Glo-plug warning light

JohnD · Post by **JohnD** » 27 Oct 2002, 00:41

My daughter has recently changed her diesel 205 for a Xsara HDI. Although the engine aways starts immediately, there is never any pre-heat warning light showing. She mentioned it when it went back to the dealer for it's first service and was told that the warning lamp wouldn't show until the weather was colder. She's already had to de-ice the windscreen, but still no pre-heat light. Can anyone confirm that everything is in order?

pwatson · Post by **pwatson** » 27 Oct 2002, 01:22

John,
Was puzzled by exactly the same thing on our Xantia HDi - but it appears it is normal. Glowplugs these days apparently take no time to heat up. By the way - exactly same on a LDV minibus I drove recently - kept looking for glowplug light on that too and it never appeared.
PhilW
P.S. See you on Go-touring.com!!
Phil

mg46783 · Post by **mg46783** » 27 Oct 2002, 04:09

HIya.... It IS right - to a point .. The system in use is such that there is no glow light.. I think you may find, again, depending on engine , that indeed it doesnt have any glowplugs!! Direct Injection.. So, you will never see a light - and it "should" - hopefully always start for her !!

JohnD · Post by **JohnD** » 27 Oct 2002, 13:41

Many thanks for your help - your input will be most appreciated.

Post by **RichardW** » 28 Oct 2002, 16:10

I am pretty sure they stillhave glow plugs, but they are the ceramic type that heat up in a few 10ths of a second rather than a few seconds, and a direct injection engine is much easier to start than an indirect one, hence the apparent lack of a light - I suspect it would come on if really cold, but then only maybe for 1s or so.
Richard

mbunting · Post by **mbunting** » 28 Oct 2002, 22:21

If you think about it, with a DI engine, you only need to heat the cylinder a little to get it warm enough for the first bang.
Once this has happened, the cylinder is warm enough to continue.
With IDI engines, the combustion took place mainly away from the area of the glowplugs - ie. in the pre-combustion chamber.
Incidentally, the VW's activate thier glowplugs when you open the drivers door, that way there is no 'delay' when you turn the ignition.
I don't know how it would cope with opening the door ten times on a cold morning without starting the engine though - flat battery ?

mg46783 · Post by **mg46783** » 29 Oct 2002, 05:24

hiya.... quote:Incidentally, the VW's activate thier glowplugs when you open the drivers door, that way there is no 'delay' when you turn the ignition.
I don't know how it would cope with opening the door ten times on a cold morning without starting the engine though - flat battery ?
unquote.<<<
Thats a really interesting point - I hadnt thought of that!! What about too if its a family of 10 or so, doors opening and shutting for half an hour before the "family" get going ??!! Bet versprungdertekneek people didnt think of that !<ggggg>

mbunting · Post by **mbunting** » 29 Oct 2002, 14:35

Slightly off-topic, but slightly related :
I was following a C5 in the rain this morning, still not very light yet.
The auto wipers were going about thier business.
The auto headlamps were constantly turning themselves on and off every few minutes.
I would have thought a delay timer would be used, and intelligence that if your windscreen wipers are going, perhaps side-lights should be on, and if the wipers are going full pelt, headlights should be used.
Didn't seem to be that intelligent though <img src=icon_smile_sleepy.gif border=0 align=middle>

Chris_L · Post by **Chris_L** » 29 Oct 2002, 18:48

Hi all,
This post is an interesting read. I'm especially interested about the VW mechanism and had a thought about it... As RichardW said, with DI engines, the glowplugs only need to be on for a few 1/10ths of seconds, so even if the door opened and closed half a dozen times then this would probably still be ok and not sink that much current. They may also have introduced a temperature sensor into the cylinder(s) so that the cold start mechanism doesn't re-initiate unnecessarily. One more thought.... the family getting in scenario - it makes no difference because they've probably just designed it to trigger on the drivers door opening. All in all, an excellent idea I think.
As for the C5 lights, that's an interesting one. I would've thought that the switching of the lights was all controlled by the engine management chip (and incidentally can you over-ride the default setting decided by the car?). It seems to just be a bit of an oversight on Citroen's part. It would be really easy simply to implement an additional low-pass open-loop filter which would effectively do a moving average of the light intensity over a certain period and switch the lights accordingly. The only thing you'd have to make sure of is that you had an over-ride if the light intensity changed very quickly (eg going into / coming out of a tunnel) to ensure that you don't have to wait the length of the filter (or averaging period) before the switch occurred.
Chris

mg46783 · Post by **mg46783** » 31 Oct 2002, 05:29

>>>One more thought.... the family getting in scenario - it makes no difference because they've probably just designed it to trigger on the drivers door opening. <<<
...... "that" was meant to be a joke ! <img src=icon_smile_big.gif border=0 align=middle>

volcane305 · Post by **volcane305** » 01 Nov 2002, 05:16

personally I would hate to have autoheadlights or autowipers. But one point on lights I think if lights are needed you should put them on not use side lights which are of no value whatsoever. If anyone disagrees just note how much more visible cars are with lights on compared to those with sidelights at any time of the day. It drives me crazy to be continually confronted in heavy rain with cars with no lights. In some ways drivers with sidelights only are more foolish they know they should have lights on but don't put them on!!
rant rant rant

Rune Rodahl · Post by **Rune Rodahl** » 07 Nov 2002, 19:10

Quote: <<If anyone disagrees just note how much more visible cars are with lights on compared to those with sidelights at any time of the day. It drives me crazy to be continually confronted in heavy rain with cars with no lights. In some ways drivers with sidelights only are more foolish they know they should have lights on but don't put them on!!>>
I live in Norway, and for the last 15 years the law has said "on at all times- when vechile is moving" It is VERY difficult to say if an oncoming car is actually oncoming or parked - if this vechile has no driving (head) lights. Therefore every car imported to norway must have automatic driving light - and I'm glad that is the case!
I have been driving in France, Italy, Ireland, Sweden - and I must say I am surprised that only Norway - to my knowledge, has automatic driving lights!
In aviation there is a saying that adopts to this:
SEE AND BE SEEN !!!