Omega Owners Forum
Omega Help Area => Maintenance Guides => Topic started by: Welung666 on 20 September 2009, 17:05:46
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This is cure the for the P0420/P0430 codes brought on by failing pre-cats.
Cats are courtesy of MarkMV6.
Lets start with a little theory!..... On each bank there are 2 cats (a pre-cat and a main cat) and 2 02 sensors. As this pipe comes off the manifold there is the first (pre-cat) 02 sensor, then the pre-cat itself. Behind that is the 2nd 02 sensor followed by the main cat. The engine management ECU takes reading from all 4 02 sensors and adjust the fueling accordingly.
When the pre-cats start to fail their efficiency drops causing the P0420/P0430 code(s) to show. This fix will fool the ECU into thinking the pre-cats are working at full efficiency.
Firstly you need to order some lambda boss's and plugs. These are readily available from a well known auction site ;)
Fit the threaded plug with the copper/aluminium washer to the 02 sensor hole between the 2 cats.
(http://images.omegaowners.com/images/guides/move_lambda_sensors/DSCF0706.jpg)
(http://images.omegaowners.com/images/guides/move_lambda_sensors/DSCF0707.jpg)
(http://images.omegaowners.com/images/guides/move_lambda_sensors/DSCF0708.jpg)
Then you need to cut a hole ready to take the new boss. Really you should use a 1" (25mm) hole saw but the metal has been heated and cooled so many times it hardened beyond belief, so we cheated! ;D Out came the angle grinder and we ground a 1" (25mm) square hole and placed the boss snugly in the new hole.
(http://images.omegaowners.com/images/guides/move_lambda_sensors/DSCF0709.jpg)
Then with a good qualitly MIG welder (unlike mine >:( ) neatly seam weld them in place.
(http://images.omegaowners.com/images/guides/move_lambda_sensors/DSCF0710.jpg)
(http://images.omegaowners.com/images/guides/move_lambda_sensors/DSCF0711.jpg)
You just have to re-fit them (well Mark does ;D ) and re-fit the 02 sensors.
The wire for the re-homed 02 sonsor is plenty long enough to reach on vehicles with automatic gearbox, on manual boxes, the wires will need extending slightly in order to ensure that they do not foul on the gearbox output shaft harmonic damper.