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Car failed CA smog...Need some help

nhra-trans-am

nhra-trans-am

New Member
I recently purchased an 89 TTA and I am trying to get it to pass CA smog. It failed due to the high NO level of the smog test.

The car was idleing a bit rough so I changed the spark plugs, pcv valve, fuel filter and serviced the fuel injection. However the idle is still rough. I was thinking that maybe the TPS sensor was to blame. Need some help figuring out what the problem is. TIA
 
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Here are the smog readings

15mph HC max 80 ave 33 meas 34
25mph HC max 62 ave 24 meas 28

15mph CO max .52 ave .08 meas .02
25mph CO max .42 ave .06 meas .03

15mph NO max 549 ave 165 meas 544
25mph NO max 507 ave 142 meas 1300
 
[QUOTE= It failed due to the high CO level of the smog test.

Maybe I'm reading it wrong, but according to your readings, it looks like you failed NOx on the high speed test, and about boarder line on the low speed test.
The CO's look like there in spec, I'm I reading that right? Are you using premium fuel? Does you car have the stock chip? High NOx can be caused by the following:
High Heat, Lean Mixtures, Advanced timing, EGR not working properly, cooling system problems, Excessive carbon build up in the combustion chamber, Hot spots in the combustion chamber & usually the #1 culprit, a defective Catalytic converter. Hope that helps
 
That is correct, I went ahead and edited it. It had a high NO level. I am using premium 91 fuel.
I just bought the car, but as far as I know it is bone stock, including the chip. It appears to have a new cat on it though.
 
Congratulations on getting your TTA!!! I would double check your chip, just to make sure its stock, its easy to do. When I bought mine, the owner said mine was stock too. Come too find out (couple months later) it had a ATR Pitbull race chip, go figure!

I would also check your fuel pressure, as running too lean can raise engine temp & cause major damage. Make sure your newer catalytic converter & EGR are in proper working order also.
 
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I highly recommend Turbo Tweak's emission chip. It cleaned up #14's emissions by a wide margin...and it's cheap; about $20.
 
nhra-trans-am said:
How would I check the chip?
Click to expand...

The computer is under the RF (passenger front) dash area, you'll have to
remove a couple trim items (very easy) & it pulls down. There will be a small rectangle looking access cover, remove that & the chip is inside. I'm not sure what the stock chip says on it, since mine did have one, might be a part number (mine said ATR pitbull) right on the chip.(if someone else can chim in here to confirm what a stock chip looks like or whats on it, that would be super, pictures are great)

Eric's Turbo Tweek chips are great, thats what I switched too also, but I would still confirm what you have as a starting point.
 
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Here is the chip that came in my tta, I just put turbo tweak classic chip in. What a difference, it idles better, it runs better, it runs cooler and turbo spools up faster. What a great chip.View attachment 1925
 
TURBO1 said:
The computer is under the RF (passenger front) dash area, you'll have to
remove a couple trim items (very easy) & it pulls down. There will be a small rectangle looking access cover, remove that & the chip is inside. I'm not sure what the stock chip says on it, since mine did have one, might be a part number (mine said ATR pitbull) right on the chip.(if someone else can chim in here to confirm what a stock chip looks like or whats on it, that would be super, pictures are great)

Eric's Turbo Tweek chips are great, thats what I switched too also, but I would still confirm what you have as a starting point.
Click to expand...

tta983 said:
Here is the chip that came in my tta, I just put turbo tweak classic chip in. What a difference, it idles better, it runs better, it runs cooler and turbo spools up faster. What a great chip.View attachment 1925
Click to expand...

Thanks for the help. I will look into it today.
 
nice to see that i'm not the only one who has Smog troubles with the great state of california....thanks Arnie!
 
UPDATE
I replaced the MAF as suggested by a member here and the car is running a lot smoother. No more hesitation or stalling.

I do have one more problem. The car also failed the EVAP test. I replaced the gas cap, but I think there is more to the problem since they hooked up a machine to the gas filler that eliminated the cap during the test. Anywhere specific I should be looking? Thanks.
 
I didn't think these cars had that capability being 1989 OBD1. WOW is California strict. Anywho, There should be an evap charcoal canister & a purge valve to control the amount of fuel vapor. If the purge valve is stuck open or if the canister is cracked, it will fail the test, being 1989 it should be a VERY basic system.

I really thought, they only checked evap test on 1996 OBD2 & up were its monitored by the ecm... I learn something new everyday...
 
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