Getting to the end of my teather so I'm giving it one last go then I'm weighing it in.

I'm getting few trouble codes:

16684 multiple miss fire

16687 cylinder 3 miss fire

17705 pressure drop between turbo to dv

16795 secondary air pump.

The car runs fine, but when its starting to boost it gets hesitant like the boost it being cut, I baught the car 2 weeks ago. The test drive it drove mint. Journey home it was a bit hesitant when coming on boost. A week later of running like this it stopped boosting all together the the exhaust impeller fell off. Changed the turbo for a ko3 and it was mint for a day or so and now is as bad as ever hesitant etc. Any idea what to check or change?

Cheers

coil packs i believe are your issue, and a common problem at that.

check for boot pipe leaks

Edited 18 September, 201213 yr by Lofty79

And your turbo should be a ko3s, not ko3...

I'd be checking the diverter out too, not just coil packs.

Think is the engine is silky smooth. Not missing to the ear, runs mint and drives fine unroll it boosts..

I know it should be a 3s but their like hens teeth to get hold of as I won't have one posted as want to check play and end float in the bearings

If its only a k03 then it may not be able to produce boost required at certain rpm that the ecu thinks it should be producing hence the underboost fault code.

Have you had plugs out checked them and swopped coilpacks around to see if misfire moves cylinders.

When it's boosting that's when the ignition system is under most load. Have you checked to see if your car has had the coil pack recall done? If not you could get a free set for nowt!

Mine brought those codes up a while back when was it last serviced? I changed the plugs had no issues with missfires plus the battery was on its way out which didn't help and i put a better dv valve on cured the boost issue also

The first two sound like coil packs . Not so long ago skoda was doing a recall on there cars to re-place the coils free . So might be worth giving them a ring and asking them . The 17705 code is a nightmare to cure ! It can be down to many of things . Do a search on here and you will get some idea . I did cure mine and did write a thread about what I've done to cure it . As for the secondary air pump many people on this site have taken it off as its not really needed . There should be a guide I think on here how to do it . If all else fails book it on to skoda and get them to put it on the computer and they will tell you whats wrong and source new or second hand parts to fix it . 

It's just been serviced. New plugs etc, I can honestly say I've not felt a glimmer of a miss fire which is what baffles me.. ill have a look tonight at a few more things n swap coils around etc

Out on a limb here. I would suggested checking the fuel rail for contaminants and possibly replacing the fuel line pressure regulator. (Often overlooked regarding misfires) Clean the throttle body and clean the sudo EGR valve out.

I would also make sure there is no muck in the pipework going to and from the N75 Valve.

I had a combination of All of the above and gradually I solved all of it.

So Far My Rs has done 6.5K without a fault stored.

Cheers mate, I replaced n75 valve last night, swapped coilpacks with a mates n the codes went but still hesitant on boost, will checks pipes are clear tonight n might try his Maf etc too

Probably because it's as lean as hell with the wrong turbo, unless you've had it mapped to suit...

It was running like this with the old turbo on.

Ah yeah, so you did.

Clean the throttle body, unplug the maf and see how it runs disconnected.

Cheers will try tonight matey

Just read about the wrong turbo , Youve got the 150bhp turbo not 180bhp turbo . Theres a turbo for the VRS for sale on here might be worth getting that and changing it and see what codes you get then

I've seen it, but Im major skint so ill have to hold fire for s while on that ::(

It's just showing 17705 now, pressure drop from turbo to dump valve.. if I'm checking for split pipes can I do the good old trick of spraying summit over the pipes and listen for engine note change? Or is it more a visual thing? Also after I've cleaned the throttle pot how do I reset it?

Cheers all

When I first had my vrs I had a persistent 17705 until I cleaned the throttle body, result? - no more code.The gasket costs very little and the body can easily be cleaned if you leave the electrics connected and have a 2nd person to keep throttle open while you clean.

Superb, ill get the Mrs to help lol! Thanks matey!

Throttle pot spotless and no obvious leaks... Still the same :'(:'(:'(:'(:'(

Had all pipes off and no leake :(