Evening all,

Bypassed the N249 yesterday, having gotten fed up of a jerky car! Good news is it drives much better, with more apparent boost and response, so I'll assume the N249 valve was a bit poorly...

I do, however, now have an engine management light. The car drives absolutely fine; infact better than before, so I'm assuming it is just recognising something has changed. My question is though, should I get an engine light? I haven't touched any electrial connectors, I just removed the vac line from the underside of the inlet, and blocked it off. I then took the other end off the DV and blocked that pipe off. FInally, I ran a silicone vac pipe straight from the inlet manifold to the DV.

Is this correct, or should I have done something differently? The SAI is still present on the car, though I plan on removing it over the next couple of weeks. I've just thought though, I assume that the N249 is connected inline with the N112 somehow? If I have just blocked the vac line from the inlet to N249 will I have upset the N112 valve as well?

Cheers

Sam

They both run off that feed, if the valves been trying to open dv to stop it overboosting and carn't then it will put fault code in, either that or lambas picked up that sai's not doing much, it will be on once you take all lot off anyway so i wouldn't worry about it,

I had shark map mine out when i had car remapped along with second lamba so i can decat it, so i no longer have light on

I agree the codes will be there anyway once removed, and I intend to have them mapped out when it goes for a remap.

Thanks for clearing that up, I thought I had probably confused something lol, but at least it isn't major.

Thanks again.

If you haven't removed the secondary air system you still need a vac feed for the N112 valve otherwise it can't open the combi valve on the exhaust manifold for a cold start. You need to either leave a vac feed from the inlet manifold to the loop between the N112 and vac reservoir or remove the whole SAI system and N112 altogether

I did think that... Will it do any harm leaving it for a few days like it is? To be honest, I'm probably going to remove the SAI on Saturday, as I have all the bits and I want to get rid of it.

Just a quick question... I noticed last night that I seem to be getting boost fluctuations again. The car pulls stronger overall so I assume the N249 was holding it back. Would a boost leak cause this or would it just feel generally 'flat' power wise? I get what I deem to be a rather loud hissing noise from the drivers wheel arch when coming on boost; I guess I need to check the turbo to pancake pipe. I just don't think it should be that loud.

Normally if you get boost fluctuations its down to either a dodgy remap, the N75, or the actuator. Or what you think are boost fluctations may be nothing to do with the boost and are down to ignition or fueling.

If you have a large boost leak then you wouldn't get fluctations, the car would just have practically no boost and it would throw a 17705 code.

Worth checking the large boost pipes between the turbo and throttle as you've already said. If you've never cleaned your throttle body then do that too as it will make it run a lot smoother, and try and find out what the stored fault code is - it may even be something unrelated to your N249 removal.

I did have a 17705 code diagnosed, but to be honest I haven't checked recently whether it has gone, but I have removed/replaced certain pipes to try and rectify this - After looking at advice on here I decided to try this first instead of the N75. I Cleaned the TB last year which made it idle and drive much better, but didn't cure the fluctuation. I suppose it could be the N75 or actuator, though I imagine only a tuner would be able to diagnose the actuator?

I have the catch can fitted, with all new piping, and have removed and blanked off the usual culprits under the inlet manifold, along with simplifying the pipes to the brake servo. Really the only thing I haven't done is checked the turbo to pancake pipe, and tried another N75.

This weekend I intend to remove the SAI and N249 system so I can rule any issues out there.

Part of my problem is I have only ever driven two of these cars, the other being my best mates, which has definately been mapped, as it's a totally different beast, so I can't tell if mine is down on power. It drives very well, I just think it's lacking a bit. Low to midrange revs wise it isn't too bad, but it almost feels like an N/A engine at higher revs. I can still hear the DV when changing gear at high revs, but it just doesn't feel like it's doing alot.

Edited 14 March, 201214 yr by sjh1986

Ask about on here and see if there's any members near you that have got a standard one you can have a go in (although standard ones are getting few and far between these days!)

You can check the actuator operation yourself by undoing the vac hose from the N75 to the actuator capsule and applying air pressure/vacuum to it and seeing if the rod moves smoothly in and out. If it's sticking it should be obvious.

Good luck with it, hopefully the N249 and SAI removal will help, even if it doesn't directly fix it then while doing the work you might find a pipe thats split that is the cause of the problem.

Ask about on here and see if there's any members near you that have got a standard one you can have a go in (although standard ones are getting few and far between these days!)

You can check the actuator operation yourself by undoing the vac hose from the N75 to the actuator capsule and applying air pressure/vacuum to it and seeing if the rod moves smoothly in and out. If it's sticking it should be obvious.

Good luck with it, hopefully the N249 and SAI removal will help, even if it doesn't directly fix it then while doing the work you might find a pipe thats split that is the cause of the problem.

Thanks buddy, really helpful! I'll give the actuator a quick test and see what result I get. Think I shall ask my mate if I can borrow his N75 to see what effect that has on mine.

Cheers