geoduke

Last week I failed the emissions portion of my inspection in VA. The reason it failed was the NOx was over the limit in both the 15 and 25 mph readings:

15mph (limit/reading) (1046/1284): 25mph (limit/reading) (956/2237)

From reading on the forums, especially this thread:

https://www.yotatech.com/forums/show...led+inspection

From reading the above thread I think the problem may be with my EGR system as well. After looking at my truck again to check all hoses and connections, I noticed that there is an area where it looks like something was connected and now isn't. The inside of this hole is threaded also. Below is a pic of what I'm trying to explain.



I am relatively new to auto repair but I enjoy it a lot and bought this truck as a way to learn a bit more. I have the Chiltons and Haynes repair manuals but haven't been able to find any info as to what if anything attaches to this and where it goes. Please help.

miket223

That port you have circled is for CA emission spec vehicles. That is for an EGR temp sensor to ensure EGR flow when the system is activated. Federal spec vehicles don't have that sensor. Your vehicle must be a federal spec since yours doesn't have a sensor. You need to go through the diagnostic procedure to verify EGR operation. Also, check your ignition timing to make sure it is not over-advanced or else you'll fail to NOx portion of an emissions check. There are several other common problems that can specifically cause a failure on the NOx emissions. Carbon build-up on the pistons, O2S, low fuel pressure, or a bad catalytic converter can cause this problem too.

geoduke

I forgot to mention that the cel is on as well. It comes up with code #11. From looking at the codes it doesn't seem like this one would have anything to do with the emissions control system. But then again I may be, and probably am, wrong. I'm gonna go ahead and check the EGR valve tomorow and go from there.

4Crawler

iTrader: (3)

JMy 22RE had about the same readings on my first dyno test. Cleaned EGR (gun cleaning kit works well), checked all the vacuum lines for clogging, retarded timing 3-4 degrees, filled w/ 92 octane gas and retest was 40% of original numbers.

geoduke

Ok, I have to say that I am thoroughly confused at this point.

I checked the EGR valve by using the vacuum test and the truck just about died so I think it's good. I checked any hoses that looked like they had to do with the EGR valve and air was able to flow through them so I don't think they are clogged.

Next I went on to check the timing and retard it a few degrees. The first time I looked at it, it was way past 20 BTDS. As I moved the distributor counter-clockwise as far as it would go, the timing notch just made it to 20 degrees BTDS with the distributor in the most counter-clockwise position it would go. The truck sounded kinda rough and when I went to drive it, it had absolutely no power. I then returned all the settings to where they were before I made any adjustments.

I realized later that I forgot to short out the check connector. I went back, shorted out the check connector and checked the timing again. This time the mark was so far to the left that it almost couldn't be seen! I let it run for a good 5 or 10 minutes in the hopes that it would return to somewhat normal but it didn't. When the check connector was shorted I also saw that code #52 (knock sensor circuit, knock sensor, ECU) but I think that might just be a result of my earlier "test drive."

What am I doing wrong? Also the distributer at the setting that it's at right now is as far clockwise as it will go. What happens if I need to take it further clockwise?

Any help with this is much appreciated. I want to find out what I'm doing wrong and also get this thing through emissions inspection. Thanks.

4Crawler

iTrader: (3)

My EGR would kill the engine when pulled open with vacuum, but it was clogged to the point that there was not enough flow to be effective at high engine loads. It is one hing to kill the engine at idle and a whole different thing to recirculate enough exhaust gas to make a significant reduction in NOx (the result of high combustion temps) at 2500 RPM and nearly full throttle. Check and clean the passages between the exhaust manifold and the EGR valve.

Maybe the distr. is installed off one tooth. Not clear if it is working now or not.

