High HC at 15 MPH? 240sx S13 Emissions Test

[nakaathony]

The dreaded California emissions test strikes yet again....

So i bought my S13 back in (2015) and it was registered and said to "pass smog", so I went to smog it for change of ownerships and what not and then it got "Gross polluter". I drove it like that for a year because the registration was still current at the time. I failed emission all across the board from HC,CO, and NOx in (2016). I knew that the catalytic converter was one of the main causes because it probably hasn't been replaced since the dinosaur ages.

Anyways, I finally went to smog it again (01/15/17) with my free retest before I went back up to college. I knew it wasn't going to pass, but I need a moving permit from the DMV to take my car with me to college to fix it. Before going back in to smog, I seafoamed it, then replaced the sparkplugs, sparkplug wires, O2 sensor, fuel filter, oil filter, air filter, did and oil change, been running 91 gas ever since. These caused my emission number to drop alot! But I still didn't pass ( I knew I wasn't going to pass because I had yet to replace my catalytic converter).

Finally, Im back in school and I get the Catalytic Converter installed from a local shop (great shop!). So yesterday (02/12/17) I take my car to get smogged at a shop in Milpitas. My numbers were great, but I STILL DIDNT PASS...:ugh:
So I passed everything in the functional and visual, But for emissions, I failed only the HC at 15mph (Passed at 25mph). I passed everything else and the Cat is doing its job with the NOx and the CO, but what is causing my HC to be twice as high at 15mph?! Keep in mined, everything else is practically new that I changed.

Also, I noticed every time I drive long distances, I notice two spots of oil or some type of liquid on top of my intake (pictures), I don't know where it comes from? and I don't know if oil is shooting form the crankcase or something? Could that be the cause of the high HC because of unburned fuel?

The pictures below show my emission numbers from Gross Polluter to an almost Pass and the oil spot in the engine bay, if you could check those out that would be great!

I've been doing research but I still don't know what it could be ? maybe the timing, unburned fuel, leaks, compression, clogs, ahh, Any Suggestions?
:confused:

[nakaathony]

bump, does anyone know what it could be ?

[andisan]

I always say that black box next to the header

Take that off and clean it really good

That gave me headaches and I ended up buying a new one instead of cleaning it, it was full of carbon and I could of just cleaned it

But at the time is was like F it

Try that

[slider2828]

Stuff dropping from intake is probably water.... Check your coolant hoses....

Also you made sure to drive the car around before testing right? Don't test on cold engine and parts.....

Clean out all the emissions stuff like andisan said...

[silviaks2nr]

Your motor probably needs valve stem seals. Not a huge job and you can do it with the head on.

[nakaathony]

I always say that black box next to the header

Take that off and clean it really good

That gave me headaches and I ended up buying a new one instead of cleaning it, it was full of carbon and I could of just cleaned it

But at the time is was like F it

Try that

By the black box do you mean the AIV(Air Intake Valve) that connects to the intake?

[nakaathony]

Stuff dropping from intake is probably water.... Check your coolant hoses....

Also you made sure to drive the car around before testing right? Don't test on cold engine and parts.....

Clean out all the emissions stuff like andisan said...

Yea I drove the car before I took it in, drove it for a good while 30+ mins. and i'm running 91 gas (Usually shell or something), also the last 3 smogs I got for the HC in order were from 157, 137, and then 138 with a max of 68 ppm. The cats are working great (smog guy said), theres just another problem. Ill clean out the black box before taking it back

And theres stuff that always comes onto the intake, like two circles on different sides (picture), I don't know what it is? It's not dripping from the intake, but onto the top of the intake?

[nakaathony]

Stuff dropping from intake is probably water.... Check your coolant hoses....

Also you made sure to drive the car around before testing right? Don't test on cold engine and parts.....

Clean out all the emissions stuff like andisan said...

Yea I drove the car before taking it in and I put 91 gas in it(Usually shell), the smog guy said the cat is working fine, but theres another problem. But ill be cleaning out that black box and probably some other emissions stuff before taking it back. My numbers for HC for the last three smogs at 15mph in order were 157, 137, then 138 with a max of 68.

Also, there is stuff dripping onto the intake, not dripping from it. I don't know what it could be ? maybe it is water?

[Smurf_240SX]

Did the technician warm up the cat before doing the test? Warm it up @2500RPM for about a min or 2 before you test it.

Also I'd say advancing your timing on distributor +2 degrees (you'll still be within specs) will bring your HCs down.

[andisan]

By the black box do you mean the AIV(Air Intake Valve) that connects to the intake?




I looked it up and it's the "PAIR VALVE"
98023

[nakaathony]

Stuff dropping from intake is probably water.... Check your coolant hoses....

Also you made sure to drive the car around before testing right? Don't test on cold engine and parts.....

Clean out all the emissions stuff like andisan said...

I looked it up and it's the "PAIR VALVE"
98023

alright! thanks so much for searching it up and double checking ! I will be cleaning that up soon

[nakaathony]

Did the technician warm up the cat before doing the test? Warm it up @2500RPM for about a min or 2 before you test it.

Also I'd say advancing your timing on distributor +2 degrees (you'll still be within specs) will bring your HCs down.

Yea it was warm when I got there and he warmed it up before testing, But timing is something that I will look at. I might just rent a timing gun from Autozone to check the timing to see if the previous owner messed with it or not.

[nakaathony]

Okay! sorry for the late update (college) so something came in mind, I replaced my o2 sensor again and this time the HC numbers went even high and faild at both 15 mph and 25 mph, could it have something to do with my fuel injectors? me and my dad checked the voltage in my injectors and they all seem pretty fine! all in all, the main point is that my car isn't burning fuel correctly?
p.s. I found this on a smog article online, and I think this is most likely what is happening in my engine? any suggestions?

Lean Fuel Mixture - Any condition which will cause unmetered air to enter the intake manifold, and ultimately the combustion chambers, will cause high hydrocarbons (HC). This condition is called a lean miss-fire. Such faults as vacuum leaks and gasket leaks will cause lean fuel/air mixtures. Broken, disconnected or misrouted vacuum hoses will do the same. It is also important to note that many engine components rely on engine vacuum for proper operation. If any of these components are defective, externally or internally, they may cause large vacuum leaks as well. A good example of such a component is your vehicle's power brake booster.

[1on1]

Try this as this helped out a lot of people back in the day.

http://zilvia.net/f/showthread.php?t=372184&page=2

Post #58. The original post no longer has photos of where to clean but there's a lot of information about failed smog.