I badly need some help passing Ga smog test!

targa7088 · 11-12-2011, 06:36 PM

I have an 88 N/A 5spd, and I cannot pass the smog test to save my life! So far I've done a complete tune up, the converter is new, EGR valve works, Timing is dead on, and I only use 93 octane gas. My last readings are as follows:

readings allowed

HC 364H-376L 140H-144L

CO 2.76H-3.34L 0.89H-0.81L

NoX 501H-564L 984H-1077L

the H's are for the high speed(25mph) portion, and the L's are low speed(15mph) test. any help would be greatly appreciated, I'm baffled right now! can anyone help me!!

Awyman18 · 11-12-2011, 09:14 PM

well....believe it or not, ur catalytic converters are probably bad..lol ur car is old, so they most likely are old and poopy inside. Check ur cats, go under ur car, and see if u can kinda smack them around lol if u here any chinging inside, or any sort of sound...like almost dirt moving around. Most likely ur cat is bad, so its not working properly, which inturn means u will not pass smog test.

targa7088 · 11-12-2011, 09:58 PM

the converter is 3 months old. it was hollow when i bought the car, so i replaced it.

Awyman18 · 11-12-2011, 10:33 PM

which cat? theres one on the downpipe, which go bad pretty quickly, and then the one that would be ur cat back? if one of them was hollowed out, the 2nd one was probably hollowed out too

Sonyps307 · 11-12-2011, 11:54 PM

The NA's only have one cat and the turbos have 2 cats. Unless the car is from cali then it would have 2 cats. I think the vsv under the intake has something to do with smog. But Im not sure.

targa7088 · 11-13-2011, 12:49 AM

hmm now we're getting somewhere, the car probably did have 2 cats on it, the one i replaced is in the middle of the system,not directly after the manifold,see, the car came from florida, where they did away with emissions over 20 years ago so you could imagine....... i bet another cat con would help it out, because this thing runs like a champ, has tons of power (for an N/A car), and like I've said in the first post, everything checks out, timing, tune up, sensors, freakin errrrything! I've done emissions, and emission repair before, so i'm pretty familliar with how everything works. It's just that i've never really had to mess with one of these cars, this is my first supra so these tips from yous guys are awsome! I've owned rotary cars, SR20cars, I could get around those pretty easily. Too bad this engine has electronic advance........ But any how, thanks again for the tips, if anyone has more tips....keep'em flowin I certainly do appreciate them. Thanks again fellas

targa7088 · 11-14-2011, 10:26 PM

This car definetly came with only one converter, I'm begining to wonder if the aftermarket unit I bought is too small? I mean, it does look a little smaller than what I'm used to seeing. With the numbers I posted, is it possible that it would benefit from having another one added? I can't wait till it's 25 years old so I could swap this motor out, I know the 7m is a good motor considering the issues, but I really want a JZ block in this thing soooo bad. Thoughts anyone?

cre · 11-15-2011, 02:47 AM

What is the timing set to? Needs to be set to 10?BTDC with the diagnostic jumper in place and NO error codes stored in the ECU.

That HC and CO is too high for just a weak cat. With the NOX so low I think you're more likely looking at an incomplete burn or too much fuel (the EGR is still a consideration if it's stuck open and cooling the chamber too much for a clean burn); Your ignition timing may be retarded (whether you're timing light agrees or not) or your exhaust cam may be advanced.

Replaced the air filter recently?

Additionally, banging on a cat only tells you if it's falling to pieces; They generally fail LONG before that happen. The catalyst gets glazed over and as such doesn't interact with the gases. Also, not that continued high HC emissions will cause this glazing and neuter your cat.

targa7088 · 11-16-2011, 01:47 AM

I checked the cat, definetley not falling to pieces, and thank the car gods, because its only a couple months old! I'm gonna check the base timing with the timing belt cover off and let you guys know how it goes.

cre · 11-16-2011, 10:51 PM

Run too rich and you can kill a cat in a couple weeks.