Legacy 4Runner

Geoduke: I have the same engine with CA specs so I have the wire that comes off that EGR valve.
Similar to you, I failed the CA smog test with my other Toyota, an 87 4WD Van. Report showed that the EGR was not functional. I replaced the EGR, vaccum modulator, PCV valve, and any vaccum hoses that were cracked. In addition I cleaned out the throttle body which was full of carbon. Once all complete, I ran about 1/3 bottle of SeaFoam through through a vaccum line and put the rest of the bottle in the gas tank. I have not re-smogged it, but it made a difference in the way it runs.
Back to 4Runner V6 that you and I have, I would replace the EGR, seems simple, remove the throttle body (4 bolts holding it) and clean it with air intake cleaner. If you can get to the PCV valve, which is on the passenger side toward the back of the valve cover, replace it. It's kind of a PITA to get it, I never did! Replace the air filter too if its dirty. Run a 1/3 of a can of SeaFoam through the brake booster vaccum line. This is the hose that comes off the brake booster on the driver side and runs across the rear firewall of the engine. Follow the instructions on the bottle. When you're doing this, dont be alarmed of the smoke that comes from exhaust for a few minutes. Put the rest in the gas tank, filler up and drive it around.

Hope this helps, let us know what happens! Good luck.

menko

The other thing you might want to look at with high NOx readings is your catalytic converter. What were your other readings?

4Crawler

iTrader: (3)

I failed w/ high NOx this spring, brand spaking new cat (from Toyota even). HC and CO were near 0, but NOx was 2X the limit. Cats are not all that great at reducing NOx, at least not enough to make up for a bad EGR system (EGR's only purpose is to reduce NOx). EGR blockage was my main problem, nearly passed the low speed test, but really failed bad on the high speed (high power, high air flow) test. EGR "worked" but was just not able to flow enough exhaust gas at high engine loads to do it's job. Spent a day cleaning everything and also did a little "porting" on the EGR passages in my headers to better match the exhaust ports in the head. All that reduced NOx from 2400 to 880. That and some premium gas, and retarding the timing a few degrees.

geoduke

Is there any way to actually open the EGR valve up to clean the inside of it? I'd much rather do that than spend the $200 for a new one. The passage between the exhaust manifold and EGR valve is the ribbed tube that enters into the bottom of the EGR valve, correct? The tube in the back of the EGR goes to the intake so it would make sense that the one on the bottom was from the exhaust.

Just got done reading the entire 17 page thread on seafoam earlier tonight and yes I'll be adding some of that for good measure as well. The pcv valve was replaced a few months ago so thats something to check off the list. It was a total hassle seeing as how the gasket was no longer made of rubber and broke apart easily. It was like playing the game "operation" towards the end trying to fish that thing out.

4Crawler

iTrader: (3)

On my 22RE, I cleaned the EGR with a gun cleaning kit (assortment of round wire brushes) and gun cleaning solvent (dissolves gunpowder, i.e. carbon, deposits). Can't really be opened up, but you can get at most of it. Clean any part of the passage you can access. I shot gun cleaner into the passages then blew it out w/ compressed air a number of times. Main clogging in mine was right at the exhaust ports and at the valve and connection to the intake.

yamarocket630

If he only failed for NOx, the cat should be fine. While a 3 way catalyst does have NOx reduction capability, NOx is mostly controlled in the combustion chamber.

Remove your EGR valve and clean it and all the tubes/passages. Make sure all the vacuum hoses are connected correctly and not leaking or collapsed. Run your favorite brand of injector cleaner for 2 tanks, and do a good combustion chamber cleaning. On a healthy engine, NOx should be way less than the limit - usually 50% or less-

geoduke

I just took it in for another test and failed again. This time I only failed the 15mph portion which seems kinda strange so I'll post the complete results of both tests below:

1st Test
15mph 25mph
Limit Reading Limit Reading
HC (155/ 16) (151/ 83)
CO (1.31/ 0.05) (1.68/ 0.27)
NO (1046/ 1284) (956/ 2237)

2nd Test
15mph 25mph
Limit Reading Limit Reading
HC (155/ 44) (151/ 89)
CO (1.31/ 0.02) (1.68/ 0.19)
NO (1046 /2134) (956/ 951)

Over the past week to try and get this thing through I took apart the EGR system and cleaned what I could of it. I was suprised to see that there wasn't too much deposited in the insides of the passageways. I would describe it as a dusting. The outside of the rod that goes into the intake was caked with the residue, however. I scraped it off with a wire brush. I added a can of BG44k and have driven about a quarter tank with it in there. I also did the seafoam treatment, adding 1/3 can to the tank and 2 treatments of 1/3 to the pcv hose. I retarded the timing slightly also.

