Cold Starting

[Mike]

I've just replaced a cylinder head on my S2 16v i.e. and the cold starting has become a real struggle.

The engine requires 10-15 secs of cranking on the starter before it fires (with lots of smoke). Once running it is lumpy and sounds like it is missing, but after a few minutes this clears.

When warm, the engine is very smooth and there is NO evidence of a mis-fire, oil burning, fuel starvation or timing problems.

I have changed the HT leads to no effect, but suspect that it may be a problem with the Air By-pass valve(choke). Has anyone experience of the symptoms of this failing?

When changing the HT leads I did notice that there was corrosion on the No.3 coil terminal, but this has been cleaned.

[kassus]

hi,

i think you are lucky man, because the problem is knwon, and you must search for problems in the cylinder head change, maybe the vavles are timed out and causes an explosion failure (open closed) or something similar

best regards and lucky !

[Mike]

Problem Solved.

Checked out the air bypass valve and it was functioning normally i.e. open when cold and closing off when warmed.

Solution was the replacement of the engine coolant temperature sensor on the Thermostat with the one fitted to the original cylinder head. Cold starting is now much more rapid and almost instant when ambient temperature is less than 5 Centigrade.

For anyone not familiar with the sensor, it is the one mounted horizontally into the Thermostat at the rear of the Thermostat casing. In my case it had a blue plastic connector block.

[kassus]

Hi Mike,

Congratulations for solve your problem, i also have problems with my thermostat. Now i have some questions for your:

1.are you happy with the performance of the 2.0 16v (i also have a S2) ?2.i feel the engine so noisy in full acceleration, it is not?
3.did you pass from 5.000 rpm in 5º easy, i just see 220 twice

Thanks, and visit www.devoted.to/lanciathema