Cold Start problems with a PD TDI 170

[Jane_i10]

Hmmm, lots of people complaining of repeated DPF regens since the injector change, although they seems to reduce over time...

Yeah my light come on last night, people dont half give you funny looks when you driving round town revving its tits off

Like i said before it could be something completely simple like the fuel being too cold or even the rubber seals swelling.

[silver1011]

Intresting read

Winter Diesel

I use BP fuel mostly, although I have filled up with Sainsbury's fuel recently. I'll keep using BP to see if I can notice an improvement.

[KenONeill]

Well, there has been some right bollards talked in this thread and no mistake!!

1) All diesels run lean on part-throttle!

2) Black smoke is unburnt carbon, which appears when you're running rich!

3) If your glowplugs are playing up, you'll get a puff of white (some say pale grey) smoke from the exhaust on a cold start, and this will smell of diesel fuel. Also, the engine might well start on 2 or 3 cylinders and run rough for a few seconds.

4) EJ's Dad's old Merc would have had pre-combustion chambers unlike the VAG 1.9 and 2.0TDi engines, and this is largely why it needed longer pre-heating.

5) Just because the light goes out doesn't mean that the glowplugs are off yet.

6) If you want to test glowplugs further than (3), use a voltmeter!

7) These engines don't use glowplugs above 7C.

[Jane_i10]

Well, there has been some right bollards talked in this thread and no mistake!!

1) All diesels run lean on part-throttle!

2) Black smoke is unburnt carbon, which appears when you're running rich!

3) If your glowplugs are playing up, you'll get a puff of white (some say pale grey) smoke from the exhaust on a cold start, and this will smell of diesel fuel. Also, the engine might well start on 2 or 3 cylinders and run rough for a few seconds.

4) EJ's Dad's old Merc would have had pre-combustion chambers unlike the VAG 1.9 and 2.0TDi engines, and this is largely why it needed longer pre-heating.

5) Just because the light goes out doesn't mean that the glowplugs are off yet.

6) If you want to test glowplugs further than (3), use a voltmeter!

7) These engines don't use glowplugs above 7C.

Sorry yes you are right, black is running rich!

But on start up even on idle any engine will throw in more fuel then what is needed

Iv been told the glowplugs dont work untill 3 degrees or less

This could explain my engine kangerooing though, if these injectors (or something along the fuel delivery system) is not playing ball but im not convinced.

[KenONeill]

Sorry yes you are right, black is running rich!

But on start up even on idle any engine will throw in more fuel then what is needed

Iv been told the glowplugs dont work untill 3 degrees or less

This could explain my engine kangerooing though, if these injectors (or something along the fuel delivery system) is not playing ball but im not convinced.

I've no idea about what's wrong with these 2.0TDi170s either. I'm sort of suspecting a mapping issue; does it mostly happen when you're rolling back on power after slowing on a closed throttle?

Also wildly o/t, but I've seen a tuned Mitsu Evo do black smoke when the driver hit full throttle at low revs alongside me.

[Jane_i10]

I've no idea about what's wrong with these 2.0TDi170s either. I'm sort of suspecting a mapping issue; does it mostly happen when you're rolling back on power after slowing on a closed throttle?

Also wildly o/t, but I've seen a tuned Mitsu Evo do black smoke when the driver hit full throttle at low revs alongside me.

Actually its the other way round, when its under heavy acceleration i.e over taking someone, it will lurch forward and then all power will drop of a split second then full power again :S asif something is blocking fuel delivery

[rsbspt]

Actually its the other way round, when its under heavy acceleration i.e over taking someone, it will lurch forward and then all power will drop of a split second then full power again :S asif something is blocking fuel delivery

We're getting way off topic here. This thread is to try to find a cure for the 'first start on a cold morning' problem.

[Jane_i10]

We're getting way off topic here. This thread is to try to find a cure for the 'first start on a cold morning' problem.

Well yes and no, it could be related..its all one big mystery

[KenONeill]

Actually its the other way round, when its under heavy acceleration i.e over taking someone, it will lurch forward and then all power will drop of a split second then full power again :S as if something is blocking fuel delivery

Is this consistant behaviour? A surge like that makes me think of a number of possibilities. In no particular order:-

1) Fuel starvation - suspect blocked filter or problem with pump.

2) Mapping issue on sudden high demand.

3) Kick from traction control (ASR or ESP systems), particularly if it only does it in the wet and/or uphill.

4) Vacumn hose starting to break down. These are bu99er$ to find, but start by squeezing any of VAG's beloved external fabric armoured hoses, and replace them if they're squishy because that indicates the rubber coming away from the fabric so they collapse under high vacumn.

