2001 wrx ppp 4"mongoose with de-cat fitted had car about 6weeks now started to run crap few days ago then light on dash came on took to garage for diagnostic check fault code P0420 (catalyst efficiency) garage reset ecu car seems fine now but guy in garage says will most prob do the same again as no cat fitted is there any way around this or should i be thinkin of fittin a cat

 

if you get a remap it will remove the problem as they change readings of the sensor, it comes on because i think its reading that the temperature is to high so it puts the cel light, the light will come back on normally when you get on the motorway and the car is well warmed up as its just recently happend to me but its been fine since getting remapped. i think if you dont want to get a remap you can get a resistor from maplins that connects to the sensor and stops it reading correctly but dont quote me on it

 

cheers for reply do you no were the best place to take for remap am from wrexham area

 

You don't need a remap to put the light out, you can have a little electronic box of tricks fitted to the Engine Ecu harness to cure your problem & it's a shed load cheaper than re mapping!

Your exhaust system has 2x sensors fitted in the exhaust, the first sensor sniffs the exhaust gas to check how rich/weak the engine is running, which in turn allows you Ecu to adjust the fueling.

The second sensor is fitted just after where your catalyst was and it's job is to sniff the exhaust gas to make sure the catalyst is running efficiently. The box of tricks interferes with this signal and makes the Ecu think that the cat is still there & everything is ok.

This is quite a popular mod so I would talk to your local Subaru Specialist about it.

Phil

 

cheer phil will give them ring on monday to see if they can help

 

i would still have the remap done regardless of the £650 cost.

running a decat on the original ppp map is asking for trouble the boost and fuelling will be out because of increased flow and lack of back pressure.

by all means fit the box of tricks to interfere with the signal from rear lambda sensor but a £650 remap is far cheaper than rebuilding an engine that has melted a piston.

also without the remap you will not get the full benefit of the decat either

 

I agree a cel-fix would put the light out. But ultimatly a re-map is the way to go. You have know idea what afr's etc are at the moment. Unless youve had them checked?

A remap with a de-cat,Fuel pump and panel filter will give some great performance gains

 

There is no problem with de catting your bugeye (apart from MOT)

the Newage ECU can handle the change in air flow / boost / fuel for the TD04 turbo you have

If the car is not running right then it's not the de-cat as the ECU throws the CEL but DOES NOT affect performance.

CEL fix's are not 100% effective as the newage ECU expects to see a changing signal from the rear Lambda sensor.

Personally I'd go for a ecutek re-map which will improve performance and get rid of the P0420 CEL for good

Shaun