11-12-2011, 06:36 PM	#1
targa7088 Stock Join Date: Nov 2011 Location: north GA Posts: 9	I badly need some help passing Ga smog test! I have an 88 N/A 5spd, and I cannot pass the smog test to save my life! So far I've done a complete tune up, the converter is new, EGR valve works, Timing is dead on, and I only use 93 octane gas. My last readings are as follows: readings allowed HC 364H-376L 140H-144L CO 2.76H-3.34L 0.89H-0.81L NoX 501H-564L 984H-1077L the H's are for the high speed(25mph) portion, and the L's are low speed(15mph) test. any help would be greatly appreciated, I'm baffled right now! can anyone help me!!

11-13-2011, 12:49 AM	#6
targa7088 Stock Join Date: Nov 2011 Location: north GA Posts: 9	hmm now we're getting somewhere, the car probably did have 2 cats on it, the one i replaced is in the middle of the system,not directly after the manifold,see, the car came from florida, where they did away with emissions over 20 years ago so you could imagine....... i bet another cat con would help it out, because this thing runs like a champ, has tons of power (for an N/A car), and like I've said in the first post, everything checks out, timing, tune up, sensors, freakin errrrything! I've done emissions, and emission repair before, so i'm pretty familliar with how everything works. It's just that i've never really had to mess with one of these cars, this is my first supra so these tips from yous guys are awsome! I've owned rotary cars, SR20cars, I could get around those pretty easily. Too bad this engine has electronic advance........ But any how, thanks again for the tips, if anyone has more tips....keep'em flowin I certainly do appreciate them. Thanks again fellas Last edited by targa7088; 11-13-2011 at 01:50 AM.

11-15-2011, 02:47 AM	#8
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	What is the timing set to? Needs to be set to 10?BTDC with the diagnostic jumper in place and NO error codes stored in the ECU. That HC and CO is too high for just a weak cat. With the NOX so low I think you're more likely looking at an incomplete burn or too much fuel (the EGR is still a consideration if it's stuck open and cooling the chamber too much for a clean burn); Your ignition timing may be retarded (whether you're timing light agrees or not) or your exhaust cam may be advanced. Replaced the air filter recently? Additionally, banging on a cat only tells you if it's falling to pieces; They generally fail LONG before that happen. The catalyst gets glazed over and as such doesn't interact with the gases. Also, not that continued high HC emissions will cause this glazing and neuter your cat. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

11-16-2011, 10:51 PM	#10
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Run too rich and you can kill a cat in a couple weeks. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

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11-12-2011, 09:14 PM	#2
Awyman18 3" Exhaust Join Date: Apr 2011 Location: columbus Posts: 151	well....believe it or not, ur catalytic converters are probably bad..lol ur car is old, so they most likely are old and poopy inside. Check ur cats, go under ur car, and see if u can kinda smack them around lol if u here any chinging inside, or any sort of sound...like almost dirt moving around. Most likely ur cat is bad, so its not working properly, which inturn means u will not pass smog test.

11-12-2011, 09:58 PM	#3
targa7088 Stock Join Date: Nov 2011 Location: north GA Posts: 9	the converter is 3 months old. it was hollow when i bought the car, so i replaced it.

11-12-2011, 10:33 PM	#4
Awyman18 3" Exhaust Join Date: Apr 2011 Location: columbus Posts: 151	which cat? theres one on the downpipe, which go bad pretty quickly, and then the one that would be ur cat back? if one of them was hollowed out, the 2nd one was probably hollowed out too

11-12-2011, 11:54 PM	#5
Sonyps307 Lexus & 550's Join Date: May 2010 Location: Baltimore Posts: 526	The NA's only have one cat and the turbos have 2 cats. Unless the car is from cali then it would have 2 cats. I think the vsv under the intake has something to do with smog. But Im not sure.

11-14-2011, 10:26 PM	#7
targa7088 Stock Join Date: Nov 2011 Location: north GA Posts: 9	This car definetly came with only one converter, I'm begining to wonder if the aftermarket unit I bought is too small? I mean, it does look a little smaller than what I'm used to seeing. With the numbers I posted, is it possible that it would benefit from having another one added? I can't wait till it's 25 years old so I could swap this motor out, I know the 7m is a good motor considering the issues, but I really want a JZ block in this thing soooo bad. Thoughts anyone?

11-16-2011, 01:47 AM	#9
targa7088 Stock Join Date: Nov 2011 Location: north GA Posts: 9	I checked the cat, definetley not falling to pieces, and thank the car gods, because its only a couple months old! I'm gonna check the base timing with the timing belt cover off and let you guys know how it goes.