[ToyoZone]

A month ago I took my truck to get it smoged and failed miserably. In fact, my truck was considered a "gross polluter".

I replaced a few things (one VSV, EGR valve and modulator, vaccum hoses) and at least the check engine light went away. I did complete tune-up and headed to the smog station again and failed again at 15mph only. I asked them to do a diagnosis but couldn't find anything wrong.

But the guy suggested replacing the Cat which I probably will do (its been 4 years since it was replaced) and about 99K miles.

I have an aftermarket air intake which the mechanic said could be a problem. Not because it is an aftermarket system, but because it sits pointing down and sideways. He thinks the flapper in the Air Flow Meter may not be moving freely.

I am gonna try to post a picture of the emissions report to see if anyone has any idea what could be wrong.

Any help would be appreciated.

 

[V62WDLongbed]

Can you adjust your air flow meter to be in a horizontal position again? I'd fix that before I'd invest in a new cat.

 

[ToyoZone]

emissions

That is my plan. I will adjust the air meter first and re-test since the test shop is one of those "pass or re-test free". If it doesn't pass then I'll move on to replace the cat.

Thanks for the advice.

 

[Jayota]

If you can, post up your results for all the feilds. Usually if say your o2 sensor is bad, it will effect your results in the other sections. Mine failed with high nox, all other sections VERY low. Thus the EGR valve is the culprit.

But say your HC are pretty high, an o2 sensor might be causing some trouble.

Also if you can, unbolt the cat (if its an oem style) or remove it and check the screens. If they are damaged get a 80 dollar highflow magnaflow.

 

[ToyoZone]

emissions

I don't see an option to post pictures anymore, so I don't know how to go about it.

But yes, I got high readings on the nox. Based on what you are saying the culprit is the EGR valve. The guys doing the diagnostics said it was ok, but they could be wrong. I checked it myself as indicated in the service manual and does what it is supposed to do.

If you know how to post a pix let me know.

 

[Jayota]

Go to a host website:


www.photobucket.com ( what I use)


Upload your photo, paste the URL here like this

with no spaces.

Have you cleaned your EGR passage?

 

[Vicoor]

just type in the results

 

[ToyoZone]

results

Here is what the report spitted out:

--------------HC(PPM)------ CO(%)------NO(PPM)
Test---RPM max ave mea max ave mea max ave mea
15mph 1655 127 34 180 0.78 0.11 0.61 1031 260 1795 FAIL
25mph 2685 108 23 79 0.99 0.10 0.36 891 217 788 PASS

A second person told me today it is the EGR and that many times testing it according to the service manual doesn't really tell you if it is damaged or not.

What do you think?

 

[Jayota]

I don't think its the EGR, all your results are pretty high.

How old is your o2 sensor?

 

[ToyoZone]

sensror

I think it was replaced about 5 years ago.

 

[Vicoor]

Make sure your ignition timing is correct.

The High NOx could be attributed to advanced timing as well as EGR problems.

The egr valve may be working but the passage in the head could be restricted

a lazy O2 could also cause problems like that. at lower speeds it may not be hot enough then later in ther test at a higher rpm it may work better.

really you need to test these systems to find the culprit.

 

[kemper]

i had the same problem with my wifes car high nox replaced the o2 sensor and i passed ..

 

[Pb]

The dealership and muffler shops will charge a ton of $ for cats. I got a new SS Magnaflow Cat for less than $100 online.

BTW, I've got some good O2 sensors for sale. Not sure if they will fit your application. http://www.toyotanation.com/forum/showthread.php?p=2202744#post2202744

 

[Jayota]

If PB's stuff doesnt fit your truck, and you want to replace the o2 sensor. Check out www.sparkplugs.com Very good prices.

 

[Pb]

Try to stick with Denso. Some Toyotas don't like Bosch sensors.

 

[ToyoZone]

emissions

Thanks for your feedback.

I just cleaned the EGR and will replace the O2 sensor this week to get it retest it. I'll keep the posting updated.