My Y-plate Fabia 1.4 16V won’t start when warm. I have read through quite a few posts on the site that cover this, but would appreciate comments on my own diagnosis.

To cut a long story short - when warm it turns over but takes ages to catch, when it does start to fire it takes a while to stabilise. Also sometimes when idling the revs race from 500-1000rpm without me touching the throttle pedal.

I found a split servo hose (I get the impression this is reasonably common with Skodas) so it was replaced. Also the EGR valve was replaced as it was coked up.

So I thought I had cracked it – split hose – too much air in the mixture – ECU pumps more fuel in causing a rich mixture – engine wont start because it’s flooded.

When I drove it after the hose and EGR valve was replaced, it was sweet, it ran so well and seemed to go faster and smoother since I had an oil & filter change done at the same time.

Now two days later we’re back to square one with a warm start problem, so I am trying to think logically about what may be the cause. The most common (and cost-effective if it works) course of action seems to be to change the coolant temp sensor, as it may be sending wrong info to the ECU.

Any comments would be welcome before I set out to buy a new sensor. The EM light is on as well, but I haven’t had the codes read yet.

Finally, not sure if this is related or indeed relevant to this situation, but it burns more oil than the 1L/1000km the book says.

Thanks in advance

Check for blue smoke from the exhaust, if there is possibility you could have worn piston rings

Thanks Chris, I haven't noticed the blue smoke from the exhaust, but if I open the oil filler cap when the engine is hot there is some smoke wafting out of the opening, so I thought it must be burning some oil.

Otherwise the car runs well and easily gives me 45-50mpg on a run

Would you think the oil buring issue is related to the warm start problem?

Might be the temperature sensor

Give the crankcase breather system a total clean out from top of block right through to air filter. May not help with the hot start (or may do), but could help with the oil consumption.

Thanks to all for your comments, very much appreciated, I will change the temp sensor and do as Kwacka says regarding the breather system - then report back with results.

Well, one week on and 950 miles covered, mainly motorway from Cornwall - Northampton - Rugby - Northampton -West London - Stansted - West London - Cornwall.

During the first 250 miles I was dreading getting caught in traffic in case the engine revs started racing, or worse still, stalled then wouldn't warm start with a 1/2 mile queue behind me.

I noticed for the first time since I've had the car the temp gauge was wavering; it normally sits on the half-way mark, nicely vertical.

The revs were a bit unsteady at lights/roundabouts, and I'm thinking in terms of having a new temp sensor fitted after my road trip.

But after reaching Northampton on the first day it was fine, it even started first time after I had stopped for 3 mins to get a bag of chips.

So far so good - except the car smells of chips.

The rest of the week has been uneventful: the car has started first time every time, hot or cold. I got an average mpg of 49, and it runs sweet. It had an engine flush with an oil and filter change last weekend and I was expecting to put at least a litre in after my trip, but it hasn't used a drop. Unbelievable, as if all it needed was a bit of exercise.

I think I may still have the sensor changed as sods law dictates that it will fail to start again one day in the future, most probably when it's VERY inconvenient.

These engines seem to be very senstive to a dirty crank breather system, I honestly think that some of the 'piston ring failures' may simply be clogged breather problems. I too have done the occasional engine flush, when we first bought the car at 48k miles it was using oil, now at 85k miles it hardly uses a drop.

Hope the temp sensor gets you fully sorted.