Diesel 'smoke' from exhaust at high speed seen in headlights

Post by **Welly** » Thu Nov 02, 2006 12:07 pm

You know when the car behind you has it's headlights on - you can see if there's any smoke from your eggsauce quite easily by looking in your mirrors.

I know Diesels emit a dusty, sooty smoke which is more visible at night but I noticed at high speed 90 - 100 MPH there was a fair bit of continuos smoke, the engine was running at 3000+ RPM and very cold ambient temps (last night).

It's just that I don't get any smoke when accelerating hard at low speeds but I do get some at constant high speed (where I'd expect it least I suppose).

Can anyone else relate to this, I was trying hard I suppose (I had an Audi TDi on my tail, who just had to get past and I was waiting for a gap to return to).

mjb · Post by **mjb** » Thu Nov 02, 2006 10:13 pm

Ah but was it smoke or steam though... Probably the latter. A mixture of your engine running hotter from your "trying hard", low ambient temperature and the extra chilling effect of a however fast wind would almost certainly be inducing vapour

Captain Jack · Post by **Captain Jack** » Fri Nov 03, 2006 6:42 am

Yeah I get this smoke at high speeds and also when accelerating hard at low speeds. Don't think it's anything to worry about on a diesel. Mine passed the smoke test with flying colours 2 weeks ago.

Post by **Welly** » Fri Nov 03, 2006 9:41 am

Tried it again last night (in the interests of science) and smoke not so noticeable at speed (may have cleared it out before).

I did notice smoke on acceleration though

I may just be I'm looking for it now (and I've seen Golfs and Audi's do it) but maybe it it's EGR time? but don't know if I would get LOUDS of smoke with EGR failure?

mbell666 · Post by **mbell666** » Mon Nov 06, 2006 1:49 pm

Welton wrote:
I may just be I'm looking for it now (and I've seen Golfs and Audi's do it) but maybe it it's EGR time? but don't know if I would get LOUDS of smoke with EGR failure?

I get quite a bit of "smoke" out of mine when accelerating (just about visible in daylight!) i also think my egr valve has gone as the shaft that runs through the middle of it is completely caked up in sot and it doesn't look like its moved recently. My brother has "invested" in a fault code reader, so next time i am up at his i plan to plug it in to see what it says. Not looking forwards to it, probably hundreds of pounds to spend!

I am not sure even if the EGR is dead i will replace it. From my understanding, its function is to allow exhaust gases into the inlet to reduce emissions, when the engine is not heavy loaded, and it reduces performance!

Post by **Welly** » Mon Nov 06, 2006 2:11 pm

I don't really understand the EGR myself and can't grasp why it makes the engine smoke so much if it fails

I kind of tested mine by leaning over the engine (with it running) and looking with a small torch at the spindle rod of the actuator whilst reacing over to the throttle switch and revving the engine.

I could see the spindle moving up and down and when you rev it it seems to close then open up again when you let off.

The spindle area is sooty and a bit wiffy with exhaust smell when you rev it.

They are expensive from the dealer though, Turbolag has removed his, I might ask him about it.

xplosiv · Post by **xplosiv** » Mon Nov 06, 2006 5:15 pm

Hi,

AS you know I have replaced mine (the new EGR I got was a completely different design), try moving the EGR yourself, by sticking your fingers in underneath the top plate and move it up and down (push the spring up to the top and let go, so it pushes some of the crap out), I did this on mine and the black smoke cleared for a small amount of time (which indicated EGR).

I think they are £70 including VAT and a new bracket to go between the EGR and exhaust thing (cannot remember what they are called)

Note: - On my car this did not solve the entire black smoke problem, I sent the car to a specialist and they discovered: -

A) I had a split in the vacuum pump
B) The Vacuum pump was on the way out (£30)

Which meant the turbo would not come on completely, thus leaving un-burnt fuel (black smoke)

Andy

Another point you mentioned a while ago your turbo sounds loud, mine does to I found a possible cause, the metal thing (again cannot remember what they are called) sealing the exhaust to the car (is held on with a spring plate arrangement, and mine is leaking apparently there is a repair kit from Peugeot you can get to fix it, I have ordered one.

REPLACING THE EGR VALUE ONLY TOOK ME 2HRS

turbolag · Post by **turbolag** » Tue Nov 07, 2006 7:33 pm

Weltie, I get exactly the same phenomenon on my HDi, especially evident in the darker days where headlamps are on more often. Despite this, my HDi has just passed its annual health check with one of the lowest emissions results for a diesel that the tester had ever seen, so i wouldn't worry unduly.

Post by **Welly** » Wed Nov 08, 2006 8:36 am

Fanks Turbie, It seems I was worrying unduely, bloody dark nights, dark nights I tell ya.......

neildavies · Post by **neildavies** » Fri Nov 10, 2006 1:29 pm

Always noticed it when I had my 2.1TD, and was often commented by people in work who had followed me, but just got used to it in the end. It always passed the Mot with a blast beforehand.

I used to also use a load of Forte deisel cleaner now and again, made a noticeable difference.

The smoke screen is great for cyclists who stay side by side and refuse to let you pass. Use a low gear when eventually passing them.

It's all change now though with the Coupe HDi's particulate filter.

Post by **Welly** » Fri Nov 10, 2006 3:11 pm

Your 2.2 filter is mucho expensivo, if you look at it it's 'plumbed in' with 2 pipework connections for the 'super juice' to do it's magic from time to time when its injected.

Here's one

I wonder if the standard particle filters go bad over time?

I've been looking at Audi's and VW's and they all churn out there fair share of soot on hard accelleration.

Quinny · Post by **Quinny** » Mon Nov 13, 2006 9:43 pm

Do not worry.

I drive artics,and when you floor the peddle,smoke is also apparent in any headlights behind me,and that's even on new trucks.

Ken.

slick · Post by **slick** » Sat Nov 18, 2006 12:08 pm

I reckon Welton was stoned

Post by **Welly** » Thu Oct 18, 2007 1:15 pm

Thread resurrection time folks!!

Last night I was travelling late on the motorway and noticed a fair bit of smokey dust from the old eggsauce again under boost.

No probs with performance but seemed to be smoking more than other Diesels (as far as I could tell).

Do any other HDi'ers have the same or am I constructing more things to worry about (again).

*remembers haven't changed the air filter since February 2006

OK, so it could be a dirty filter but I would like to know if anyone else has noticed this recently on their car.

miniman · Post by **miniman** » Thu Oct 18, 2007 2:28 pm

Not noticed this before Welly. And I regularly cruise at the ton+.
An air filter replacement/blow out is on the cards for sure. Has it been chipped/mapped?