EGR and PFE servicing....was: Re: [Shotimes] Codes

[George Fourchy]

On Wed, 11 Aug 2004 20:44:40 -0700, Kirk Jorgenson wrote:

>The first two codes are related(I think): 31, 33
>These are related to the EGR valve and the passageway or something being 
>plugged.

There is the EGR valve itself, and the PFE sensor just below it.  PFE stands for
'pressure feedback E(GR)'.  It tells the computer just how much the EGR valve has
opened and whether it is doing what the computer has told it to do.  Gen 2 cars have
a DPFE, where the D stands for differential pressure....measuring EGR flow on both
sides of the sensor.  Gen 1 cars just measure it being on or not.

The first thing you should do is clean out the passages on the intake that the EGR
flow uses to get to the airflow.  It theoretically could be done on the car, but I'd
take the manifold off and do it on the garage floor.  Once this is done, a lot of
EGR problems go away, and the car runs much cleaner regarding NOX emissions.  You
have to take the throttle body off the intake to get to the EGR passages where they
come out into the airflow....a coat hangar wire is good to clean them with.  It only
took a few minutes to clean them once the manifold was apart.  Theoretically, one
cleaning should be good for the life of the car, if Lowrider is any indication.  It
passed its smog check last summer, yet the passages were just about plugged, with
277k miles.  Then it had its PFE problem (sensor falling off the head, and shorting
the connector wires).  The passages are clean now, and I'd hope I don't have to
clean them again.  The new cars will have them cleaned before they enter service,
and that should do it for their lifespan....they won't get the high miles Lowrider
did.

George