Smog help!! 93 240sx stock - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

darkslide92 · 08-25-2011, 09:22 AM

Okay so I know there's a bunch of posts about this already, but most are pretty old, and maybe someone might have other ideas than I've read.*
The car: it's an all stock 1993 240sx. Has new egr and timing was adjusted back to stock (was previously retarded to help lower NO's). Exhaust is fully stock except for the fact that previous owner put two cats on the car to help pass. But i later found out it doesn't help so I'm planning on changing out to a stock downpipe.
Readings: smog tech said they were very strange lol. Measured HC at 10ppm for 15mph and 4ppm at 25mph (avg is 43@15mph & 26@25mph). CO's were both measured at 0%
Now the fun one. NO ppm max: 493@ 15mph & 516@ 25mph. Avg is in the mid to high 100's. But mine measured 1550 at 15mph and 171 at 25mph.
Thanks in advance for any help and ideas

Edwin562 · 08-25-2011, 09:34 AM

Car running hot??? you heating problems??? or either smog tech's machine is dumb... lol

is CEL on???

Edwin562 · 08-25-2011, 09:46 AM

try this link, there is a lot of good info on this...

High NOx Readings and What Are the Causes!

darkslide92 · 08-25-2011, 03:15 PM

Thanks for the link. The only problem is I don't have a five gas analyzer to work with. And the car runs fine, no heating problems whatsoever, never ran hot even when drive it hard. And what is CEL?

Edwin562 · 08-25-2011, 03:29 PM

CEL= Check engine light

darkslide92 · 08-25-2011, 04:04 PM

Oh, no it's not on. Nothing seems mechanically wrong

08-25-2011, 09:22 AM	#1
darkslide92 Leaky Injector Join Date: Jun 2011 Location: San Jose Age: 31 Posts: 63 Trader Rating: (0) Feedback Score: 0 reviews	Smog help!! 93 240sx stock Okay so I know there's a bunch of posts about this already, but most are pretty old, and maybe someone might have other ideas than I've read.* The car: it's an all stock 1993 240sx. Has new egr and timing was adjusted back to stock (was previously retarded to help lower NO's). Exhaust is fully stock except for the fact that previous owner put two cats on the car to help pass. But i later found out it doesn't help so I'm planning on changing out to a stock downpipe. Readings: smog tech said they were very strange lol. Measured HC at 10ppm for 15mph and 4ppm at 25mph (avg is 43@15mph & 26@25mph). CO's were both measured at 0% Now the fun one. NO ppm max: 493@ 15mph & 516@ 25mph. Avg is in the mid to high 100's. But mine measured 1550 at 15mph and 171 at 25mph. Thanks in advance for any help and ideas

08-25-2011, 09:34 AM	#2
Edwin562 Post Whore! Join Date: Nov 2009 Location: Whittier (562) Age: 34 Posts: 4,721 Trader Rating: (35) Feedback Score: 35 reviews	Car running hot??? you heating problems??? or either smog tech's machine is dumb... lol is CEL on???

08-25-2011, 09:46 AM	#3
Edwin562 Post Whore! Join Date: Nov 2009 Location: Whittier (562) Age: 34 Posts: 4,721 Trader Rating: (35) Feedback Score: 35 reviews	try this link, there is a lot of good info on this... High NOx Readings and What Are the Causes!

08-25-2011, 03:15 PM	#4
darkslide92 Leaky Injector Join Date: Jun 2011 Location: San Jose Age: 31 Posts: 63 Trader Rating: (0) Feedback Score: 0 reviews	Thanks for the link. The only problem is I don't have a five gas analyzer to work with. And the car runs fine, no heating problems whatsoever, never ran hot even when drive it hard. And what is CEL?

08-25-2011, 03:29 PM	#5
Edwin562 Post Whore! Join Date: Nov 2009 Location: Whittier (562) Age: 34 Posts: 4,721 Trader Rating: (35) Feedback Score: 35 reviews	CEL= Check engine light

08-25-2011, 04:04 PM	#6
darkslide92 Leaky Injector Join Date: Jun 2011 Location: San Jose Age: 31 Posts: 63 Trader Rating: (0) Feedback Score: 0 reviews	Oh, no it's not on. Nothing seems mechanically wrong