Cannot see clearly because of smoke during cold start

[CPtje]

Hi,

Just as an introduction, I am Dutch, normally driving on the right hand side, except when visiting the UK with my French camping car on a Fiat Ducato chassis having a Peugeot 1.9TD XUD9 engine (2001) and a Bosch injection pump. This latter information I have figured out until now by reading through this forum.
I read a lot and i'm puzzled a lot by all information so maybe someone can help me out here as I am not a car technician but am eager to learn as much as possible.

The problem:
Although my engine starts like a charm in cold and warm wheather and also runs properly, I always have a white/grey smoke during the first 1-2 minutes. Sometimes not that long, sometimes longer. When I have this smoke I hear that the engine is not running that stable and I hear some knocking and that it "puffs" more smoke during that knocking. Normally this should not have to be such a big annoyance,but having a camping car it is always somewhat embarrasing leaving other to people in your smoke when leaving. So maybe someone can help me to tackle this.

Some more info:
From this forum I have learned that it is difficult to pinpoint one single cause for this. I found that it might be the heatplugs, injectors or injection pump timing. Other people tell me it is definitely the injection pump timing which is probably not adjusted after a timing belt change. And they always say: don't try to correct this yourself but definitely go to a Bosch service garage for this.

My questions:
- The car actually starts whether warm or cold, without any problem. Wouldn't this rule out the heatplugs?
- The car runs properly, cold or warm. Wouldn't this rule out the injectors?
- This only occurs when the car is cold, there is no smoke when it is warm. Wouldn't this rule out the pump timing also?

Could someone please explain to me what might be most plausible and where to start?

[white exec]

Hi, and welcome.

From what you describe - smoke and noise/rough running for the first 1-2 mins - it sounds as if the glow-plugs might be providing pre-heat ok, but not offering "post-heating".

The duration of post-heat can vary from nil to several minutes (with a very cold engine). There is a temperature sensor in the coolant circuit, and this is what is read. The fault could be either that sensor, or the glow-plug relay (which incorporates the timing circuit).

Possible that just one (or two) glow-plugs have stopped working, but if your cold starts are fairly instant, and not lumpy, or with engine vibration, then all four are probably working ok . . . for pre-heat, anyway.

[Paul-R]

How many miles/kilometres has the van done? Have the glowplugs ever been changed to your knowledge?

[Simple76]

Possibly worthwhile having injectors tested .

[MikeT]

Glowplugs often fail long before injectors do and cost so little, I would have those changed first.

[Simple76]

Possible but normally be difficult to start and would run lumpy. Which is why I’d think to check injectors. But would test glow plugs first.

[moizeau]

Wax stat or wax stat cable, you can over come this by pressing the accelerator slightly to lift the revs to 1000. I bet that the tick over speed on a cold start is around 800, it should be a little higher. My BX does this, I just the raise the revs a little.

[EDC5]

Wax stat or wax stat cable, you can over come this by pressing the accelerator slightly to lift the revs to 1000. I bet that the tick over speed on a cold start is around 800, it should be a little higher. My BX does this, I just the raise the revs a little.

I was just going to mention this. Something similar happened on an old 306 with the Bosch pump. The little cable was slack even during cold starts.

Hi, and welcome.

From what you describe - smoke and noise/rough running for the first 1-2 mins - it sounds as if the glow-plugs might be providing pre-heat ok, but not offering "post-heating".

The duration of post-heat can vary from nil to several minutes (with a very cold engine). There is a temperature sensor in the coolant circuit, and this is what is read. The fault could be either that sensor, or the glow-plug relay (which incorporates the timing circuit).

Possible that just one (or two) glow-plugs have stopped working, but if your cold starts are fairly instant, and not lumpy, or with engine vibration, then all four are probably working ok . . . for pre-heat, anyway.

Does the XUD9 have a post-heating function? I thought it was only used for emissions purposes on the newer HDi engines.

[moizeau]

Elis, there's a little contact on the back of the wax stat cable at the pump, I think? it provides post heat but it doesn't seem to do a lot. It's the stat.

[white exec]

" Does the XUD9 have a post-heating function? "
Yes, it does (even on BX) according to Haynes, duration according to engine temp.

[CPtje]

Thanks guys, for all the inspiring information.

The van should have done about 80.000 km now and I don't know if the glowplugs have ever been changed.

I was not aware that there was a post heating phase.

So, for now the plan is:
1. Check the wax stat cable for proper functioning.
2. Check with a multimeter if the glowplugs are operating with a postheating phase. If not, try to find the temperature sensor in the coolant circuit and check this.
3. If the above are functioning I probably need to check/exchange the glowplugs. Is there anything special about doing this that I should take care of? Is any special tools needed?

Carlo

[moizeau]

If it starts within a second from cold the plugs are fine. If you take the feed wire off the plugs you can test them individually for continuity between the the tip and the engine block. It won't tell you if they are fine 100% but it will tell you if they are knackered. I think the post heat bit may be the electrical contact at the end of the wax stat cable, pump end, if yours has one?

[Bick]

It will start fine on 3 plugs but will smoke - seen this many times - replacing the glow plugs with some decent ones Beru or Bosh usually sorts the problem.

[Gibbo2286]

Nobody suggest water droplets in the diesel?

[CPtje]

Update....

1. Checked the stat cable -> seems to work properly
2. Checked post heating phase -> Voltage on glowplugs for a couple of minutes after engine start. So seems to be OK.
However: after the voltage going low, there was still white/grey smoke, probably due to the fact that the engine temperature was not high enough yet during idle. Normally when I start driving (load) the smoke disappeares much faster than during standing still and idling (no load to engine). Probably normal but maybe not?
3. Took out (fiddled out (don't know if this is proper English)) the glow plugs. Appears that there are 3 older Beru (023 0 100 226 366) and one newer NGK (Y924J) mounted. All show a black greasy substance covering them, hope this is normal.

So, what would be best....just exchange all 4 of them with Bosch Duraterm (or the same Beru type, don't know if that is the original?) or... try to check them and exchange not proper functioning ones, whatever that may be.
What is the normal service interval for the glow-plugs?

Carlo