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Model specific boards => Golf mk4 => Topic started by: DubAndDubber on 23 July 2013, 18:47

Title: Post Cat Lambda Spacer
Post by: DubAndDubber on 23 July 2013, 18:47
Fitted my decat a few weeks back and didn't sort out the lambda issue.

What do I need to do to remove the EML?

I've read that some kind of spacer does the trick, or washers?

Any help would be great.

Thanks
Title: Re: Post Cat Lambda Spacer
Post by: ben.banks21 on 23 July 2013, 18:51
get it mapped out. i now if you use a spacer on the agu pre cat sensor the car runs very lean.
Title: Re: Post Cat Lambda Spacer
Post by: DubAndDubber on 23 July 2013, 19:30
I have an AUM. Already had a map too.
Title: Re: Post Cat Lambda Spacer
Post by: Granta Gti on 23 July 2013, 19:43
get it mapped out. i now if you use a spacer on the agu pre cat sensor the car runs very lean.

You shouldn't need to space a pre cat  :undecided:
Title: Re: Post Cat Lambda Spacer
Post by: navmk4gti on 23 July 2013, 21:34
I had decat on my agu was fine..no lights nothing  :undecided: as for aum map it out
Title: Re: Post Cat Lambda Spacer
Post by: DubAndDubber on 23 July 2013, 21:38
I'm hoping Dom will come along and help me out...
Title: Re: Post Cat Lambda Spacer
Post by: dom on 23 July 2013, 22:06
I'm hoping Dom will come along and help me out...

You called? :grin:

I'm lucky in that my decat hasn't thrown the EML on. You have 2 options, first is to have it mapped out, second is to space the post-cat lambda, not the pre-cat one as has been suggested.

The pre-cat one controls fuelling, post-cat just checks that the emissions are within an acceptable range and isn't really needed. By spacing the post-cat sensor it will read the emissions to be lower than they actually are, therefore in most cases preventing the EML from coming on.

Something like this...

http://www.ebay.co.uk/itm/LAMBDA-O2-OXYGEN-SENSOR-BOSS-EXTENDER-SPACER-FOR-DECAT-FROM-HIGH-GRADE-STEEL-/161046047401?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item257f17aaa9 (http://www.ebay.co.uk/itm/LAMBDA-O2-OXYGEN-SENSOR-BOSS-EXTENDER-SPACER-FOR-DECAT-FROM-HIGH-GRADE-STEEL-/161046047401?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item257f17aaa9)

I'd check the thread is correct before buying though, use your cat if you still have it :wink:
Title: Re: Post Cat Lambda Spacer
Post by: ben.banks21 on 23 July 2013, 22:10
get it mapped out. i now if you use a spacer on the agu pre cat sensor the car runs very lean.

You shouldn't need to space a pre cat  :undecided:

i had to on my agu because the 3" straight through Exhaust system i brought from the US had the lambda sensor hole on the downpipe too close to the fire wall so i had to buy a 90 degree spacer which in turn caused it to run very lean.
Title: Re: Post Cat Lambda Spacer
Post by: dom on 23 July 2013, 22:15
get it mapped out. i now if you use a spacer on the agu pre cat sensor the car runs very lean.

You shouldn't need to space a pre cat  :undecided:

i had to on my agu because the 3" straight through Exhaust system i brought from the US had the lambda sensor hole on the downpipe too close to the fire wall so i had to buy a 90 degree spacer which in turn caused it to run very lean.

It will have been running lean due to the false reading, was it a cheap decat? I'm running a 3" one from the US and had no such issues.
Title: Re: Post Cat Lambda Spacer
Post by: DubAndDubber on 23 July 2013, 22:16
Thanks Dom! I remember reading through your dub rides section, but I wasn't searching through it to find out  :grin:.

Thanks for that, the car isn't driving bad, if anything it's better. But that bloody light drives me nuts!
Title: Re: Post Cat Lambda Spacer
Post by: GTi_James on 23 July 2013, 22:31
mk4 aum with decat, i have the right angle spacer on after cat and no light, no codes. engine runs a lot smoother and i have noticed better MPG though dont know if thats a combination of hot weather as well. managing 150 miles a week with 2/8ths of a tank used only  :smug:
Title: Re: Post Cat Lambda Spacer
Post by: ben.banks21 on 23 July 2013, 22:47
get it mapped out. i now if you use a spacer on the agu pre cat sensor the car runs very lean.

You shouldn't need to space a pre cat  :undecided:

i had to on my agu because the 3" straight through Exhaust system i brought from the US had the lambda sensor hole on the downpipe too close to the fire wall so i had to buy a 90 degree spacer which in turn caused it to run very lean.

It will have been running lean due to the false reading, was it a cheap decat? I'm running a 3" one from the US and had no such issues.

when my car went for custom mapping at rtech i had to have the lambda sensor hole moved on my downpipe because the 90 degree spacer was giving false readings causing the car to run lean.
Title: Re: Post Cat Lambda Spacer
Post by: westylakey on 24 July 2013, 08:29
I have cable tied my post cat sensor to the subframe and left the blanking plug in the decat. No lights yet.