SR20 Forum banner

Emissions, help please

659 Views 10 Replies 6 Participants Last post by  N13 Freak
Emissions, help please - Down with the NOx

Ok, I ran through emissions today, and really it's not totally accurate because I didn't run it long enough before going in (only about a 15 minute warm up, half city, half freeway). I do seem to be running a bit on the rich side though and I think that's a big part of the problem, wondering how to fix this. BTW, I'm running a Walbro 255lph, no FPR yet.

Here's the results:

In case the picture is hard to see...

Target: THC 1.20 - NOx 3.00 - CO 30.0

Result: THC 3.47 - NOx 5.70 - CO 11.4
Failed on visible emisions as well, but that's because the car wasn't totally warmed like I said and as soon as I got back to work 15 minutes later, no smoke. The smoke was slightly blue though, thinking maybe some oil blow-by maybe?

Anyway, get back at me.

See less See more
1 - 11 of 11 Posts
fpr will take care of the running rich problem. the walbro ups the fuel pressure about 2-3 psi. as far as tring to pass nox without egr i dont thing anyone has someone correct me if im wrong.
I hope someone's passed NOx, 'cause otherwise I'm in trouble. I'm assuming there's not really any way to outfit this motor with an egr setup without investing a significant amount of money/time...?

BTW, someone told me, and it scares the crap out of me to even think about doing this, but a pint of 91% alcohol to a tank of gas? Someone correct me if I'm wrong, but I think this would cause more problems than good.

I've used denatured alcohol in my car to pass emission a few months ago. I ran the car till it was almost empty, put in 4 gallons of premium gas and an entire gallon of denatured alcohol I bought at Home Depot. It made a drastic reduction in emmisions and needless to say I passed with flying colors. By the way I failed pretty badly before I did this. I rarely drive the car on the streets so I didn't feel bad about doing this. I did not boost at all when the alcohol was in the tank. After the test I filled the tank with more premium gas and took it easy till that tank was gone. That's my .02 cents.

Since your CO is not too high, you are not running very rich...high HC's could be from incomplete combustion--timing/ignition problems. High NOX is from a lean condition, or a very hot engine. A catalytic converter can sometimes go bad by not treating nox, but still do ok with HC and CO. I'd try the alcohol thing--although I'm not sure if it will affect HC's if there is another problem contributing other than mixture, but it will definitely lower cylinder temps and therefore lower nox. My fingers are tired from typing, bye!
Ok, I'm going to try a couple things...

*I'm going to run the car a lot longer before testing again, at least 30 minutes to 45 minutes.
*Check the timing-What would everyone reccommend as far as how much these can be retarded or advanced safely and what's everyone running as their standard setting with a JWT ecu?
*Switch to an SE-R o2 sensor since I'm still running the 300zx o2, and the JWT is supposed to use the SE-R sensor to my knowledge.

Last would be to try the alcohol thing, but still, that seems overly risky...

Someone correct me if I'm wrong but I think the 300ZX and the SE-R O2's are the same aren't they?
Shouldn't be considering this one's in the turbo elbow and didn't need an adapter, the SE-R should be of a larger diameter if I'm not mistaken. I'm going to check the voltage on lunch though, see what the o2 sensor in there is putting out...

Reason 9468 why i love Florida :D

No useful info from me as we do not have emmissions testing in the sunshine state.
Ok, you suck... ;)

Damn whatever boneheads in California and Oregon came up with these BS tests. Friggin' treehuggers.
BTW, I finally got around to hooking up my tach. Reading 1340-1350rpms at idle. Didn't get a chance to look at my TPS sensor, once I make sure the voltage is right, I'll play with the IACV until I'm idling around 850rpms...

1 - 11 of 11 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.