Alright, first off, I'm probably just paranoid and my car will probably be fine, but is there anything I can do to my car, that'll help me pass inspection. My biggest fear is with the sniffer test, everything else should be just fine. So if you Jersey or California people have any tips/advice for me, I'd greatly appreciate it. Thanks in advance.

 

alright, well i failed today. one of my rear brakes failed, but i know how to fix that one. but i failed emissions too. i had a nox reading of 1187 (879 is passing), my hc level was 65 (117 passing), and co was .17 (.65 passing). so i've been doing some reading and found most of the time it's a vacuum leak or a bad egr that causes the nox to be high, correct? i looked and don't see any hoses detached, so i checked the egr. i can push the plunger thing inside up and down, doesn't that mean it's good still? my original thought was it was my o2 sensor, because it's currently heald in by jb weld and copper rtv silicone, but i don't hear a leak comming from there either. any advice? thanks.

 

If it was your O2 sensor, your HC and/or CO would have been high.

EGR valves are known for plugging up with carbon. Often times it's the passages in the intake manifold rather than the valve itself that are plugged.

Timing adanced too far can also cause high NOx, as can carbon build-up in the chambers.

Most likely it's the EGR valve or the EGR passages.

 

alright, what would you suggest would be the best way for cleaning out the passages?

 

Remove the valve first and see what it and the passages just under it look like. If plugged, open them up.

However, the only real way to get the intake passages clean is to remove the manifold and dig the crud out of there.

 

thanks alot. unfotunately you gave me the answer i was afraid to hear; remove the manifold to clean it. i was hoping for some magical solution like spray in carb cleaner or something.

 

just out of curiosity as a band-aid fix just to pass emissions couldn't retarding the timing a few degrees help out also since he does have a little room to play with as far as co and hc?

 

as five7 said, timing can cause high NOX, so make sure the timing is right.

to check to see if the EGR passages are clogged, you can do this with the motor cold, start the motor up & lift up on the same place you said you did before. if the motor starts to run bad or dies when you lift up on the valve the passage are open enough to work & you have a bad valve, bad solenoid, vacuum problems or problems with the ECM.
if you do get a change in the way the motor runs, check the valve to see if it works, to check the valve, find a small vacuum hose with good vacuum on it with the motor at idle & hook it up directly to the valve, if the motor changes like it did when you manually lifted up on the valve then the valve is ok.

when you manually lifted up on the valve, if there was little to no change then you have clogged passages.
the EGR valve seldom locks up, it is normal to be able to lift up the valve & the valve be bad.

if the passages are clogged this works for me most of the time.
with a variable drill use a section of an old speedometer cable, the inside piece, not the housing, remove the EGR valve & get a hole started into the carbon using a punch or screw driver, next put about a 3~4 inch piece of the old speed cable into the drill & run it into the passages, use a longer piece as you get far into
the passages. spraying some carb cleaner on the carbon as you go helps too.


rx7speed. if there is problems with the EGR, timing alone probably won't do enough, if he was closer, say around 100 then
then it would probably work. i don't know about NJ, they may check timing as part of the test there.