1993 Nissan 240SX 93 Nissan 240SX smog check help

Tiny
SUPRA33202
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  • 1993 NISSAN 240SX
Engine Mechanical problem
1993 Nissan 240SX 4 cyl Two Wheel Drive Manual 24K miles

I have a 1993 S13 Hatchback with 24K miles.

The previous owner failed the smog check yesterday.

The result:

M1. 15MPH
HC: MAX 88 AVE 21 MEAS 28
CO(%): MAX 0.52 AVE 0.06 MEAS 0.08
NO(PPM): MAX 704 AVE 150 MEAS 775

M1. 25MPH
HC: MAX 53 AVE 13 MEAS 24
CO(%): MAX 0.50 AVE 0.05 MEAS 0.13
NO(PPM): MAX 738 AVE 136 MEAS 507

My friend help me to do the regular maintenance services after I brought the car.

We did:

Change engine oil and oil filter
Flush coolant and fill in 50/50 coolant
Clean fuel and change fuel filter
Replace air filter
fill up 91 Octane

I just smogged the car today and it failed.

M1. 15MPH
HC: MAX 88 AVE 21 MEAS 41
CO(%): MAX 0.52 AVE 0.06 MEAS 0.12
NO(PPM): MAX 704 AVE 150 MEAS 784

M1. 25MPH
HC: MAX 53 AVE 13 MEAS 31
CO(%): MAX 0.50 AVE 0.05 MEAS 0.10
NO(PPM): MAX 738 AVE 136 MEAS 432

How do I pass the NO(PPM) with 15mph? Any suggestion? Replace O2 sensor, catalytic converter?

Thanks!
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Thursday, April 10th, 2008 AT 1:52 PM

4 Replies

Tiny
RASMATAZ
  • MEMBER
Try the EGR valve open and inspect for carbon and make sure its getting vacuum at the correct time-its job is to control the oxides of nitrogen by lowering the combustion chamber temperature.
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Friday, April 11th, 2008 AT 12:30 PM
Tiny
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THis is what we did last night:

1) We tried to remove the EGR valve entirely, but we don't know exactly how. Basically, we just removed the EGR valve vacuum hose and spray some Pryroil Carb&Choke Cleaner in it. We also sticked out finger in the bottom of the EGR valve and lift up the diaphragm while the engine is running. The engine stumbled, so we believe the EGR valve is working. Is there a easy way to remove the EGR valve from the car entirely? I want to clean the inside parts of the EGR valve. What nuts do I have to remove first? And what other parts do I have to remove first?

2) Then we seafoamed the car. We followed his steps:

33% gas tank, 33% crankcase. 33% intake manifold through brake booster line. I have a question here. Why the brake booster line will connect to the intake manifold? What is the purpose? And why there are other vacuum lines connect to the intake manifold?

Compare with other cars on youtube, my car doesn't have alot of smog coming out from the exhaust. Do we need to pour one more bottle of Seaform? If we decided to pour 1/2 bottle to intake manifold and 1/2 bottle to gas tank, do we have to do oil change and change the oil filter again? My friend said we don't have to change the oil and oil filter, but I argued that the seafoam will make the engine oil thinning. So, changing the oil and oil filter is needed after each seafoam regardless where we pour into.

That is all we did.

3) "ok, do this, add a bottle of isopropyl alcohol to about a half filled gas tank, drive it around a bit to get it mixed and in the fuel line. Alcohol lowers combustion temperatures thus NOx levels will be lower. Also, nox resolved from running lean which is one of the symptoms. Get the highest percent isopropyl alcohol and try again, get around 90% because the other 10 percent is water, though water is not combustable, it will dilute enough to not cause any harm. Also, try retarding your timing a few degrees. That may help. These are just cheap/money free possibilities. The alcohol wont hurt your engine, just dont use more than 1 bottle. About 16 ounces

Let me know if this works for you. I bet it will. Pm me or something"

Do you thing pouring alcohol in the gas tank will help emission?

Thanks!
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Saturday, April 12th, 2008 AT 1:45 PM
Tiny
RASMATAZ
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Do you thing pouring alcohol in the gas tank will help emission? No its not gonna help-Nox is formed when the combustion chamber exceeds over 2500F deg. The EGR reduces the temperature by diluting the A/F mix-Might want to check the cooling system out.

Does the engine pings/knocks during acceleration?
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Saturday, April 12th, 2008 AT 4:08 PM
Tiny
SUPRA33202
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1) Will high octane gas and octane booster help emission in my case?

2) Will retard ignition time help emission? How does it work? And how do I adjust the timing?

Thanks!
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Monday, April 14th, 2008 AT 1:38 AM

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