Smog Problem, Cali, 91 240sx

[Drift Motion]

I got a 91 S13 with 95 KA(OBD-I most likely non cali spec, 68K)#29 ECU(Auto, Non-Cali Spec as well) Car is manual thoWalbro Fuel Pump(not sure if that matters)New Fuel Filter about a year agoSpark Plugs(pretty new)Wires(replaced the same time as fuel filter)2.5 inch catbackCAT dont look to be the original OEM unit, it looks to be a universal one thats welded to the OEM flange on one side, cat back on the otherO2 Sensor(put in about 2 weeks ago, but there is a slight burn on the wiring no wire exposed)

Failed smog on Fridayboth 15mph and 25mph reading is way high, max allow is 700ish, my reading were about 3000+I did drive the car for about 1 hour on the freeway to the smog place, but I did have to wait about 15-20mins....i kept the car idling tho

HC (Meas/Max) 45/118 50/93CO 0.00/0.75 0.00/0.63NO 3300/799 3257/738____^15mph___^25mph

My timing was off, so I fixed that after I got homeFuel Cap didnt pass either, fixed as well

from some research, I tried to clean out the emission system by spraying carb cleaner through a vacuume into the TB, some blue smoke came out in the beginning but nothing too noticeable afterwards

ive used a bottle of Guarantee to Pass, fixed couple more things, i went back to do a pre test, the numbers actually went up....

then i cleaned out the EGR tube, cleaned the MAF, sea foamed the engine(not much white smoke came out), replaced that lil hose thats under the BPT, connects to the EGR valve(the hose wasnt bad, but i replaced it anyway) and fixed this big exhaust leak i have right before the cat

i tried to do the test of lifting the EGR valve, it does not affect the engine one bit, no stumble, or anything

so the mechanic said i should take the bottom part of the intake manifold off, to clean more of the carbon build up....should i?or pay n go try the pre-test again?

the cat has been through 2 sea foam....if that makes any difference

[hwyix]

Failed smog on Fridayboth 15mph and 25mph reading is way high, max allow is 700ish, my reading were about 3000+I did drive the car for about 1 hour on the freeway to the smog place, but I did have to wait about 15-20mins....i kept the car idling tho

HC (Meas/Max) 45/118 50/93CO 0.00/0.75 0.00/0.63NO 3300/799 3257/738____^15mph___^25mph

My timing was off, so I fixed that after I got home

then i cleaned out the EGR tube, cleaned the MAF, sea foamed the engine(not much white smoke came out), replaced that lil hose thats under the BPT, connects to the EGR valve(the hose wasnt bad, but i replaced it anyway) and fixed this big exhaust leak i have right before the cat

i tried to do the test of lifting the EGR valve, it does not affect the engine one bit, no stumble, or anything

the cat has been through 2 sea foam....if that makes any difference

What are the other number ( o2 & co2 )?

Wrong timing will cause High NOX. Looks like you fixed that.

After market cat for the most part are junk. I never recommend aftermarket cats to my customers. Of course they almost never want to buy OEM.

Sounds like from your test the egr is not working. EGR is very important lower the NOX.

What is the temperature of your car when running the test?

[Drift Motion]

should i try another EGR unit?

the car is fully warmed up before the test...so yeah

for 300 bucks for a OEM cat...i'd rather just pay someone for the SMOG...LOL

i heard the aftermarket cat lasts u like 2 SMOG test, and its done...

CO2 is 13.9/14.2O2 1.0/0.7

i remember the second time i went back for smog, my CO2 reading went up to 15-16%

[hwyix]

Replacing the EGR would be a great start. Then redo your egr test.

I would agree that most aftermarket cats are good for 1 or 2 years. So maybe one or two smog test.

[zer0c123]

How did you clean the EGR tube? There's actually a few parts to the EGR system. 1. EGR2. EGR-BPT3. BPT-tube4. EGR pipe (long pipe that runs from side of the engine bay to the other)5. I don't remember the name this one. Has like 3 bolts and one of which is a pain to get to without a swivel socket.

You can also try checking the L-shaped rubber hose to see if there is any holes. Replace it with one from the dealer and do the push-up test again. If it works, then you would have avoided doing maintenance on the egr parts, which is a PITA to work on .

[Drift Motion]

i took out the EGR pipe, along with the valvei think i know the 3 bolt thing ur talkin about, its in between the intake manifold right. i was able to get that off

the L shaped hose did not have any holes on it, but i replaced it anyway

im guessing it has something to do with the BPT thing thats right next to the EGR vavle

[zer0c123]

You can try to do a vacuum test on the egr value, egr-bpt valve and the bpt pipe. I remember those three have small diameter pipes, so it would be easily all carbed after so many years.