[Jane_i10]

Is this consistant behaviour? A surge like that makes me think of a number of possibilities. In no particular order:-

1) Fuel starvation - suspect blocked filter or problem with pump.

2) Mapping issue on sudden high demand.

3) Kick from traction control (ASR or ESP systems), particularly if it only does it in the wet and/or uphill.

4) Vacumn hose starting to break down. These are bu99er$ to find, but start by squeezing any of VAG's beloved external fabric armoured hoses, and replace them if they're squishy because that indicates the rubber coming away from the fabric so they collapse under high vacumn.

The funny thing is, its not constant behavior and when i try to recreate to try and diagnose it sometimes it will not do it and accelerate fine, other times it will have a little spat and then theres times were its like riding a mechanical bull, this is why im guessing it down to the map software (just had it remapped not so long ago and im going to give it the benefit of the doubt for a few miles to let it configure itself)

Wouldt a split in a vacuum hose cause it to run slightly lean? (a car i worked on before had a split vacuum hose and this fed into the inlet manifold, causing ambient air to get in)

[markyvrs]

Re: Cold start

Have you tried waiting at least 10 secconds AFTER the glow plug light has gone out before starting?

Mine starts with a bit more conviction when I do this.

[Jane_i10]

Re: Cold start

Have you tried waiting at least 10 secconds AFTER the glow plug light has gone out before starting?

Mine starts with a bit more conviction when I do this.

Thats a tad bit long dont you think? once the lights come of the dash i crank mine about 2-3 seconds after

[silver1011]

I thought that the light turning off was a sign that the glow plugs have finished heating up, the longer you leave starting the engine the cooler they'll be?

Either way, I'm up for trying anything! I tried cycling the glow plugs (ignition on / off / on / off) but this made no difference so I'll give this a try too!

[nick74]

I thought that the light turning off was a sign that the glow plugs have finished heating up, the longer you leave starting the engine the cooler they'll be?

Either way, I'm up for trying anything! I tried cycling the glow plugs (ignition on / off / on / off) but this made no difference so I'll give this a try too!

On some cars (eg oldschool Pug 1.9 diesels) the glowplugs themselves used to stay on for some seconds after the glow plug light had gone out. On VAG diesels this doesn't seem to be the case and the glowplugs lose power and start cooling the second the glowplug light goes out. In cold weather I can tell when the glow plugs have switched off on mine as the interior lights get slightly brighter!

[KenONeill]

The funny thing is, its not constant behavior and when i try to recreate to try and diagnose it sometimes it will not do it and accelerate fine, other times it will have a little spat and then theres times were its like riding a mechanical bull, this is why im guessing it down to the map software (just had it remapped not so long ago and im going to give it the benefit of the doubt for a few miles to let it configure itself)

This makes me think that (3) sounds most likely, particularly if you have ESP so don't get a warning light like the ASR system will give you.

Wouldt a split in a vacuum hose cause it to run slightly lean? (a car i worked on before had a split vacuum hose and this fed into the inlet manifold, causing ambient air to get in)

These hoses aren't split; they're a soft rubber tube like an inner tube, and a woven (sp) fabric sheath like a braided stainless brake pipe glued over it. The glue fails, so the hose closes under high vacumn, but looks normal when the engine's off or idling.

Also O/T, but can I say that it's a pleasure to talk to a pretty girl who'll get her hands dirty when her car's not right rather than just batting her eyelashes at the first man she sees after it actually breaks?

[Jane_i10]

This makes me think that (3) sounds most likely, particularly if you have ESP so don't get a warning light like the ASR system will give you.

These hoses aren't split; they're a soft rubber tube like an inner tube, and a woven (sp) fabric sheath like a braided stainless brake pipe glued over it. The glue fails, so the hose closes under high vacumn, but looks normal when the engine's off or idling.

Also O/T, but can I say that it's a pleasure to talk to a pretty girl who'll get her hands dirty when her car's not right rather than just batting her eyelashes at the first man she sees after it actually breaks?

Yeah i have the ESP, it will also feel jerky round town at time, like them chips you can buy yourself and plug in (having an adjustable setting to suit the driver)

I dont mind getting my hands dirty at all, in fact i love working my cars but im never taken seriously when i get stuck and need help

This was mine this morning, not a bad start actually but it was +2 degrees and still very lumpy

http://s17.photobucket.com/albums/b77/xXDODGEXx/?action=view&current=Coldstart2.mp4

[whizzmista]

hi there i had the same car as yourself blubblec when it was minus 19 and started fine so i would check the glowplugs, how long does it take for the light to go off? i now hv a 2007 vrsd l&k which gets lumpy when the oil and fuel filter hasnt been changed!!!

