FAILED CALI SMOG... Need Help

[xka24detx]

Okay my 91 240 just failed california smog. It passes everything but NOX... The Maximum Allowable Emmisions at 15mph is 799 and 25mph 738 and the Gross Polluter Limits is 2002 at 15mph and 1802 at 25mph. The car is putting out 4964ppm at 15mph and 4952ppm at 25mph... The guy said it might be a bad EGR or CAT... Anybody have any ideas to help me out? Cause i dont want to spend alot of $ having a shop check it out when it might be something simple i could fix...

Thanks

[S14DB]

I betting EGR. Check the vac lines to it first. Then check the vavle.

[xka24detx]

This is a newb question... but where is the EGR valve? I grew up with toyota's all my life so im not yet aquainted with Nissans yet. :)

[sLip techniques]

behind your intake manifold right near the firewall, and to check if your egr works get your finger and push under it to see if it bogs, if it does bog then it works. Since it appears you just bought the car i would take out the cat to see if melted or not.

[xka24detx]

okay i found the EGR valve... but i dont get what you mean by push it in? If someone could take a pic and show me what to push? Thanks

[SauN]

also check the small hoses around the EGR valves as well. Some of them go through some wierd bends causing the hoses to crack and tear at those bends.

[Var]

there is more than just one problem..5000 nox is really unusual . Could be a combinations of timing, carbon buildup, cat and egr. Maybe dirty fuel filter. Post up the rest of the numbers

HC, CO, CO2, O2, and rpm's

[xka24detx]

there is more than just one problem..5000 nox is really unusual . Could be a combinations of timing, carbon buildup, cat and egr. Maybe dirty fuel filter. Post up the rest of the numbers

HC, CO, CO2, O2, and rpm's

I was already planning on running seafoam through the engine, changing oil, new plugs, etc... but i dont think that would have made that big of a difference. Thanks... Here is the results...
http://img.photobucket.com/albums/v510/pinoyricer103/smog2.jpg

[HyperTek]

run Seafoam!!!!

I had same problem. Pleease dont PM me about how.. its been discussed. But I also thru on a new cat when I retested...

[drew935]

It's not the cat. Yea run the seafoam. Do a search for it. Looks like you have a problem with the charcoal canister, pvc valve, and maybe the egr. But it is a problem that I have on my civic as well. It barely passed the nox reading. Also read up on the FSM to get better acquainted with your 240.
FSMs (http://www.zeroyon.com/index/content/view/24/47/)

[Ritz S14]

I say start with checking the EGR(yes toyotas have them too), and if you haven't already, replace the Oxygen sensor.

Things you need to verify..
Was the car warmed up? How old is the cat? Air injection working?

The early 90s tend to fail right out of the factory, which is why they probably stopped using the "91" cams.

[drew935]

That's right. I forgot that we have a smog tech on the boards. :duh: What's your name? I have some friends that need a smog... :2f2f:

[racer98]

Okay my 91 240 just failed california smog. It passes everything but NOX... The Maximum Allowable Emmisions at 15mph is 799 and 25mph 738 and the Gross Polluter Limits is 2002 at 15mph and 1802 at 25mph. The car is putting out 4964ppm at 15mph and 4952ppm at 25mph... The guy said it might be a bad EGR or CAT... Anybody have any ideas to help me out? Cause i dont want to spend alot of $ having a shop check it out when it might be something simple i could fix...

Thanks



OK here are a couple of things you need too do.


1) replace the CAT
2) when you go in for smog make sure the fuel load in your car is about
quater of a tank.
3) inflate the tires as much as possibile for the tire you have on the rear.

then tell us the results.

[007jpang]

sea foam that shit

john

[s13gonwild]

1.Replace CAT
2.when you go in for smog make sure the fuel load in your car is about
quater of a tank.
3. inflate the tires as much as possibile for the tire you have on the rear.
Also drive/leave car on as long as you can then smog it.

[infinitexsound]

haha v is the greatest.........pitching sales..

[idlafie]

1.Replace CAT
Better to remove it from the exhaust manifold, visually inspect the insides & see if it's still good. If the honeycomb catalyst inside the cat is missing or melted then you'll have to replace it. If the honeycomb is still intact, then just bolt it back up & continue to use it.


2.when you go in for smog make sure the fuel load in your car is about
quater of a tank.
HUH?? How is a quarter tank of gas gonna affect your smog test?


3. inflate the tires as much as possibile for the tire you have on the rear.

HUH?? you're gonna have to explain this one!!


Also drive/leave car on as long as you can then smog it.
Yep...by leaving the engine running you are heating up the catalytic converter so it can due its job - to filter as much of the noxious gases produced by the internal combustion engine as much as possible before venting it to the atmosphere/air we breathe.

The purpose of your EGR system is to reduce oxides of nitrogen pollution which causes smog. Oxides of nitrogen are produced when combustion temperatures are high. By allowing some of the exhaust gas (mostly carbon dioxide and water vapor) to be recirculated back into the engine, the inert exhaust gas cools the combustion process by taking up space in the combustion chamber and making combustion less efficient - kinda like pouring water on a roaring HOT fire so as to keep the fire under control & keeping the fire in check.

You might want to click on the attached link & read the postings I listed.
http://www.zilvia.net/f/showthread.php?t=65792

These links can also help:
http://www.valvoline.com/carcare/articleviewer.asp?pg=ccr20040501e1&cccid=2&scccid=1
http://www.valvoline.com/carcare/articleviewer.asp?pg=ccr20040501e2&cccid=2&scccid=1

You'll find the information helpful.
ID
'95 SE

[Buffalo Daughter]

Somethings i might suggest -

Before wanting to replace the cat, make sure that that is actually the problem. Although People always say to its the cat you should know that it is actually damaged or no longer working. You can test it by using a pyrometer or shake the cat and hear if it rattles. A catalytic converter is suppose to last the lifetime of the vehicle unless you have detenonation that causes it to melt the cat.

NoX - Anything that increases temperature will cause high NoX. Probs with the cooling system, heated air intakee, or compression raised by carbon deposits can cause Nox to increase. Ignitition Timing also affects this. CHECK YOUR SPARK AND TIMING. Maybe your spark plugs are fouled up and/or your cap and rotor need to be replaced.

EGR - like the said above you need to check this bad boy out to. From what i know its most likely your egr. Test it or get it tested because the EGR is one of the most important things if not the thing that helps keep NoX low. Check if the valve is still functioning. CHECK THE EGR MOST IMPORTANTLY.

[drew935]

I'm curious as to which part is actually causing all that Nox,.. :smash:

[Var]

1-inflating your tires will cause a little bit less load on the car therefore reducing emissions. Because the numbers are so high, that's irrelevant in this case

2-Having less gas i supposed would also put less load on the rear end during the smog..?

3- Leaving the car on helps in a sense, but before it's run it should be heated up again with a fast idle. Some smog guys wont do this for you cause you're technically not supposed tol.

[Ritz S14]

Yeah..but whatever. I do it all the time :)

[Pacman]

I had this same problem with my '91. Definitely do some work with your EGR. Take it off and clean the hole thats on the intake manifold. Clean the EGR whole so it'll work correctly. Look at all those hoses, especially with the bottom hose thats on the EGR that one is always rotted. After you do that, take it again to get it pre-tested. If the ratings go down significantly, go ahead and look at the Cat. Replace that AFTER you do the other things.

This same stuff happened to me so I talk from first hand expirence (also having fuel control problems). I had to go to the smog only like you're going to have to do. Good luck, and remember, PRE-TEST WILL SAVE YOU!!!