My 4Runner just failed CA emissions and I have no idea what to look for. It passed every other area, just running a little rich but not enough to be a gross polluter. I'm going to post the printout in hopes someone here can give me a direction to go with this thing.
The engine was rebuilt in 2015 and I have had minor problems with it since then. I replaced all the vacuum lines with silicon and appear to have no leaks. The smog guy couldn't find any problems or leaks. I've recently replaced the TPS. I don't know if that needs to be adjusted.
I don't know if this richness can be caused by an air filter problem, but I'm planning to replace that again. Those things can't be too new, I reckon. I just don't know what else to do with it or what to test or diagnose.

 

I forgot to include these details:
1990 4Runner 3VZE Auto trans, 4x4,

 

Well, the good news is you passed NOx. (Those can be harder to control.)

This article might help: http://www.cygnusx1.net/Media/Supra/...taTech/h56.pdf High HC and high CO point to too rich, but your CO2 says you're "close."

The first thing I would look for is "missing." A "cylinder efficiency test" could help. (pull the plug wires one at a time; the one that produces no change is doing no work and dumping fuel into the exhaust). Or use your ear. Next, I would go ahead and replace the O2 sensor. Once you do that, in the spirit of checking the easy stuff, assure that you're getting the VF1 "flop" about 8 times in 10 seconds. http://web.archive.org/web/201003261...01heatedox.pdf

Remember that the O2 sensor (via Learned fuel trim) is the final arbiter of mixture. If your VAF is way off, the O2 sensor will compensate, unless you're so far off that you throw a code. At this point, I wouldn't horse around with the TPS or the VAF.

Good luck!

 

I have a 95 4Runner that has the same drivetrain as yours. I bought it from a charity auction. Someone had donated it because they could not get it to pass smog. When I tested it I got a fail very similar to yours. With an EGT probe I worked out the catalytic converter was not getting hot enough for the test. I took it on the freeway at 70 with the OD turned off for about 10 miles and drove it right into he smog shop. It helped the shop knew what I was going to do and was waiting for me. They hooked it up and it passed easily.

So maybe your just not getting the cat up to temp.

Jake

 

We used to "hot lap" the older Toyotas to get the cats hot, too. Made a difference. The cat cools fast, so it can't sit once it's back at the smog station.
I fill mine up with Chevron super unleaded before a test, but any "top tier" gas should suffice.
I assume you have Denso ignition components( cap, wire set, etc) and regular ND or NGK plugs?

 

Before I do my bi-yearly I visually check my plugs. Easy enough on a 22RE, I don't know much about the 6cyl. I probably replace mine too often, but 4 denso's are like the cost 2 gallons of (west coast) gas.

Also, if I have to sit in a long line, I try to keep the rpms in the 1K range. I have no idea if that actually helps - it's not highway rpms - but I also knock on simulated wood 3 times.

I think the best proactive thing is to keep track of is mpg. That has never failed to show me that I have a slight/lowering performance degradation in the system.

-jim

 

Thank you guys for your responses. I dropped this post last night and went to work swingshift, so I didn't get a chance to work on anything, but I have a bunch of things to look at today and a better understanding of where to start. Thanks again.

 

Make sure you post an update when you have it. I am very curious to see your outcome and what you think did it.

Jake

 

I'll be sure to do so. The questions I've never asked were usually answered in these forums, so I'll help when I can. I just have to wait until next payday because these smog tests are unfairly expensive. I wish there was an app I could get for my phone that would test my exhaust, but I reckon we're still a few years away from that kind of utility.

 

What brand of sparkplugs? And what gas station do you favor? And reg or super unleaded?

 

So this is an update. I still haven't gotten it through smog yet. I drove it to Utah and back and it ran wonderfully the entire trip. A few weeks later it started throwing engine codes and I replaced one of the induction hoses and cleaned up the idle air control valve, so now I can adjust my idle speed, so that's something. I had some opportunities to work overtime and other expenses, so I never quite got around to getting it smogged again. I put some additives through it and probably 20 tanks of gasoline so far and it's still running great, but I've got an exhaust leak to fix now. The cause of which is my fault the result of a poor repair, but my workshop is outdoors and California has had some remarkably wet weather, and I'm not keen on laying on a wet floor while working anyway, so there won't be any work done for a few more weeks.

To answer the spark plug question, I put in Denso plugs and I'm using regular gasoline mostly from 76, but occasionally from other places. I'm thinking to run a few tanks of super before the smog test though to give myself the best edge. I love having and working on these older vehicles, but they keep needing more work. At least I don't have a car payment though.

 

I put a high performance ignition coil in my 1990 pick up. An MSD blaster 2. It's much more responsive, has more power, seems to have better gas mileage. Seems like that could only help with emissions. It's California emissions legal so that can't hurt. They give you a sticker to place next to it that says it's certified to be legal in all states emissions. I install them on all my vehicles and always had good results. The stock coil is super weak, I think like 8k or 12k or something volts I want to say. The MSD coil is like 45k volts. I can tell it's just getting way more spark to the engine. And I use the iridium plugs so they don't break down too fast from high voltage and very hot spark. Something to at least consider if you run out of options. Who knows maybe it will be that last bit of help to make the difference.

I grew up in California, my truck actually came from there, and I used to borrow it from my Dad for years at a time since I'm out of state and he never used it anymore. Without the truck even there he'd always get it smog test passed anyway. I used to have all kinds of non emissions passable hot rods and trucks I'd supe up when I was young and living at home. My Dad always found someone pass them (funny enough my Dad was retired navy and law enforcement). I'm not saying you should, because that would be illegal. But I'm just saying, if you need to buy time to figure it out....