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2013 Chevrolet Suburban
Platform: GMT 400, 800, 900

high CO emissions

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Old December 27th, 2008, 7:35 PM
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Default high CO emissions

Hello,
My 95 Suburban won't pass our county emissions for the 1st. time in 14 years for a higher than normal CO output.

Does anyone know what will cause this ?

The readings are as follow:
CO 2500RPM 2.15 The limit is 1.20 FAIL
CO Idle3.22 The limit is 1.20 FAIL

This is a 454 throttle body type fuel injection
Old December 27th, 2008, 8:31 PM
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Default RE: high CO emissions

Can you give the all other emissions numbers.
Old December 27th, 2008, 10:16 PM
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Default RE: high CO emissions

Sure,

HC 2500RPM 37.8 Limit 220.0
CO2 2500RPM 13.53

HC Idle121.2 Limit 220.0
CO2 Idle 12.86
EVAP Gas Cap 27.90 In H20 Limit 6.00
Old January 2nd, 2009, 4:08 PM
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Default RE: high CO emissions

Any ideas ??
Old January 4th, 2009, 10:14 PM
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Default RE: high CO emissions

Is the cat . converter original? I would highly suspect it. Do they test nox in your area? If so what is the reading.
Old January 5th, 2009, 7:54 AM
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Default RE: high CO emissions

MDTAHOE,
I have only driven this truck about 3000 miles in the last 2 years. And I replaced the converter then (2yrs. ago) with a aftermarket converter. At that time it was running rich due to a faulty coolant sensor. And NO i do not see anything about NOX.
Thanks, Jack
Old January 5th, 2009, 6:21 PM
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Default RE: high CO emissions

MDTAHOE,
I spoke with another mechanic today and he said on a vehicle like this the two most common causes would be high fuel pressure or a faulty injector. He said he would check the inlet /outlet temperatures first (they should be 100 degrees difference) if the converter was active? Would you tell me what you think before i go replacing parts I can't already afford ?

Thankyou !
Old January 5th, 2009, 9:18 PM
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Default RE: high CO emissions

CO
Old January 5th, 2009, 9:26 PM
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Default RE: high CO emissions

CO is a measure of fuel mixture. HC is a measure of unburnt fuel.CO2 is a measure of efficiency anthing over 12.00 is good.If you had a bad injector or high fuel pressure your HC would be extremly high and co2 would be very low. Most things that effect CO should effect other numbers except the converter. You can not check converter function that way all you can check is if it is restricted. You need a shop with a emissions scope to perform a oxygen capture test on the cat. Even though it is new it does not mean it is good. I have had sever aftermarket cats bad out of the box. A bad injector ar high fuel pressure can be proved or dis-proved in less than 10 minutes with a pressure gauge.
Old January 5th, 2009, 9:53 PM
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Default RE: high CO emissions

OK, So you suspect the converter as your first thought.
Is there an after market brand you would use or do I go to the Dealer?

Thanks So much !

Jack


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