GenIII missing after extractors fitted

[Anglosaxon]

Hi all,

Got a problem wondering if its common, I have a VT SS gen 3, I've fitted a twin 2.5 inch Xforce system then 4 into 1 pacemakers with custom made highflow cats, after fitting the extractors and cats I get an engine warning light not always but very often, and in spite of the fact the car feels WAY more responsive and has a lot more power I'm sure its missing and it sounds rough, I'm still getting used to the huge change in exhaust sound so I'm not 100% sure but it definitely sounds not right. Is this because the PCM needs retuning to the changed exhaust? I plan to get my PCM flashed with a mafless tune and to take out the maf sensor next week. Is it better to get a custom (dyno) tune or will an "off the shelf" reflash tune be ok? On a learning curve here any advice appreciated.

Cheers,,

 

[ryan101]

O2s common problem after extractor install! And maybe you broke a spark plug, or a loose lead causing your miss

 

[Anglosaxon]

Yeah checked the leads, actually took the coil packs off today to change leaky valve cover gaskets so gave them a good check all seem ok, you never know though maybe even a coil, just found out a bloke I know has a fault code scanner he is dropping it around later tonight hopefully that'll shed some light on it for me.

 

[ryan101]

Just check all the plugs for the coils you had to remove! Did you check you didn't knock a spark plug and damage one? I'm still thinken O2 sensors for the light! How long have you had the extractors on for?

 

[Anglosaxon]

The extractors and cats were just fitted (professionally) the other day, the cat back exhaust has been on for ages, yeah have checked the plugs, but the miss isnt contant, it doesnt sound like its missing at low revs or idle, mainly during acceleration, i think, as i said im still getting used to the sound it makes now,,,

 

[ryan101]

Mine kinda has a popy idle sounds like I miss but I've been told its normal! With new extractors the have a coat of oily stuff so they don't rust and when you put them on for the first time that oil ends up on the O2s and stuffs them, so you maybe up for a new pair! Just see wat the scanner says when your mate gets there

 

[Anglosaxon]

Yeah I got my mates scanner and checked the codes, its the O2 sensors alright, low heat on both, suppose they need replacing??

 

[Munz]

did you need 02 extensions? If yes, low heat means they aren't performing there best as they have been moved further away from the original position. Need a tech2 or tuner to remove/clear codes and reset

Low voltage on the other hand usually needs new 02's

 

[Not_An_Abba_Fan]

The coating inside the extractors generally causes O2 sensors to fail after fitting new ones.

I'd check for a cracked plug, very common to crack one when fitting extractors on the LS1. Another thing to check, but you would have found it if you removed the leads, is that when removing leads you can pull the lead out of the boot on the plug end if it isn't done correctly as they can be tight. Then when trying to put it back together it doesn't contact properly and misses under load.

 

[vk_calais5.0]

thought it was only the 6litres that needed O2 sensor extension..

i got similar exhaust setup last week with twin system and i have a VIBRATION at
1500-1900rpm really annoying.!!