Maryland Emissions
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Maryland Emissions
I have a 1995 F-250 with a 460 motor. It runs great and I have no codes and no lights on in the dash. The truck won't pass the emission test . The nitrogen is to high and the others are almost to high. Does anyone have any thoughts before I just start replacing things.
Posting Guru
Joined: Jan 2003
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From: Still under the hood in O
When was the last time it had a full tune up?
This should include:
plugs
wires
cap/rotor
O2 sensors
fuel and air cleaners
Crankcase breather (the small breather in the airbox)
PCV valve
I would go ahead and do this anyway, the truck WILL thank you with better MPG and performance anyway, so your not throwing money away.
How long did the truck run before testing? You need to have that Cat heated up pretty good to be affective. I used to let it run/drive it for 45 minutes before testing.
Don't let the truck sit not running if there is a line waiting for testing either, this only lets the cat cool down and become ineffective.
Is it possible the cat is worn out?
This should include:
plugs
wires
cap/rotor
O2 sensors
fuel and air cleaners
Crankcase breather (the small breather in the airbox)
PCV valve
I would go ahead and do this anyway, the truck WILL thank you with better MPG and performance anyway, so your not throwing money away.
How long did the truck run before testing? You need to have that Cat heated up pretty good to be affective. I used to let it run/drive it for 45 minutes before testing.
Don't let the truck sit not running if there is a line waiting for testing either, this only lets the cat cool down and become ineffective.
Is it possible the cat is worn out?
Posting Guru
Joined: Jan 2003
Posts: 1,061
Likes: 0
From: Still under the hood in O
In good light, look at the color of it (cold). If it looks reddish it may be getting plugged.
Tapp on it with the palm of your hand and listen for anything that rattles. If it sounds like anything is loose, it needs to be replaced. This is the catalyst materials falling apart.
Tapp on it with the palm of your hand and listen for anything that rattles. If it sounds like anything is loose, it needs to be replaced. This is the catalyst materials falling apart.
