hey guys,

can you de-cat a zetec se run on the standard ecu?

the engine has a pre and post cat sensor and iv been told that if i just ditch the cat the engine won't run properly as the ecu takes info from the post cat sensor and adjusts the fueling.

does anyone know if this is true? if so is there a way around this?

many thanks for all help and advise.

Yep its true it will throw a code to say the cat is buggered and may go into limp home mode.

you are able to get a device that tricks it in to thinking the cat is there.

edit.

Do a search for MIL Iliminator

or the bluefin

[Edited on 5/4/10 by big_wasa]

To explain a bit.

In normal closed loop running when up to temp a standard zirconia pre-cat sensor should give a varying output which flickers up and down between about 0.1v and 0.84v --- the output is never constant. Mechanics often refer to this as the lambda sensor "switching".

Id the cat is working properly the post cat sensor however should give a fairly constant output.

After warm up the ECU looks to see if the pre-cat sensor signal is "switching" up and down and then compares it with the post cat sensor. The two readings should almost never be the the same. If the readings are the same or similar the ECU flags up a fault code.

[Edited on 6/4/10 by britishtrident]

[Edited on 6/4/10 by britishtrident]

thanks guys,

my next question is where can i get one of these o2 cheaters???

i had a look but they seem to be in the us

can i make one? and if so how?

many thanks guys

Here's one (expensive for a couple of resistors and caps though).

http://www.ptp-ltd.co.uk/shop/258_111/mg_rover/mgf__mg_tf/exhaust_systems/mil_eliminator_(malfunction_indicator_lampcheck_engine_light).htm?

Reading the PDF it looks like a simple filter circuit, but I'm not an analogue electronics expert so wouldn't want to hazard guesses on component values.