[whizzmista]

ema jane u never let the glowplugs warm up

[Jane_i10]

ema jane u never let the glowplugs warm up

The light goes out, i turn the key. The way i figured the light is only on when glow plug are working, when above about 4 degrees the glow plug dont fire up but the light still comes on but when i have my Mk4 Golf PD once it was -9 degrees and the light stayed on twice as long, giving the impression that once the light has gone out the plugs have done their work

[Davidsr20]

Actually its the other way round, when its under heavy acceleration i.e over taking someone, it will lurch forward and then all power will drop of a split second then full power again :S asif something is blocking fuel delivery

Mine does this too and then shortly after the dpf light comes on,maybe it's something to do with regene! My car has a faulty exhaust pressure sensor , iv ordered the new type one and having it coded tomorrow hopefully.

[KenONeill]

Yeah i have the ESP, it will also feel jerky round town at time, like them chips you can buy yourself and plug in (having an adjustable setting to suit the driver)

I dont mind getting my hands dirty at all, in fact i love working my cars but im never taken seriously when i get stuck and need help

This was mine this morning, not a bad start actually but it was +2 degrees and still very lumpy

http://s17.photobucket.com/albums/b77/xXDODGEXx/?action=view&current=Coldstart2.mp4

And this now points to 2 separate issues:-

The roughness suggests over-fuelling to the extent of putting the fire out, but that should be smokey. Since it's not consistent, that suggests a dodgy sensor that doesn't throw a fault code.

The roughness on starting can surely only be the ambient tenperature sensor (check readings in whatever combo of Climatronic, VAG computer, Bluefin etc you've got are plausible), glowplugs or glowplug control box?

[Jane_i10]

And this now points to 2 separate issues:-

The roughness suggests over-fuelling to the extent of putting the fire out, but that should be smokey. Since it's not consistent, that suggests a dodgy sensor that doesn't throw a fault code.

The roughness on starting can surely only be the ambient tenperature sensor (check readings in whatever combo of Climatronic, VAG computer, Bluefin etc you've got are plausible), glowplugs or glowplug control box?

Well its got a DPF on so that will stop any smoke been emitted wont it?

To be honest that was a good start, normally it cranks for a few seconds and then fires into life with a lumpy fashion.

Its been on a fault code reader a few times now and nothing has been flagged up this is why im trying to get back to basics with this problem as the vagcom seems to be no use.

What kind of sensors dont throw up a fault code? (i thought they all did)

Basically all i want is like a bullet point list of what readings the car takes from which every sensors before i turn the key i.e coolent temp sensor, cold start sensors ect ect so we can start eliminating one untill the offending sensor (or whatever it is) is found

[silver1011]

This problem isn't injector or glow plug related. I've managed to determine that one myself through several dealer visits.

There are also no faults ever logged so this backs up the fact it isn't the glow plugs as these are monitored and would throw up a fault it there was a problem.

Even so mine were removed, examined and photo's sent to Skoda UK - all came back and confirmed all OK. Also another member who posted previously swapped out the glow plugs again with no effect.

Ema, that would be a good start-up for me, add another 3-4 seconds of cranking and you'll be close. It would be great if you could take it back to the dealers as I use the same one as you, having someone else on their books with the same fault would help my case

[Jane_i10]

This problem isn't injector or glow plug related. I've managed to determine that one myself through several dealer visits.

There are also no faults ever logged so this backs up the fact it isn't the glow plugs as these are monitored and would throw up a fault it there was a problem.

Even so mine were removed, examined and photo's sent to Skoda UK - all came back and confirmed all OK. Also another member who posted previously swapped out the glow plugs again with no effect.

Ema, that would be a good start-up for me, add another 3-4 seconds of cranking and you'll be close. It would be great if you could take it back to the dealers as I use the same one as you, having someone else on their books with the same fault would help my case

Im pretty reluctant to take mine back to the dealers as mine has been remapped now and this will void my warranty. Yeah that was a good start for me aswell, normally a tad worse

[rsbspt]

hi there i had the same car as yourself blubblec when it was minus 19 and started fine so i would check the glowplugs, how long does it take for the light to go off? i now hv a 2007 vrsd l&k which gets lumpy when the oil and fuel filter hasnt been changed!!!

No it isn't the glow plugs. I've changed mine and it made no difference to the issue of poor starting in low temperatures.