1990 4runner wont pass emissions.

10-26-2009, 10:24 PM
First time I took it thru the readings were this.
co 62.42
nox 5.62
I put a new catilylic converter and o2 sensor.I ran it thru again today and passed all but the carbon monoxide but it went from 62.42 to 35.88 ,I need to be at 20.00.
If anyone would know what I need to change out to get it down or any adjustments I would need to do it would be greatly appreciated.
TIA.: )

Brian R.
10-27-2009, 07:29 AM
High CO with good HC would seem to indicate that you have too much fuel, but it is burning efficiently. Test your Engine Coolant Temperature sensor and replace if out of spec. Test your VAF meter and Inlet Air Temperature sensor. Clean your throttle body.

10-28-2009, 08:08 PM
Thanks for the help.it seems my EGR valve wasnt plugged in.
Plug it in and it passed with flying colors...lol

Brian R.
10-29-2009, 12:40 AM
Good job!

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