1989 Camry Failed Smog Test

[alistaircookie]

For the first time in the 23 years we've owned our trusty Camry, it has failed the California emissions check. I'd like to fix it myself, but I don't know where to start. I'm hoping some of the fine people here might be able to help.

Here are the details of the smog check:

The NO output is fine.

It passed the HC check, although it was very close to being out of range on the 15 mph test (84 ppm, with 85 ppm being the maximum allowable).

It failed the 25 mph CO% test, and almost failed the 15 mph CO test. (At 15 mph, 0.53 measure and 0.54 allowed. At 25 mph, 0.56 measured and 0.45 allowed.)

The cars runs pretty well - at least as well as it has in the past five years. It has gotten a bit sluggish overtime. It is regularly maintained (it got a new starter and fuel pump in the past year). It does leak some oil, but other than that, there's nothing obviously wrong with it.

I should probably also mention that I drove the car for a while before bringing it into the smog station. The car was definitely hot when it was tested. Also, I cleaned out the throttle body with Seafoam in the last year, so I don't think it's merely an issue of throttle body gunk.

So where should I start? What should I look for?

['88 All-Trac]

When was your last tuneup? Your last O2 sensor change?

Your cat may be getting old. We have a '91 that in no way would've passed smog. Checked the cat, it was waaaaay plugged up.

My solution? Move to New Mexico.


But on a serious note, check the plugs... Run the tank until it is empty and then put in maybe a gallon of E85- that stuff is so terrible and inefficient as a fuel that it cuts down on all of your emissions. As soon as you get home, drain that crap and put real fuel back in. It'll have your 20-year-old gas tank rusted through in no time.

Maybe do a fresh tuneup and toss in a new air filter. Clean up not just the throttle body, but the IAC valve located in the bottom of the throttle body. There is a small hole in the bottom of the inside of the TB- spray some carb cleaner in there and let it soak really well.

[alistaircookie]

Thanks for the response.

The last full tuneup might have been a year ago. That's when it last got new spark plugs. Perhaps I should put in new plugs again?

The timing is fine. What else usually gets checked in a tuneup?

I suppose, with the aid of a friend with the right tools, I could do a full compression and leak down test - but that's a project for later.

The oil was last changed a month ago.

I suppose I could put in a new air filter too. Would that make much of a difference?

The O2 Sensor hasn't been changed in ages. The last one went bad years ago, and I've had no reason to think the one in there is bad.

When I cleaned the throttle body, I tried to really clean out the IAC too. Perhaps I should clean out that whole area again.

Still, these all seem like tricks for getting the car to just barely pass smog. I'm wondering if there isn't something more wrong. The car used to pass smog with low numbers across the board. Do these high numbers indicate anything more than a bunch of old and gunky parts?

I've thought about checking the cat, but how do I do that? Isn't it welded in?

Jeremy

[Doctor J]

When "slight enrichement" is noted I will do the following:
Check the O2 sensor votage at diagnostic connector (Vf and E1); it must fluctuate at least 8 times in 10 seconds at 2500 RPM
Check the computer for trouble codes
Check the resistance of coolant thermosensor at normal operation temperature it must be less then 300-200 Ohms
89-90 California 3sfe engine may use heated oxygen sensor (has 4 wires); failure of the heater makes this sensor dead

[white90dx]

It is a good idea to replace the O2 sensor (main one, not the secondary if equipped). What about the age of the rest of the ignition system? That might also be suspect.

The cat is removable but by now you would probably break a number of bolts to get it off there... hopefully you don't have to go that far. I believe there are bolt-on replacements though.

-Charlie

[Doctor J]

There is also a second cat under car (can be bolted or welded, but it is a cheaper one)

['88 All-Trac]

Yes, second cat is cheaper to replace. O2 sensor does not usually throw a code when it fails, they just "slow down" and don't give the computer a good reading. For what they cost, it's worth a shot.

[alistaircookie]

So I did a tuneup and oil change, and replaced the O2 sensor today - and it still failed smog.

I'm at a loss for what to do next. My local mechanic is of the opinion that there's nothing "wrong" with the car, and that some parts must be very dirty and carbon covered internally. He thinks it just needs progressive cleaning, starting perhaps with the EGR.

He also says that since the NO numbers are fine, it's probably not the catalytic converter causing the problem.

I don't know about any of this. Any other thoughts?

['88 All-Trac]

Seafoam the engine. Use a vacuum line to pull it into the intake just enough to stall out the engine- but do so slowly or you risk hydrolocking it. Let it sit for a good five minutes and restart. It'll smoke like crazy but should do wonders to clean the engine out. I got a good 20hp boost with my All-Trac. Poor thing was running 240k with poor maintenance and having never been cleaned. I'm sure yours is in better shape but it's worth trying.

Try cleaning the EGR. They regularly get plugged on these.

[66conv6]

We replaced the egr of our 87 camry 3sfe with an oem part and that solved our problem easily for california smog.

[Doctor J]

You need to make sure the engine is in the closed loop before proceeding with repairs

[alistaircookie]

Good news, the car now passes smog - but it wasn't easy to get it to pass.

The O2 sensor, plugs, wires, and distributor cap were replaced. The EGR and throttle body were cleaned. We did an oil change and replaced the oil filer and air filter. And after all that, it still failed.

Finally we replaced the catalytic converter. Only then it it pass.

The original emissions numbers are in the first post of the thread. Here are the numbers now:

HC at 15 mph: measured 44 ppm (max allowed: 85).
HC at 25 mph: measured 28 ppm (max allowed: 67).

CO at 15 mph: measured .50% (max allowed: .54).
CO at 25 mph: measured .24% (max allowed: .45).

NO at 15 mph: measured 4 ppm (max allowed 565).
NO at 25 mph: measured 5 ppm (max allowed 522).

Thanks for all your help.

[Grego 92]

Congrats! hopefully whatever caused your cat to go bad has been solved also so that it doesn't mess the new one up.