so i have an 86 4runner and i live in el cajon california
i took my truck to get it smogged and failed. i have been goin to test only stations. every thing passed except NOx (1615) and i needed 1000 to pass
so the 4 other times i took it to smog i got readings such as 1265, 1587, 1676, and lastly 1845.....

-i cleaned the egr
-put new ngk plugs and wires in
my mechanic bypassed the bvsv valve (this reduced nox greatly) thats when i got the 1265 reading and when i reconnected it the reading went up to 1845
-timing was set to 5 deg
-new 02 sensor
-compression is 135
and i did the infamous seafoam treatment (half in the oil and half in the gas) ran quite well actually

i disconnected the egr from the engine itself and felt for exhaust comming from the hole and there was only a little?
there is only a slight vacume comming from the hose that connects to the egr when i rev it.
when i did the vacume test for the egr my truck studders but doesnt die...

so basiclly i stuck. and i really need my truck. any help would be greatly appreciated!
thanks yota tech

 

Try replacing the pcv valve.

My guess is the 135 psi is your problem, thats pretty low.

Do you know whats causing it to read low?

 

Try locking it in 4x4 so they cant change it out and get them to do a special vehicle two speed tail pipe idle test. Well in Canada it works.

 

Run your car down to a gal of fuel add one galon of denatured alcahol (home depot) go to smog shop and i bet you a million dollars you pass , after test fill up with reg fuel , This is a full proof method that i use in california witch has the toughest standards in the us . Try it pass smog and then fix your truck peace

 

I have also heard of that trick using acetone.High nox is high combustion chamber temp.You could try advancing timing to see if that affects anything.Or a lower temp thermostat.I have seen guys pull a thermostat and run straight water in the radiator with a little timing adjustment to get them to pass{obd 1 systems are pretty basic}.I think your converter might be taking a poo,but some of these tricks might get you to slide by.

 

im not sure why it is that low
would a busted pcv valve cause low compression?

 

i first want to say thanks to everyone thats viewed this thread
i would try adding alcohol or acetone but wont that mess things up?




ok is the pcv valve supposed to be this loose?



my mechanic bypassed the bvsv valve



is the black tube supposed to be unplugged (if you see the top small black tube you can see its plugged) there is a mad leak coming from the bottom one and when i plug it with my finger the engine idle slows

 

denatured alcahol is a marine fuel and burns clean it does not harm your engine especially if you fill up after the smog test ive done this on my 22r and three other cars with no prob and pass with flying colors

 

You need a new pcv valve and grommet. Also that vacuum port is supposed to be pluged if no hose is connected to it. How did your mechanic bypass the bvsv? More pics?

 

I hate to tell you this but I went through the same problems last summer with my '89 3.0. You have low compression and nothing you do will fix that, except fixing the problem. Mine turned out to be burned exhaust valves. You have several vacuum hose issues and they need to be solved. I pulled my heads and had them rebuilt with all new exhaust valves and seats. All 12 guides were replaced and the intake valves were reground. The heads were milled flat and all valve seals were replaced.

I had virtually no wear (after 211,000 miles) on the cylinder bores and almost no leakage past the rings.

I reinstalled essentially new heads and passed emissions with like-new numbers; all near zero. I now have 232,000 miles and all is well.

The bypassed BVSV causes the EGR system to fail. This will normally cause a failure in an emissions test automatically, if the tech is doing his job.

If you want your engine to work properly, get the engine compression fixed and make sure the vacuum hoses are all connected as designed. Even a 3.0 really does work great when it has normal compression and properly connected systems, like when it was new. All the work-arounds are like taking a big pain pill when you have a broken arm--takes away the pain but doesn't help the problem at all.

Good luck,

Bugs

 

What are the other emissions readings? CO, HC, O2 and CO2? Oh, wait, you said you passed the others. So, if you're only failing NOx, and the EGR is operating properly, your only other point of failure is the catalytic converter.
Been there twice myself.

