Cloud of Diesel when starting the car

[Andrewcupra TDI]

mine starts as soon as , i put the key in , if you blinked 'ud miss the glow plug light , it goes out quicker than the other lights

 

[meckanix]

Is the car ever left for long periods of time or is it driven every day?

It's driven at least 3 times per day. 1 to the office, possibly out for lunch and the back home again.

Also it does get long runs 30+ miles at least once a week

 

[meckanix]

I think your glow plugs are shot. Either the plugs themselves (more than one, perhaps all four) or the relay. Can you work with a multimeter, to find out if they are getting voltage? Procedure is, remove connector to engine coolant temperature sensor (simulates a stone-cold engine), detach electrical connection to glowplug, attach test leads to measure voltage at the glowplug connection, switch on ignition. Glowplugs should get +12v for 20 seconds.

I'd be really p***ed off if it is the glows, as they've just been changed at the 70k service (apparently they were still the originals before that) and the relay was tested along with the EMC. It got some serious TLC on the service, as I know the guys and I saw them do some really good work.

 

[meckanix]

Today's update

Weather / Temp
Rain and damp. Temp between 5 - 10*c

Morning Start
About 7am. Fine fired straight away

Lunch Time
About 12:30pm. Struggled to start and a rather large could was produced. The car was on a very, very slight slope with the rear of the car at the lowest point.
On the return leg the car turned first time

Home Time
About 4pm. Fired first time

 

[Markyboyt]

It's driven at least 3 times per day. 1 to the office, possibly out for lunch and the back home again.

Also it does get long runs 30+ miles at least once a week

I was going to suggest it could possibly be the battery losing charge overnight making it sluggish in the morning but the post above this one rules that out

 

[meckanix]

I was going to suggest it could possibly be the battery losing charge overnight making it sluggish in the morning but the post above this one rules that out

I never thought of that. I can still check it's charge nevertheless.

 

[Seat Adam]

Glow plugs only heat up for about 10seconds max. After that they switch off. As soon as the light goes out, start the engine as they will be cooling down. Suggest changing the glow plugs if they don't warm up too well. In your owners manual, it mentions starting and if I remember correctly, they are not really needed over 5 degrees, I still let mine warm up though. Obviously, the warmer the engine temp, the shorter the glow plug warm up time.
If you are checking the glow plugs, take them out and do a resistance check with a multimeter. Put one probe on the connector at the top of the glow plug and one where it earths on the screw thread. The resistance should be no more than 5 ohms.

 

[meckanix]

Right, well I can't get to the bottom of this. The car has been left for 6 days whilst I was away and straight away it was difficult to start, both in the morning and evening.

Now to be fair it had been cold today (5*c and under), but nevertheless its started fine at lower temperatures before now

I'm going to have to chalk this one up to experience and see what happens on warmer days, as either way I'm getting 550 - 600 miles from a full tank even when it does this, so as long as no damage is being caused I'm just going to have to live with it

 

[meckanix]

Glow plugs only heat up for about 10seconds max. After that they switch off. As soon as the light goes out, start the engine as they will be cooling down. Suggest changing the glow plugs if they don't warm up too well. In your owners manual, it mentions starting and if I remember correctly, they are not really needed over 5 degrees, I still let mine warm up though. Obviously, the warmer the engine temp, the shorter the glow plug warm up time.
If you are checking the glow plugs, take them out and do a resistance check with a multimeter. Put one probe on the connector at the top of the glow plug and one where it earths on the screw thread. The resistance should be no more than 5 ohms.

Just an FYI, they're new plugs and they were all tested when they were put in

 

[martincloud9]

Mine has had this issue for months now. I have had the glow plugs changed checked, and checked again. The coolant sensor changed and checked. I have had the seals changed on the fuel filter. I have used the vag-com to check for faults, none. Timing (on a PD) fine. The warmer weather makes it better, but not great.

This all started when I had to have the cylinder head replaced when the cam wore through a tappet. Before all of this all was fine and it always always started fine.

The only thing suspicious was the fuel temp sensor was saying warmer than any other temp by about 7-10 degrees.
Would having the fuel temp sensor reading wrong produce an incorrect mixture?
Does anyone know where I could find info on: for example, if this sensor readings change here it produces this result here (or a diagnostic to that effect)?

 

[irmscher2007]

I have been reading this with interest.

This is my 2nd Leon, it being a PD150, the first was a 110tdi and got it at 60k sold at 100k and it never missed a beat!

This car seems to struggle to start, but never fails to start and as you say, MECHANIX mine also has a cloud of dark smoke on start up. It blows past the car to the front. Not loads but its noticible

Driving dow the road with the cold engine, minding the revs theres white smoke from the exhuast which seems to blow onto the back window and steams the outside up. And then after a couple of miles the white smoke goes.

Once warm I dont see any smoke from the exhaust except if accelerating hard, but mothing major, just seems to be the usual diesel puff.

Can anyone suggest why theres a cloud of smoke on start up. I'm sure my old leon didnt do this.

 

[irmscher2007]

I've had a search on the forums regarding glow plugs, and I'm going to have a go at solving the excess smoke and slight struggling from the engine when starting from cold, with fitting a new set of glow plugs.

It seems easy enough to do, just need to take engine cover and harness off and use a socket to take the old ones out. Hopefully it'll start easier and wont be as smelly!