TDI - cold start valve

[pjbplumbing@bigpond.com]

Hi ya,
My TDI T4 2.5 seems to be running in the "Cold-start" mode 100% of the time, when starting the mtr when hot, it catches with a rev and excess smoke from the exhaust, then mostly idles at around 950rpm.
Anyone know where the sender is for this valve?
I assume it maybe stuck in either high or low resistance?
Any takers?
Peter

[gldgti]

sorry, no idea.....

[jets]

As there has been no response from this forum, can I suggest to post on www.brick-yard.co.uk. under T4 Technical [you will need to register first]
Simon Baxter, who runs that forum is a mechanic who works on T4s all the time. I'm sure he will know the answer.

[pjbplumbing@bigpond.com]

I found the problem.
Took the van to local spanner and he connected his multi-vehicle "hammer" (diagnogistic) electronic thingame, and confirmed the problem was a failed sensor on the coolant.
With this sensor dead, ecu thought motor was always cold, therefore always ran fuel mixture at a higher rate - like a cold start, or choke on an old carby engine.
I swapped the sensor over today, its part # V059919501A.
Cost $ 62.81
Time to install, 5 minutes if you haven't a bull bar on the front; you need to pull the front radiator panel out and forward to get to the sensor.
Sensor is held in place with a large plastic U clip - which dissappeared on me when I pulled it out - so I made a new one with 4mm Stainless steel welding wire.
Took the van for a drive - perfect!
Even the bentely workshop manual leaves this sensor out?
I've stuck 2 photos in for referance.
Peter

[cetane]

Thanks, mate! Contributions like that make forums like this a valuable place to be.

[jets]

Yes, thanks for coming back to us with the solution so we can all learn.
Was the new sensor the same colour? On the American sites they often refer to green sensors replacing black ones? BTW great pictures, are they of the old or new sensor? Looks like the old one to me.