Failed emissions NOx

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  #1  
Old 09-02-2011 | 03:09 AM
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Default Failed emissions NOx

Test Limit (ppm) Tested out at
HC 114 45.9
CO .63 .01
NO 796 1454.7
Co2 13.1

Has a brand new cat (didn't even park it between install and test). I pulled the EGR valve, hardly any carbon but cleaned it anyway.

Will the EGR trip when when you increase the revs? I unhooked the supply line going from the solenoid to the valve and couldn't get any suction. There is plenty going to the solenoid. How common is it for a solenoid to go bad?

Also I read somewhere and now I can't remember that the speed at which you are traveling had something to do with actuating the EGR. Would having a speedo that isn't calibrated affect it?

94 lt1 73kmiles
 
  #2  
Old 09-02-2011 | 11:39 AM
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Well since I am a poor... and impatient I am going to grab that solenoid, plug it in and see if it works. If not I will just return it and see if anyone chimes in.
 

Last edited by robbygz28; 09-02-2011 at 11:56 AM.
  #3  
Old 09-02-2011 | 12:58 PM
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The EGR operates up to 2200 rpm after the car has warmed up. It's more likely that the rubber diaphragm on the valve itself is dry rotted and won't hold vacuum. Pep Boys sells a rebranded MityVac kit for $30. Buy it and see if the EGR holds up.
 
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Old 09-02-2011 | 01:06 PM
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If you're reluctant to spend any money you could do this: Remove the tube vacuum harness from the EGR valve. Start the car and press the diaphragm in so the engine runs rough and hold it in place. Place your finger on the vacuum inlet of the valve to seal it up and let go of the diaphragm. If it moves back and the car returns to a smooth idle you have a leaky EGR.
 
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Old 09-02-2011 | 01:11 PM
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Originally Posted by Catmaigne
If you're reluctant to spend any money you could do this: Remove the tube vacuum harness from the EGR valve. Start the car and press the diaphragm in so the engine runs rough and hold it in place. Place your finger on the vacuum inlet of the valve to seal it up and let go of the diaphragm. If it moves back and the car returns to a smooth idle you have a leaky EGR.
Wow I am a idiot! Thanks a lot am going to go try that now. At first I just unhooked the feed from the EGR and put a extension on the tube but it wasn't actuating didn't even think to plug it myself.

EDIT: Negative on the dry rot btw it actually looks really good.
 
  #6  
Old 09-02-2011 | 01:34 PM
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This doesn't look right to me.
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Also should it be spliced like this:
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Sorry about the blurry cell pics. All my batteries for my d60 are dead. FAIL
Also ignore the coffee I splashed all over the brake booster when I dropped it.
 

Last edited by robbygz28; 09-02-2011 at 02:15 PM.
  #7  
Old 09-02-2011 | 01:42 PM
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Then it must be the solenoid or harness. I was going to suggest using gasket sealant on the valve but it should be fine if your idle varies.

I was told my car sat for a few years with the previous owner so my EGR valve rotted along with a couple other EVAP tubes. I took the cheap route and replaced everything but the valve before even testing it.
 
  #8  
Old 09-02-2011 | 01:44 PM
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Looks like someone bypassed the throttle body.
 
  #9  
Old 09-02-2011 | 01:53 PM
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Originally Posted by Catmaigne
Then it must be the solenoid or harness. I was going to suggest using gasket sealant on the valve but it should be fine if your idle varies.
I replaced the old gasket, brushed the mating surfaces, and used gasket sealer while I had the EGR off to clean it.

Also the PCV valve is connected to where the vacuum is for the vented optispark in this picture
http://shbox.com/1/opti_vacuum_conn.jpg

the splice in the EGR line appears to be going to the optispark. Considering it is a 94 it must have been converted?

I am so confused.

How much vacuum should I have going to the EGR solenoid?
 
  #10  
Old 09-02-2011 | 01:57 PM
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Originally Posted by Catmaigne
Looks like someone bypassed the throttle body.
I cannot see this raising cylinder temps causing high NOx emissions.
Agreed?

Originally Posted by Catmaigne
Then it must be the solenoid or harness.
Solenoid is getting power.


BTW for some comedic relief. Called the local GM dealership to see if they could calibrate my speedo the response I got was "why?" Because I changed the final drive "okay..." Can you do that? "no" Serious? "Changing the gearing wont change your speedo" then he proceeds to tell me it is because I have it set on kmh not mph. I tell him I don't it displays both "No there is a way to switch it, that is what it sounds like to me"
 

Last edited by robbygz28; 09-02-2011 at 03:02 PM.



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