C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

89 failed emissions

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Old Sep 28, 2007 | 01:31 PM
  #1  
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From: Chandler Az
Default 89 failed emissions

I'm sure you guys have heard this b4..
I bought a 17k low mile vert, went to get registered in AZ and failed the CO only.
The car starts right up and as it warms up it idles a little rougher while in drive. It definitly seems to be running rich (smell)
I bought it from the original owner and it has only been driven 300 miles in the last 4 years.
I have sucked on the FP regulator to see if there is gas (none)
Changed gas filter, seemed clean, does not miss, replaced the thermostat back to the 195 was 180, and i have a new oxy sensor that i will put in. Old one was original....everything is original
What is the closed loop i hear everybody talking about..I have a FSM for my 87 dont know it it is same for the 89.
I get 1 free retest and dont want to miss something obvious.
Dont want to take somewhere YET as i hope i can track down myself.
Dont want to blow it off as the cat seems real hot!!
THANKS!!!
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Old Sep 28, 2007 | 03:41 PM
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From: Austin Tx
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After the engine warms up it goes into closed loop where the o2 sensor gives feed back to the computer to adjust the fuel air mixture. Optimal
ratio is 14.7 to 1
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Old Sep 28, 2007 | 03:55 PM
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You need to scan it to check fuel delivery. If it's deadon, the Cat is probably shot. If it's lean, air is coming in from somewhere other than the throttle body and tricking the Oxygen Sensor into adding more fuel than it needs. If it's rich, check the air filter and injectors. Clamp off the canister feed and if it swings back to lean, the evaporative emission controls have a problem.
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Old Sep 28, 2007 | 05:51 PM
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From: Austin Tx
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Originally Posted by SunCr
You need to scan it to check fuel delivery. If it's deadon, the Cat is probably shot. If it's lean, air is coming in from somewhere other than the throttle body and tricking the Oxygen Sensor into adding more fuel than it needs. If it's rich, check the air filter and injectors. Clamp off the canister feed and if it swings back to lean, the evaporative emission controls have a problem.
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Old Sep 28, 2007 | 08:30 PM
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Arizona emissions SUCK to pass.
What grade of fuel you use and what you put in it makes a HUGE impact on the results.

My first time through i failed everything except one.
Then i ran through with premium gas and this injector cleaner(thats designed for emissions supposedly) and Passed the other two tests but failed the one i had passed before.

Finally i went through a third time with middle grade gas and the injector cleaner and passed.

If you still dont pass you might want to check into replacing your ERG valve.

When you do finally pass PAY THE EXTRA $$ for the 2 year sticker. you'll thank yourself.
Stupid Arizona..

Last edited by bdahl; Sep 28, 2007 at 08:35 PM.
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Old Sep 29, 2007 | 01:05 AM
  #6  
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the easiest sollution is to slip the guy a 50$....that should get you a sticker
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Old Sep 29, 2007 | 03:32 AM
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Axesolo, you've obviously never been to AZ.
Our emissions suckkk They'd probably call the cops on you if you tryed that or at least tell you to leave.
Worth a try though i guess

Getting that stupid sticker is about feels about as hard as picking up a PhD sometimes.
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Old Sep 29, 2007 | 07:42 AM
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One "trick" that I heard of and used, although maybe I didn't need it was to disconnect the EST wire.

Start the car with it disconnected and you might have to help it idle for the first 10 seconds or so. Basically this runs the car off the base timing of 6 - 10 degrees and mine passed with flying colours.

Worth a shot, although it will show a Service Engine Soon light, so if the dude isnt' picky , I imagine they'd let that go.
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Old Sep 29, 2007 | 07:48 AM
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From: Chandler Az
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ok, I replaced the O2 sensor. On the right side of block between the last 2 plugs is a temp sensor, when i unplug it the dash read goes to low so i assume thats ok..Is there another temp sensor? there is not one on the left side between the first 2 plugs. I want to confirm the closed loop thing. I would say it idles slightly better. Road driveability is great. I am going to get some injector cleaner and take a 50 mile drive to see if that hepls....i have only driven it 25 miles total in the 2 months i have had it...too dam hot here in AZ!!! Will let you know. Any other ideas will be great
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Old Sep 29, 2007 | 03:36 PM
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I put some injector cleaner in and too a 50 mile ride. I got SES light once and have a code 45 stored (rich exhaust). Car still idles a little rough. Any more ideas?
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Old Sep 30, 2007 | 08:09 AM
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Originally Posted by axesolo03
the easiest sollution is to slip the guy a 50$....that should get you a sticker
.....
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Old Oct 1, 2007 | 04:57 AM
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Originally Posted by Da Mail Man
.....


Works in So Cal...
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