This little puppy:



passed HC, CO, CO2, and O2 just fine, but failed NOx... can you guess why?
(hint: no catalyst in the converter)

 

ill check into a new pcv valve

but i think it could be valve or ring related because my oil consumption is a quart to every 200-400 miles...an when i start my truck sometimes (hot or cold) it shoots a watery/oily liquid from my exhaust...no smoke though. thanks for the adv bugs1961

i was getting in the middle with CO and HC and with o2 it was like .01 abecedarian

But sadly i really cant afford to make any major repairs (or anything over 50 bucks lol) so im non opin my 4runner and sellin it and getting a 1990s toyota pickup (5speed!)

 

I bypassed the VSV on my truck too. All it does is lets exhaust gas recirculate when it normally wouldn't, which is at idle and full throttle.

 

Ok stop, I failed emissions 4 times. Had a chevy 350 with no cats or emissions equip. 800 cfm 4 barrel and HEI dist ..

I ran the tank to 1 gallon of fuel and added 4-5 bottles of 99% isopropyl alcohol from fred meyer. $1.99 each.

Let the vehicle warm up, drove it down the freeway an exit or two and headed straight to the emissions place. Made sure idle was at 1100 (limit for testing) and when I did the dyno test I made sure I was going faster than they wanted but within range.

Passed with flying colors.

Retard your timing a bit so it burns everything off.

Change your oil before you go, the old oil will shoot bad fumes which won't burn in your intake.

Let me know how it goes.

 

so i took my truck to a good friend who is a mechanic and im getting this worked out
i will let you guys know what the outcome is

o and thanks to everyone who gave their wisdom!

 

fail .... you're gonna spend tons of money and still not pass.

Happens all the time and I hate to see it happen.

I hope it works out for you.

 

I'm going through the same issue right now. Failed twice due to high NO. I emoved the EGR valve and the EGR return pipe. The EGR return pipe was caked with black gunk. I cleaned that and flushed out the EGR valve with cleaner. I will go retest tomorrow. But I've noticed the car is running a lot smoother since then. I reset the CEL light and it has not turned back on after about 45 miles. I think I'm going to throw in the denatured alcohol before I hit the testing center.

 

put a gal of denatured alcohol in your tank with 1 gal reg gas asn pass with flying colors and fix your truck when you want and dont let your local government have you by the balls


IT WORKS

 

If you passed CO and HC but failed NOx, the problem is almost certainly in the direction of the EGR system. Burnt valves, broken PCV grommets, and an open vacuum vent can cause all sorts of problems, but I would be surprised if they cause ONLY NOx problems.

Before I started thinking of replacing the heads, this is where I'd look. The whole point of the EGR system is to inject exhaust into the plenum ("upper intake manifold") through a foot-long tube into the middle of the plenum. While I never had your NOx problem, during a head-gasket job I discovered that tube so covered in "gunk" that I almost couldn't pull it out. The inside of the plenum was also a mess. If that tube is completely blocked, then your EGR system isn't doing anything and you would be almost guaranteed to fail.

Cleaning the plenum is no picnic, but it's just plain work with paint thinner and a bottle brush; no expensive head job.

Good luck.

 

Our van fail the NOx for like the 3rd try. Due to some crook who took the oem cat. convertor. So we replace it with a smaller one than the oem. We took it to smog it and still fail. So last effort to it. We bought another cat. convertor, about $200.00 one, is smaller but bigger in size and put that sucker in with the old cat. convertor is at, well before the old one, and pass the smog in our first try... Now the van is running on 2 cats. convertor... It is similiar to the newer Tacoma style that I have seen. You can either try that. Also for your oil. Use STP Oil treatment. the no burn oil. 3 qts of regular oil and two bottle of those STP, and when ever you pass it. Change your oil...

|===[Smaller Cat]===[Bigger Cat]====[ muffler ]=====[ smaller muffler ]===| <----- how the van is currently at...