Passat TDI 1998 AFN Dies when cold

**Elvis the king** · 01-06-2008,10:42 PM

Hi again folks
I thought my car would never die but its not running to well.

Start it up from cold and drive away its OK unless I give it to much throttle then it dies with loads of black smoke and it takes a few minutes to restart again. But once the temperature gets to normal I can floor it no problem its just when its cold.

Any ideas?

**Crasher** · 01-06-2008,10:46 PM

A fault code read first, possibly the coolant temperature sender.

**Elvis the king** · 01-06-2008,10:57 PM

Hi
Thanks for that, someone else did mention that.

I will put it on the scanner tomorrow.

**Elvis the king** · 01-06-2008,10:58 PM

But then why does it chuck out the black smoke and stall?
Is it over fueling?

**Crasher** · 01-06-2008,11:13 PM

If the coolant temp sender is telling the computer that the engine is at -40°c then it will over fuel just a bit but EGR problems can also cause this symptom. Whatever, a fault code read, print, clear, drive and re-read and print is the first thing to do, it helps prevent time and money wasting guess work.

**Elvis the king** · 02-06-2008,12:04 PM

Just an up date.
I scanned it this morning, nothing came up, cleared it re-scanned still nothing. As the temperature got to about 33 degrees I revved it hard the usual happened it ran lumpy smoked a lot and died (tried to keep it running) managed to restart it and I noticed the temperature reading on the scanner was -40 (spot on there Crasher :-) ) but the reading on the dash was about 30 ish. I gave some light revs and she ran smooth and the scanner reading then went to 65 degrees and she then runs OK. Once warmed up she runs fine.
looks like you were right Mr Crasher. Thank you.
I will let it cool down and give it another scan but I will probably invest in a temp sender.

**Elvis the king** · 02-06-2008,01:20 PM

more up date.

Tested the temp sender unit with the meter as per autodata. all ok.
I tried running the motor with it disconected but no different.
back to square one...

**Crasher** · 02-06-2008,01:36 PM

Change the sensor and see how it goes. If you keep the revs down, does it drive OK and then rev properly when hot? It is difficult to start again after the cut out, sounding different to how it normally sounds when being cranked over?

**Elvis the king** · 02-06-2008,05:39 PM

Change the sensor and see how it goes. If you keep the revs down, does it drive OK and then rev properly when hot? It is difficult to start again after the cut out, sounding different to how it normally sounds when being cranked over?

Thats spot on there. all of the above