsive the car has ever felt to me. I had a good feeling about the test. I took the long way to get there just to get some of the "mixed" gas in the fuel lines.

I went to a busier testing facility but thankfully I didn't hold the show up too much. I got in the line that said "all time all wheel drive" and they told me to go to "lane 8" and I was like "Uh..this is all wheel drive" "Lane 8!" "Yes'r thanks!" Yeah that one was an all wheel drive lane too. I noticed this as I got in the waiting area (or as I'll call it, the penalty box), they moved the rollers to the exact correct position before they drove my Celica onto them, the paperwork I had to get at a "secret Colorado department of revenue facility" has the wheelbase on it which tells me there's some database somewhere that has the wheelbase of every all-time All-Wheel Drive vehicle and that's one of the reasons why one can't get an emissions test for imported cars (some of the paperwork I have says "gray market" but same concept) before jumping through a bunch of hoops.

What was interesting was I noticed at least at this location that had signs (well, printed off pieces of paper) forbidding video recording without "written permission" or something like that so I just took pictures this time. I observed the techs never looked at my speedometer and only looked at the little screen from my last video when doing the test. There's a graph showing how they're to accelerate and arrows would appear on the left or right of screen (in green or red) to likely indicate "slow down a bit" and "speed up a bit" so they don't have to rely on the car's speedometer. Good because my speedometer isn't fixed yet (perhaps a spoiler on an upcoming forum post, coming soon!). I'd be interested to learn how the techs drive stick shift cars in these tests, the first time they tested the Celica's emissions there wasn't a functioning tachometer so perhaps it's just based on the tech's individual feel of a car? Not sure, I think you can even see some of their shifts aren't the smoothest (again, from the previous video I posted) but I mean, I don't even shift smoothly from 1st to 2nd consistently in the Celica so that's not a breakthrough observation.



So anyway, I passed! I was concerned because the test was about the same length as the last 2 tests and I figured that was them double checking because the numbers were bad but I guess that's just how long the test takes. Shoutout to sefiroxx and 93celicaconv for pointing out when the oxygen sensor was bad the NOx would be super low while everything else would be high. I'm glad the catalytic converter wild goose chase is now put to an end.



The weird thing about this is the limits are different from the first 2 tests I took, HC was a maximum of 1.5 but on my test it was 1.2, same with the NOx, the test that I passed the limit was 3.0 but the previous ones the limit was 3.5. Interestingly they also listed "Catalytic Converter presence: N/A" and "Oxygen Sensor presence: N/A" (air injection systems aren't very common, I think they only were on 70s cars). I'm assuming the cat and the O2 sensor being n/a is just a mistake made by the tech but I'm reading they have "tightened" the standards for 2022. This is weird to me because I was told "you'll be tested for cars manufactured between this range of years" but I guess they can change those standards whenever they feel like? I'm happy I passed but I would have been really frustrated if I didn't, maybe the EPA back in the 80s and 90s required new cars to pass stricter emissions requirements than what Air Care requires now?

So anyway, I went to the DMV and requested some plates and they just came in the other day. I'm finally like...100% road legal for my Imported JDM Celica!





Yes you read that correctly, because I've reduced this car's carbon emissions, I've declared myself Carbon Neutral! Yeah...that's totally not how that works but I figured I would make a charitable (but tax deductible) donation and pay the extra license plate fee all for a joke (that frankly might only amuse me) but the plus side is I find this plate quite visually appealing so I think it's worth it.

Also, last but not least, if there's gonna be a "Rebel Scum" Celica on this forum, there might as well be a "TK421"



I have a short list of projects I would like to post about but I figured I would tackle 1 at a time ranking from highest priority to lowest so stay tuned! Thanks again!
 

simple

Member
Congrats!

Yeah the CO emissions rules changed this year. Not just randomly, other car forums have been discussing for months.

Beautiful car BTW hope to see it around town sometime
 

underscore

Well-known member
Well I was rooting for you but now... now I'm not so sure...

Jokes aside, congrats on getting it sorted.
 

Roreri

Active member
Great job and congrats! I'm bringing mine out to Colorado this summer and I'll face the test myself. Mine is not running rich or stinky so it sounds like if I add some octane booster I have a good chance of passing.

Colorado has had a history of difficulties with smog along the front range. It just gets trapped there, so they really started clamping down on it in the 80s. I remember clearly that you could not much see downtown Denver from Littleton.
 

simple

Member
It's gross in Denver area. I work in the 35th floor and the haze of yellow is there any day it isn't windy or raining/snow

On the ground level you think it is a clear sky which leads people to believe all these clean air standards are silly.

All cities suffer from it but it is worse in certain ones. Denver is one of them.
 

92RC

Member
Roreri":1gcqesv5 said:
Great job and congrats! I'm bringing mine out to Colorado this summer and I'll face the test myself. Mine is not running rich or stinky so it sounds like if I add some octane booster I have a good chance of passing.

Colorado has had a history of difficulties with smog along the front range. It just gets trapped there, so they really started clamping down on it in the 80s. I remember clearly that you could not much see downtown Denver from Littleton.

It has its lapses but I took this picture in July 2015 and while you can't see downtown Denver due to the angle I can assure you it was visible most days when I lived in Littleton. Ignore the colors being being so surreal, I took this photo on film (because I'm a neeerrrrrdddd). My old coworker told me about some of the major Denver changes in the 80s but I believe the smog thing thus the emissions focus, the 80s bit is before my time but there were some days in July of 2021 where you could hardly see your hand in front of your face due the California wildfires.



What county will you be in? I just checked and only the counties 50 milesish of Downtown Denver require emissions checks, Boulder, Broomfield, Denver, Douglas, and Jeffco (along with portions of Adams, Arapahoe, Larimer, and Weld counties) so if you're pretty far off "the reservation" you'll not have to worry about it. That being said, I'm kinda glad I had to do it because the car drives (and smells) so much better now that it's fixed and I wouldn't have investigated further without knowing there was a problem with the car.


simple":1gcqesv5 said:
It's gross in Denver area. I work in the 35th floor and the haze of yellow is there any day it isn't windy or raining/snow

On the ground level you think it is a clear sky which leads people to believe all these clean air standards are silly.

All cities suffer from it but it is worse in certain ones. Denver is one of them.

This is good to know, I was on the 38th floor of a building January of 2016 and I took this picture, other than the Sears Tower I don't think I had ever been particularly high up in a skyscraper before that day and I was like "wow what a coooool view!" Obviously things have gotten worse again sadly.

 
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