3 times in the last week my Skoda would not start on the first attempt. But after about 5 tries and about 5-8 minutes it started. Twice was cold at 5pm after coming out of work and once was when warmed up after driving home but stopping at the shop for 5 mins. Now its outside my house and it will not start at all. Plenty of power in the battery. It turns fast and no problem at all but will not fire. Possibly unrelated but there is a whirring sound sometimes just after the engine starts as if the starter motor or some similar wheel keep turning for 2-3 seconds after the engine starts. I think the clutch release bearing is on the way out. Thats probably unrelated to my starting problem. Sometimes when I try to start i get a repeated tome on the oil light flashes. There is plenty of oil in the car. It has 100k mls on the clock. There apears to be some kind of repair job done on the connector for the coolant temperature sensor on the coolant resivoir. Sometime athough the engine should be at full temp the temp light is ony 1 quarter way up. There is diesel in it too.

Please help. This car does 63mpg. :-)

Could be the anti shudder valve - this is the EGR valve as well

The sensor on the reservoir is just a low level sensor, the CTS is on the right side of the block on a pipe from the radiator.

Sometime athough the engine should be at full temp the temp light is ony 1 quarter way up. There is diesel in it too.

Please help. This car does 63mpg. :-)

Coolant temp sender is faulty. Very common failure.

Coolant temp sender is faulty. Very common failure.

I paid 37eur at my local Skoda dealer for a new coolant temperature sensor which I just fitted but still no ignition. :-(

Must try anti-shudder valve next. I assume I clean it rather than replace?

try unplugging the coolant temperature sensor, then try starting.

If it starts straight away everytime, then it points towards a strange quirk of the VAG diesels - for some reason, when the engine is "warm" (not sure how warm warm is, but maybe in this weather, at 5pm it may still be warm enough) fuel is not injected until the engine is cranking above 250rpm. This condition is not imposed when the engine is "cold", and unplugging the coolant sensor forces the system into seeing the temp as cold. The engine may sound like it's cranking fine, and often is, but not quite making the 250rpm.

The "fix" is to replace the starter motor evidently, which I guess just manages to turn that little bit faster - my guess is that a new battery may provide the same result for less cost

Thnaks for all your comments. I have done some more research and testing.

Check the egr. Its spring loaded open by default and when I close it i springs back open. Good?

Disconnected the electrical connectors from the new coolant temperature sensor. Tried to start. Result - exactly same as before, engine turns but no ignition.

Interesting point of note when the coolant temperature sensor is disconnected the glow plug lights do not come on. I have seen it flicker on 1 or 2 occasions when the temp sensor is connected.

I had to recharge the battery because it was running slightly low due to the cranking with no starts. Have read about the starter motor issues where the engine must crank at 250-300 rpm to work. The engine cranks really fast but I cant measure it. It was working fine last week. What suddenly changed. So I think the chances of being the starter are low.

The check engine light is not coming on either. ECU? Checked relay 109. Its black on this car not grey. Does that suggest its been replaced already or is the newer type and should be OK? When I turn the ignition key and put my hand on the relay I can feel the relay switching. Don't know if its operating as it should though.

Fuel seems to be moving through the clear fuel pipe at the top of the engine. There is usually a small air bubble in it which disappears after cranking.

You need to get it diagnosed with vagcom. Pointless throwing any more parts at it.

I had some problems with the 109 relay which meant the glow plug light didn't come on or didn't stay on long enough.

You do need to get someone to look at it with VCDS before changing any more bits. Though the 109 relay didn't throw up any errors.

When was the cam belt last changed by the way?

Had to call in the cavelry. Local mechanic that is. He said it was a dry solder on the fuse board. Cost me 100eur to get fixed.

Thanks for all your help.