Octavia mk1 (2002) TDi 110bhp, which if the engine is cold (ie. car not used for say 6+ hours) will be hard to start (ie. choke / splutter into life) and produce a fair amount of white smoke (no black or blue, just white).

if the engine is hot, then it starts instantly with no problems at all, all healthy (no hesitation, no smoke).

so whats going on?

I know that the EGR valve about 3 weeks ago was sticking shut and preventing the engine starting at all, whilst sounding like the engine had no compression. The AA man removed the EGR valve and cleaned it with carb cleaner, removing tons of black sludge.

Now though, it does start, just with difficulty, where as the time it wouldnt start, the EGR valve just got stuck one day after being fine for 110k miles! So the behaviour now is different from before.

Is this the same sticky/dirty EGR issue again? The behaviour seems different and I'm not so sure.

Thanks

EGR sticking (it includes the anti shudder valve) or glow plugs failed/failing. This can be the glow plugs, or the glow plug control relay, or glow plug fuse.

would the glow plugs even be needed in summer? the glow plug light comes on for say 1 second and pops off again.

I will get the EGR and inlet manifold removed and cleaned and see if it improves, I hope so!

What about CTS? could that not be faulty?

Sarah

I'd suggest if you have not changed your fuel filter you do that or at least drain the water from it as that may well be where your white smoke is coming from.

If your car has gone over 80k miles and you've not put new glow plugs in this is also worth doing.

The EGR can be cleaned or replaced if proving to be problematic but it's also worth cleaning the pipework to it, the engine breather system and the intercooler system properly too. This should remove oily sludge from the whole system and reduce future problems.

Another thing worth doing to reduce deposits in the systems is to change your air filter at every service (well 10-20k mile intervals anyway) as they are blocked solid by the time the official interval is up.

HTH

I had cold starting problems that were caused by the timing on the fuel pump being waaaaayyy to retarded, no problems to start when hot but a pain when cold.

Have you had the cam belt replaced recently?

I've got the same thing but my cam belt and fuel filter were recently changed, and it was ok after the change of belt, so I don't think this is the problem. I have also got a hesitation from start up that disappears until i get revs over 2500, and then it is gone for the rest of the journey, unless i switch off and then it's back straight away. I thought it was the maf sensor, so i will try changing that soon

cambelt was done in January and I had no problems or smoke etc starting since then until recently (May). So I think the timing is OK. I only have the 3rd party VAGCOM so I cannot check it.

Air and fuel filter were changed in September by the previous owner. I spoke to the garage that did it and they said it was a normal service, but couldnt really be definitive on what was done. Oil and filter change was done then and again this week by me. Glow plugs I have no idea if or when they have been changed.

There could be water in the fuel filter I guess - I will check.

What is the CTS? Sorry, google just gives me cadilacs lol

The hesitation is only in starting, after 5 seconds everything is as normal, though there is a small cloud of smoke that then dissipates. It is literally the turning over and starting that is funny, so I wonder about the timing as I know that the ECU dynamicly alters the timing after a couple of seconds, but at start up it is fixed manually on the pump.

CTS = coolant temperature sensor, original part is grey, revised version is green, it's located on the passenger side of the engine where there are a load of pipes which go to the radiator.

Your problem sounds similar to mine when the glow plugs were knackered, it's like it's only starting on 2 or 3 cylinders and eventually all 4 get going. Could be worth changing the glow plugs, it's no different to changing spark plugs and a set cost me £30 odd from GSF, but how much they do for starting in warm weather I'm not sure.

The ECU can adjust the timing but only within certain limits, mine was way to far out for the ECU to compensate for. I had my cam belt done in May time but didn't really notice the problem until the weather got cold.

re: cambelt, if the timing was out i would have likely have had starting issues in January / February rather than May onwards when the weather is warmer. So, I assume timing is ok.

glow plugs should show a warning light shouldnt they? And also, im not sure how much they even do anything in summer, but as I dont know when they were changed they could be duff.

When my EGR valve was stuck shut (i.e. no air getting into the car) a month ago, the AA guy removed and cleaned it with carb cleaner, it was fine for 2 weeks, but then started with the smokey difficult start ups.

He checked the CTS on his laptop with the car running and he said the coolant temp sensor was working fine, so unless it broke this month, it should be fine.

The CTS will only throw an error when it gives completely silly readings, it can give a reading which is wrong but within the correct range without an error. On my car this resulted in it idling too quick and also sort of over revving on starting, both when warm.

Just thinking out loud but if the CTS is bust and is telling the ECU it's colder than it is then too much fuel could be chucked into the cylinders, or would that give you black smoke? Try unplugging the CTS and see what happens - the glow plugs will come on for about 20 secs IIRC.

I think the glow plugs will cause an error if they don't work at all, or are disconnected, but otherwise won't show anything. Basically they work but don't heat up enough to actually help start the car when they are knackered.

Or is the EGR partially stuck? You could take the pipe off that goes into the EGR from the intercooler and have a look at the EGR valve.

I have changed the glow plugs and still have the slow, white smokey cold starts.

I have not yet checked the glow plug relays and fuse, where are they (please be as accurate as you can be!)

I have drained the fuel filter as well.

Where precisely is the CTS (a picture would be awesome!)?

Any other suggestions?

the glow plug relay is behind the dash below the steering wheel, you can get at it by remove the panel on the underside of the dash above the pedals and looking upwards, helpfully the relay has 109 stamped on it in big black letters.

The CTS is on the right hand side of the engine - circled on the attached picture. You can just make out I have the revised green version