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JCMack's avatar
JCMack
Explorer
May 09, 2016

emission failure on an 05 workhorse chassis 8.1 engine

I am trying to get my 8.1 engine to pass it's emission test which it failed last week. Oil has been changed, air filter new, MAF cleaned, so i am thinking as it runs rich it could be an O2 sensor. I c...
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enblethen's avatar
enblethen
Nomad
May 09, 2016
Some OBD II readers show the exact measurements of each of the sensors. This should tell you which sensor is out of limits.
my $50 dollar one from Harbor Freight does this. You would need to get the sensor parameters for your exact year. OBD II tester
It could be the idle control valve. Not sure if 8.1 has one. It acts like a choke for Fuel injection.

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