View Single Post
scarceller scarceller is offline
Registered User
 
scarceller's Avatar
 
Join Date: Oct 2006
Location: Southern MA
Posts: 3,585
Garage
Very likely the CAT is bad.

But the slightly high NOx could also be one or more faulty injectors. A lean running cyl can cause NOx to go up.

Then the O2 sensor sees the average O2 content from all 6 cyls, if one cyl is running very lean because of a clogged injector that will increase NOx and it will also cause the other 5 cyls to go slightly rich because the O2 sensor sees a slight lean condition because of the one lean cyl, the DME will then richen the other 5 cyls and then HC also goes up.

Usually if NOx is high HC is low, but the above explanation is something to think about. A faulty clogged injector could result in both NOx and HC going up.
__________________
Sal
1984 911 Carrera Cab M491 (Factory Wide Body)
1975 911S Targa (SOLD)
1964 356SC (SOLD)
1987 Ford Mustang LX 5.0 Convertible
Old 02-18-2019, 09:42 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #17 (permalink)