Warming up time for Glow Plugs

Karl · Post by **Karl** » 09 Dec 2003, 16:36

How long should it take for the glow plugs to warm up form stone cold? Mine takes about 4-5 secs for the light to go off; is this normal. I know a VW TDi is almost Instantanious, whys that?

Post by **RichardW** » 09 Dec 2003, 18:03

Karl,
The Xantia TD is an 'old tech' indirect injection unit. This means it needs a lot of heating to get it started even when the ambient temp is quite high. VW TDi is direct injection and needs very little heat, even at low ambient temps. This is further compounded by the Cit using old tech metal glowplugs, whereas the VW will use latest tech ceramic plugs, which get to the same temp as the metal ones in around 1s, rather than 8s or so. I think it is possible to buy a new plug timer and the new plugs and retrofit this to the Xantia, but since the glow plug heating time is not that much longer than it takes to put your seatbelt on I wouldn't bother!

Karl · Post by **Karl** » 09 Dec 2003, 19:36

Thanks Richard at least I can now explain to fellow petrolheads why I`ll sitting there like a lemon for those few seconds.
Anyone tried putting in a plug timer or know were I can get one from, I suppose it links to when you open the divers door?

AndersDK · Post by **AndersDK** » 09 Dec 2003, 21:08

Karl -
4-5 seconds is FAST [:)]
Many first generation diesels takes up to 10seconds or more to make a first starter [:D]
Personally I would'nt bother fitting a special glow timer setting off by the door switch. It's a pretty heavy electrical rewiring job involved in this - taking your knowledge in car electrics to the limits.
For starters - have a look on the Czeck CCC site for the Xantia diesel wirings. Once you understand this - and all cabling recognised/located in YOUR particular Xantia model - then it may be time thinking mod's [;)]
http://citroeny.cz/servis/servis.htm (-> Xantia button -> electro scemata button)

sooty · Post by **sooty** » 10 Dec 2003, 02:50

You will find that the light on the dashboard going out in 3 to 7 seconds depending how cold the weather is, but the glow plugs will actually stay on glowing for approx. 1min to 1.5 mins.
If when you start your engine at any time, after a minute or so you will hear the engine note change. The revs will slightly jump up 20 to 50 rpm, just like when you switch off you headlights, or listen to the heater plug relay for when it clicks(turning off).
Sooty

mijyou · Post by **mijyou** » 10 Dec 2003, 03:47

Do the glow plugs have to be used even if the car is only stood for a few minutes?
Jim

AndersDK · Post by **AndersDK** » 10 Dec 2003, 06:18

Jim -
Should not be necessary - but engines are different - as to wear & others. Simply try learn how your engine behaves & wants it.

mijyou · Post by **mijyou** » 11 Dec 2003, 01:36

Thanks for the reply Anders.
I got told to use them everytime by the bloke who sold me the car, even though the car started no problem after a few mins.
Jim

jeremy · Post by **jeremy** » 11 Dec 2003, 03:31

Anders
Haven't you got to be a bit more careful of a diesel with a catalyst. I seem to remember being told to heat fully when i had a temporary job loading new cars onto ships.
I suppose the reason is this: If the engine doesn't start propmtly and on 4 cylinders some smoke is emitted which is white and is unburnt fuel simply pumped into the exhaust. Without a catalyst there is no problem but with a catalyst this unburnt fuel will get on to the catalyst. With luck it will burn away harmlessly when the engine gets hot but could cause damage if the car doesn't get hot enough.
Unfortaunately none of my diesel handbooks contemplates catalysts so I can't see if there are any warnings.
jeremy

AndersDK · Post by **AndersDK** » 11 Dec 2003, 05:21

Jeremy -
Can't argue against that [:I]
But I suspect the standard generation diesels with cat converters have some kind of glowtime LOCK - meaning the starter won't turn on the key - unless glowtime is satisfied. It would indeed be VERY simple to incorporate - using a relay working off the glow lamp output. Even worth retrofitting saving the life of the cat.
The later generation HDI (& derivatives) - does'nt really need a glowtime - except under severe (cold) start conditions.

Kowalski · Post by **Kowalski** » 11 Dec 2003, 17:26

The reason that you should always use your glowplugs is that the engine is more difficult to start without them which means you have to crank for longer taking more energy out of your batter. As you probably already know lead acid car batteries don't like being deep cycled. Your starter motor also gets hot when you crank for a long time so cranking without glowplugs means that it will have a hard (short) life too.
Direct injection diesels (such as PSAs HDI) do need glowplugs but they don't get used unless it is proper brass monkey weather and even then they don't afterglow like they do on an XUD...

NiSk · Post by **NiSk** » 11 Dec 2003, 18:47

The catalysts fitted to diesels are not nearly as sensitive to oil pollutiona as those fitted to petrol engined cars. The catalyst is a urether compound, not platinum, so don't worry about that.
//NiSk

sooty · Post by **sooty** » 13 Dec 2003, 00:15

Do the glow plugs have to be used even if the car is only stood for a few minutes?
Jim
--------------------------------------------------------------------------------
1992 ZX Avantage 1.9D
Once you switch on your ignition to start your engine, your heater plugs start thier timed cycle according to the weather like or lump it. You cannot choose, whether to have then on or not, only if you a switching device of some kind to turn the relay on or off.
But as Kowalski says, by turning them off, you will find it difficult to start and ruin your battery in time.
Best to leave well alone??
Sooty

oilyspanner · Post by **oilyspanner** » 14 Dec 2003, 18:11

Intersting topic, my old non turbo XUD motors would always start without heat even if they were remotely warm, eg after standing for four hours or so. But my turbo ones will not start easily without glowplug assistance even when hot! At first I thought it was wear or low compression, I asked around and it seems that its a characteristic rather than a fault, I use the waiting time to fit the front of my stereo, set volume and station, belt up and by then Im ready. Its only a few seconds, and on my BX it is followed by a few seconds wait while the car gets up anyway, I also like the idea of a few seconds enforced idling after a cold start "To let the oil get around" Patience is a virtue
Stewart

mijyou · Post by **mijyou** » 15 Dec 2003, 00:11

My car is the XUD non turbo which will start no problem after been stopped for quite awhile.
I don’t mind waiting for the few the secs it takes to warm them up, but just wondered if it was necessary if it starts ok.
After all the differing opinions i think i will use them just to be on the safe side.
Thanks Jim