2000 Toyota Tacoma 3.4 V6 failed NOx GPM emission test

Took my truck into get an emission test and failed for NOx GPM. Limit is 2.000 and its 3.2719. No check engine light and no diagnostic trouble codes. Went to autozone and the guy suggested run seafoam through the intake and oil also CRC Guaranteed to pass emission test formula in the gas tank. Ive used seafoam before through the gas tank never in oil or the intake yet. Havent used CRC emission test formula yet. Didn't notice a difference when in the gas tank over the times ive used it. Recently changed oil about 3000 miles ago but will do anther change sooner last time was pretty nasty. So question is with these products will that fix my problem or is it something more major?

 

Would any of the mods I have done be something to do with that? It has 234,300 miles on it. Only modifications to the motor would be air intake system, k&n oil filter, 10w-30 lucas oil, 180 degree thermostat. I think that's it.

 

Are you on the original catalytic converter?

 

180 thermostat will hurt.
I'm not sure at what temp the ECU kicks into closed loop, but 180 is too cold.

 

The thermostat was a Murray thermostat bought at Autozone few years ago and i think it was a 180 i'm not sure. Will check tomorrow to make sure. About the catalytic converter it is not the stock one. From the Cat back was replaced few years ago due to a stupid mistake. The shop used the same pipe from the cat to the muffler. Cat was new muffler was new and pipe after the muffler was new. Stock O2 sensors there pricy for me at the moment.

 

Also a quick question. Emissions test sensor description said engine coolant temp was up to 91 degrees C or 196 degrees F. Haynes manual only gives me the thermostat rating for the 3.4L which is 176-183 degrees F. Is the engine coolant temp supposed to be the same temp as the thermostat?

 

Get a Toyota cat and try changing air filter and oil before testing

 

The stock cat was bolted on the shop welded on the new cat so i would have to cut it off and weld on another. Air filter is clean i paid over 60 bucks for a k&n that fits the stock air box and recently cleaned it few days before testing. Oil was changed about 2000 miles ago with Lucas 10W-30. After getting my test results i bought a can of seafoam to run through the intake and oil but havent done that cause cant afford another oil change yet.

 

sorry oil was changed 3000 miles ago as i said in the first message.

 

I failed NOX before when I was running a cheap OE style cat. Borrowed a friends oem 3-way cat and passed. Not sure if thats your issue though but just a thought. I don't think ur truck has an egr to worry about ?

 

Ok first and formost grab some carbcleaner and electrical cleaner from the parts store. Clean the throttle body with carb cleaner, then the MAF with electrical cleaner.

Then get the car warm, pull the line off the master cly, this should go to the intake manafold. This is a good place to put the seafoam, use about half the can. see directions on can, dont put in oil or gas yet.Then shut the truck off, let sit of 10 min or so then go drive the shit out of it untill it stops smoking.
You can re do the seafoam if its really bad.

Other peoples seafoam
http://www.tacomaworld.com/forum/1s...d-seafoam-my-old-96-almost-200-000-miles.html

Then after all of that I would look at pulling your plugs and cleaning them off carb cleaner.If there rally bad replace with OEM.
O2 sensors, pull them out and clean them with electrical cleaner, reinstall.
Pull the EFI fuse on the fuse block, to reset computer.

Drive around and clean all of the stuff you put in the tank, then go take the test with fresh 87 or 88 gas.

The other thing you can do is buy a OEM toyota t-stat, is cheep and easy to do.

Good luck

 

The temp for the thermostat is not the engine operating temp. A 180DEG thermostat is simply designed to open when the coolant behind it reaches 180DEG. The engine can still operate higher. The idea of the thermostat is to maintain a good operating temperature for the engine. It helps to heat the engine up faster, and prevents it from getting too cool as well. Without a thermostat your engine could easily run as low as 170DEG, which is still high enough for closed loop, but will increase NOx emissions.

Would not suggest using the brake booster vacuum port as it only enters the intake at the #3 cylinder intake runner. You would have a really clean intake runner for cylinder #3, but the other intake runners and cylinders would not get the seafoam ingested into them properly.

 

Would not suggest using the brake booster vacuum port as it only enters the intake at the #3 cylinder intake runner. You would have a really clean intake runner for cylinder #3, but the other intake runners and cylinders would not get the seafoam ingested into them properly.


Good to know! I will look for another port higher up. This is port I have been using.

Thanks

 

just a idea, when I did mine, I got a small hose and used the PVC port, it seemed to work.

 

I just serviced my intake tube and filter not to long ago was before the test. Everything to the throttle body is clean. MAF is clean, throttle body clean, filter clean. Intake has not been cleaned will do that hopefully tomorrow with seafoam it looked bad when i took off the throttle body. Also with my intake set up it would be a lot easier to just take off one of the clamps to the tube and poor the seafoam in there slowly doing 1/3 of the bottle twice then last third of the bottle poor in and stut off the truck for 5 or 10 min. Start up and let the smoke roll. Instead of figuring out which hose leads where. Also put some in the oil run it for awhile then do oil change, clean spark plugs, MAF, o2 sensers etc. Plus i have til this friday to get it to pass otherwise gotta pay again. We'll see what happens tomorrow with pay day. Keep in mind i gotta work with my budget cant do everything at once. Working part time sucks.

 

never, never shut the motor off while doing a foam! its best to get the truck right on the road and really run her, you dont want that soot and crap building back in the exhaust

 

See that's what I was thinking then someone said that about the seafoam. 1/3 in slowly for the first 1/3 of the bottle same with the 2nd 1/3. On the last 1/3 pore it in let sit 5 min then run it. I thought if you dump in its just gonna sit there and drain into the oil.so I'm gonna run the whole bottle in then drive it around get all that carbon build up out. Then do oil change, spark plugs, and clean o2 sensors.

 

Sounds like a good plan!

 

Ran seafoam in the intake just a bit ago and ya it was a good amount of smoke coming out the exhaust. Did not shut off the truck while doing this. Drove it around and now gotta do the clean up steps and see what the emission tests say. Oil, plugs, o2, etc..

 

Just got done with the re test emissions failed again. NOx was only brought down to 3.0565 from 3.2719 after seafoam treatment in the intake limit is 2.0000. Anything else I can do after all of that work I did? Gonna try different spark plugs I'm running denso platinum tt right now.