ok went through emissions again and failed even worse for nox. i seafoamed it put fresh 91 octane gas and rubbing alchol. i think i know what it is if i am right i put a 3.4 in my truck which has a valve over lap egr system and do they still need back pressure in the exhaust system to make it recirculate in the cylinder thanks

 

if it is failing due to nox. then you need to check your egr, timing, o2 sensor or exhaust leak , or the t-stat and cooling system plugged up. no need to due an engine swap just to pass. it would have to be one of these problems.

 

i did a engine swap. i have the 3.4 in my truck witch is failing

 

what all have you done to the motor?

 

nothing no mods at all i just need to know if you need back pressure to work the egr on a 2002 3.4l

 

i dont think so. what about you exhaust work?

 

not so good its preaty bad i need to fix it

 

if the exhaust has a leak before the o2 sensor that could be the problem. did you fail the idle test or the loaded test? nox testing failure is due to high combustion temp. so the next question is if it was the idle test or the load test.

 

if you know what all the reading are for the test i could probably tell you more what is going on.

 

they dont tell me on the ticket in az all it says is allowed 3.00 and i got 3.70ppm

 

hc grams per mile mine .99 allowed 1.60
co grams per mile mine 9.87 allowed 20.00
nox grams per mile mine 3.70 allowed 3.00

 

Grams per mile........holy s**t, I haven't seen that scale of emission readings in 20 years!! It has been PPM (parts per million) since at least the early 80's.

Thanks for the memories......

 

your welcome anybody got any ideas on what i can do

 

if everything else is good and yours is it is deffenently an egr problem. there is the valve itself, the vsv., and the modulator. or the vacuum for the system.

 

My 4runner failed smog on high NOX 4 times in a row. The smog guy kept saying it was the EGR valve, so I cleaned out the EGR valve and the whole EGR system. Still failed, turns out it was a bad catalytic converter. I put a new cat in it and smogged it 5 miles later and the truck hardly had any emissions at all. So when all else fails try the cat.

 

ok i will try that when i get a chance

 

before you go out and get a pricey cat and have a hell of a time with 100 year old rusted bolts.. hit your cat with a rubber mallet (car off) and you should not hear any rattling inside the cat.. If you do then your cat is garbadge and you need another one.. the fact that you hardly failed nox tells me its probably not your cat but it MIGHT be on its way out.. do the rattle test then tell us

 

cat is good i looked at it about a month ago all clear and no rattlein but it is also the 3.0 cat that is still on the truck so that might have somethin to do with it barley not passing.

 

The stock pipe size is just under 2" I heard the recomended size for the 3.4 was 2.5" Perhaps this is causing the engine to run hot and pullute more?

just thinking out loud here..

 

maby but i couldnt see it causeing that