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Model specific boards => Golf mk3 => Topic started by: Dubber.ducky on 26 July 2012, 22:12

Title: Milltek decat and exhaust help
Post by: Dubber.ducky on 26 July 2012, 22:12
I have just fit a decat and exhaust to me vr6 and when turned over it cut out twice no it's stopped after I took it for a run but it smelt a bit rich and mpg have decreased a lot.
Does it take a while for sensor to recognise it has no cat. Just other cars in past includin scooby sti type r increased mpg and did stop smellin rich.
Any feedback will be must obliged
Title: Re: Milltek decat and exhaust help
Post by: tweed on 26 July 2012, 22:26
Do you know what a cat converter does? Of course it will smell rich!

Mpg has dropped because your properly booting it more because you think it sounds better.

There is a chance that you damaged the lamdor sensor on removal. How did you remove it? Because they are a cnut
Title: Re: Milltek decat and exhaust help
Post by: Dubber.ducky on 26 July 2012, 22:29
Yeah I kno It will smell rich but with me scooby an crx's it settled down the smell. Dunno if that's cos it carb'd up.
I don't really boot it tho that's the thing.

Sensor came out once exhaust was on the bench with a lamdor sensor socket from my mates work
Title: Re: Milltek decat and exhaust help
Post by: tweed on 26 July 2012, 22:37
If it's "carb'd up" you don't need a lamda sensor  :rolleyes:

Plus the sensor is placed before the cat. Changing it over should have no effect on how it runs and maps the fuel

Maybe you haven't plugged it in correctly
Title: Re: Milltek decat and exhaust help
Post by: Dubber.ducky on 26 July 2012, 23:12
Il double check tomorrow but sure it went on correctly. If not il try a new one.
Thanks
Title: Re: Milltek decat and exhaust help
Post by: sharki786 on 27 July 2012, 02:43
the ecu will relearn (thats what i was told) and your mpg will increase but as said before, you must be booting it hard, as the zort will sound louder and the sound of a vr, oh mi gosh.

Sharki
Title: Re: Milltek decat and exhaust help
Post by: Dubber.ducky on 27 July 2012, 10:12
Cheers sharki.
Title: Re: Milltek decat and exhaust help
Post by: tweed on 27 July 2012, 18:25
the ecu will relearn (thats what i was told) and your mpg will increase but as said before, you must be booting it hard, as the zort will sound louder and the sound of a vr, oh mi gosh.

Sharki


How will it "relearn"?
The lamdor sensor is before the cat. It will get the same readings
With cat or a decat.   
Title: Re: Milltek decat and exhaust help
Post by: leigh_harty on 27 July 2012, 18:32
the ecu will relearn (thats what i was told) and your mpg will increase but as said before, you must be booting it hard, as the zort will sound louder and the sound of a vr, oh mi gosh.

Sharki


How will it "relearn"?
The lamdor sensor is before the cat. It will get the same readings
With cat or a decat.   

Maybe its the disconnect battery for 30mins trick?

Either way its gunna smell rich and mpg shouldnt be good enough to notice a drop  :grin:
Title: Re: Milltek decat and exhaust help
Post by: sharki786 on 27 July 2012, 19:11
well thats what i was told. But if you replace you cat with a de-cat then the breathing of the car will be less restrictive so more air/fuel mixture is required. Also your throttle response will be more
Title: Re: Milltek decat and exhaust help
Post by: twotwofour on 28 July 2012, 10:49
My guess is a wire has broken on the lambda sensor plug, happened on mine, unfortunately on the wire loom side. Caused exactly the same problems
Title: Re: Milltek decat and exhaust help
Post by: leigh_harty on 28 July 2012, 11:46
My guess is a wire has broken on the lambda sensor plug, happened on mine, unfortunately on the wire loom side. Caused exactly the same problems

The wires can run close to the down pipes and exhaust... but surely thats why their is a heat shield?

Still can go brittle over time thoughy
Title: Re: Milltek decat and exhaust help
Post by: twotwofour on 28 July 2012, 16:26
I'd say mine was used by cack handed grease monkeys pulling on the wires instead of the plug