1992 SC-300 checking in.

I failed the emissions portion of the Texas (Harris County) inspection. All of the emissions were very low except NOx.

@15mph (max/mine)
853/630

@25mph (max/mine)
773/2576

To my simple mind it would seem that NOx would be highest at low speeds since the car is running cooler than at high speeds, but mine was well below at low speed and over 3x the maximum at high speeds.

I went to a place here in Houston and he wants to do $2000+ in repairs (parts and labor). EGR system replacement, VSV replacement, O2 sensor replacement and some other things; basically the entire emission control system except the front and rear catalytic converters.

Is this reasonable?

 

Run seafoam. search for seafoam thread.

Should clean up enough carbon to pass.

 

I took off the EGR valve and cleaned it (it was absolutely filthy, I can't believe that much nasty carbon could have even been in there). The filter is still disgusting, couldn't find a good way to clean that.

I'll do the whole Seafoam thing next week. It seems pretty intense.

 

Dump a can in your half-full gas tank. Run till 1/4 tank.

 

Won't I need to replace the spark plugs afterwards?

 

after seafoam, change the oil as it will get some blowby into the oil, and seafoam is a substance which can reduce the lubricating properties of oil. If you can also get your hands on it, Amsoil Power Foam is badass too

 

All right, I took off the EGR valve (or at least the top part of it with the three hoses coming in the sides) and cleaned that out really well and ran some of that cleaner stuff (not Seafoam, I put it in before I posted here and Seafoam was recommended) in the gas tank, made by Pennzoil I think.

Doing that cut my high-speed NOx in half, but it increased my low-speed NOx.

New reading:
@15mph (max/mine)
853/1229 (up from 630)
@25mph (max/mine)
773/1420 (down from 2576)

What I'm thinking of doing is getting two aftermarket cats (Magnaflo 53005 & 91005) and having them welded on. Anyone think that would help it out? Also, will those two cats (front & rear) play nice with the stock 1992 SC300 exhaust pipes and mufflers?

 

how many miles are on your SC? anything over 100,000 is pretty much guaranteed that your cats are not functioning where they should. the aftermarkets should help out.

 

~127,000 miles

I ordered the Magnaflows (53005 & 91005) online. I talked to a local shop and they're quoting me $85 each to take off the old ones and put the new ones on (all labor, I provide the parts (obviously)).

 

No he is ripping you off BIG TIME.

You probably only need to check your EGR and MAYBE O2 sensor. This scumbag is going to replace a lot of working parts.

In some cases you have to replace egr if original is beyond salvation.

www.newlexusparts.com

You could probably do egr yourself to, its time consuming but not difficult.

 

Thanks!

What is the part of the EGR that sits on top and has little hoses coming out?
It was a simple matter to remove that (no tools needed) and I realize it isn't the full EGR system, but just for interest's sake I'd like to know what it's called.

 

It turns out that I've only cleaned out the modulator. The filter is absolutely filthy.

I am going to do a Seafoam treatment (I've already done one in the tank (emptied)) through the PCV line, but I'm wondering if there's any way to get Seafoam to the EGR valve directly without taking it apart. Would pouring some down the line that runs to the bottom of the modulator work?

 

If you cars a auto heres a quick check:

Take the vacuum line off the erg valve. (not the modulator) Have a friend load the engine
in drive to about 1500 rpm. (2 foot) Wet your finger & see if there's vacuum on the line.
Will be slight vacuum but you will know its there. If vacuum is present, the modulator &
vsv are working ok.
If you have a hand vacuum pump, apply 10-15" directly to the egr valve. Does it hold
vacuum? If yes, plug the vacuum hose to the valve w/ a golf tee or similar. Start the engine
in park & apply vacuum again to the valve. The engine should shake violently or stall.
If the engine shows little change the egr port going into the intake is clogged.

BTW what are the HC & CO readings?

 

I am about to ask some stupid questions, so I took a picture and color-coded some tubes and marked some others so you can follow as my slow brain tries desperately to work its way through this.



As you can see I have labelled two tubes with question marks. I have a pretty good idea what they are but I'd rather ask before guessing, if you'd clear those up for me that would be great.

Now, is the "vacuum line off the erg valve. (not the modulator)" one of the ones I color-coded?
If so, which color?
If not, where is it?

 

#1 looks like the throttle cable, #2 is the vacuum hose the goes to the power brake booster.
The egr valve itself only has 1 vacuum hose connection. (on the top)
I beleave its the pink hose.