Cold start problem

[dom]

Right, not very often I have to start a thread to find a solution but had a search and can't find anything that helps.

I've had an intermittent cold start problem for a while, it only happens if the car has been stood for a long period and it has either been very cold or very wet.

The problem:

Engine turns over fine & idles fine until I go to pull away, then the revs drop and it sounds/feels like it's missing. The car will move but has no power and feels like it is about to stall. This all stops as soon as it is given a decent blip of the throttle. Once it's been given a boot full (with the clutch down), it pulls away fine.

I've scanned it for fault codes and the only code that was shown is:

17608: Recirculating valve for turbocharger - N249-, mechanical malfunction.

The N249 has been bypassed, so I doubt this is related.

Any suggestions with where to begin would be appreciated

[golfyste]

Are the resistors you have used still ok??
My resistors broke on one f the ends so got some better ones 

[dom]

Are the resistors you have used still ok??
My resistors broke on one f the ends so got some better ones 

No idea, I'll check at the weekend. I doubt that's the issue though, I did the N249 bypass well over a year ago, the cold start problem began a few weeks ago

[golfyste]

Hmmm it's a bit with tere not being any fault codes.
I would say check the usual - unplug maf, check throttle body, splits in hoses, all plugs and maybe remove clean and apply electrical grease to stop water penetration, and keep your eye out for codes I guess 

[dom]

Hmmm it's a bit with tere not being any fault codes.
I would say check the usual - unplug maf, check throttle body, splits in hoses, all plugs and maybe remove clean and apply electrical grease to stop water penetration, and keep your eye out for codes I guess 

Yeah the fact there are no codes is what has me baffled.

It had a new genuine VW MAF last October, I've checked all the usual hoses for splits and the look ok, throttle body is fairly clean, but I'm going to give it a proper clean up anyway. It's due a full service soon, so it'll be getting new plugs then. I'll scan it again at the weekend just to check nothing else has been thrown up in the last week or so.

[golfyste]

Hmm all you can do really could be the plugs if they are due to be changed.
Update of you find anythin 

[brianpologti]

Temp sensor as I ve heard they don't always show up, like crank shaft sensor,

[Dalo Harkin]

I know you have a decat, but those symptoms sound like lambda to me, especially from cold

[dom]

I know you have a decat, but those symptoms sound like lambda to me, especially from cold

Hmmm, well the 2nd lambda hasn't been coded out since the decat. Although I assumed that it would throw up the CEL light, or at least a fault code?

Temp sensor as I ve heard they don't always show up, like crank shaft sensor,

It's a possibility but the temp gauge is reading fine

[dan2252]

Temp sensor could be somthing to think about Dom, when I first got mine it had a £6 temp sensor in and had the exact same issue, if you boot it through the gears while its faulting does it like hold back and not rev past 4.5k ? Mine did, put a genuine temp sensor in it hasn't faulted once!, it was reading so thing like -36 in measured values the  Gsf  "bosh" sensor