The results of the test are strange because while the NOx decreased in the 25mph test they almost doubled in the 15mph test! Any ideas?

yamarocket630

What were the O2 readings? If they were high, suspect a lean running concern. If they were not high, then either the EGR is not flowing enough or you have hot spots in the combustion chambers. That can be caused by a lot of things, but usually by injectors with a 5hitty pattern that dont atomize the fuel well, or carbon in the chambers.

Is the exhaust all stock?

Do you have access to another 3.0 to do some testing? (or maybe some other Yotatechers can help here)
Here is a quick test for the EGR Record the vacuum at idle with a gauge... open the EGR by applying vaccum to the valve, recheck engine vacuum with it open. If the EGR is restricted, the vacuum will not drop as much on your engine as on a "known good" 3.0l.

edited for clarity

4Crawler

iTrader: (3)

One slight problem with the early EGR setups, at least on Toyota, is that the EGR does not fully open until about 2000 RPM (at least that is where the FSM tells you test test that it is open). But the 15 MPH test is often well below 2000, so the valve may just be opening down that slow. Suppose you could re-plumb it for the test or at least make sure it is getting the proper signals to open that slow. I think there early EGR systems were designed to pass the no-load sniffer tests that were in effect when the smog control systems were designed. Then the smog tests have gotten tougher and it is harder to get the engine to pass. Also, see if you can back off the timing, I retarded mine about 3-4 degrees. That'll cut the NOx. Another thing I tried that helped was to make an exhaust restrictor plate:



Sits between my header and downpipe and blocks about 1/2 the cross-section to help boost backpressure to force more exhaust gas back through the EGR. Doing the EGR cleaning, timing change and plate dropped my NOx from 2200 to 880 @ 25. My 15 test was just over before and well under after.

yamarocket630

If the testing station is setting things up correctly, his truck is only required to pass emissions standards for the year it was built.

4Crawler

iTrader: (3)

Correct, the actual emissions readings are model-year specific, so my '85 has higher limits than say a '95 would. However, the dyno test is in some ways harder and some ways easier than the old no-load test. The dyno actually make the HC and CO readings drop on a well tuned engine, if the O2 sensor and ECU are working right, they end up near 0, at least mine did, while on the old no-load tests, I was up near the max limit on those.

The place the dyno tests are harder is the NOx, they are just not set up right for the Toyota design. EGR opens too late and the plumbing on the EGR is way too small to really do a good job at full throttle settings. On the old tests, the NOx was never measured and at no load, it would not be a factor at all.

geoduke

I'm not sure I even see O2 readings on here. The only other test info is:

1st Test
15 mph 25 mph
RPM 2816 1762 valid
Dilution 14.6 14.7 valid


2nd Test
15 mph 25 mph
RPM 1603 2593 valid
Dilution 14.5 14.6 valid

As far as I know, it's all stock. I bought the truck off a friend about a year ago. It runs great.

edit: forgot to change numbers on my 2nd test after copy/paste

yamarocket630

O.K., sorry I misunderstood you. Yes a loaded test will be harder to pass than an unloaded test. Good idea on that exhaust restrictor too. Ya do what you gotta do.

geoduke

I just wanted to give a heads up on what ended up being the problem in case someone else has trouble like this in the future. I passed emissions today after getting the truck back from the dealer. It turns out that the EGR valve was not getting any vacuum. From what I can tell based on what the deler told me was that one or more of the hoses was hooked up incorrectly and basically caused the EGR system to not come into play. I bought this truck off a friend who bought it off someone else so I guess this is just one of those things I'll be running into every now and then.