406 2.0 HDi (110) 51reg 67,000 mls

[MrBean]

Just failed MOT smoke test, despite renewing engine oil, filter and air filter.
Tester tried many times with the usual brutal static acceleration, but only brought the level down to 6.2
My driving style is for ecomomy, with the rev counter rarely going past 3000, so the tester suggested giving it a good thrashing and then trying the test again, but could this bring a level 6 to under the limit of 3.0? He also suggested trying an additive, but I have heard that this is not advised for HDi. There are no warning lights up, and engine runs fine except for a little noticeable black smoke if I put my foot down. Onboard computer registers mpg between 35 and 45.

[Welly]

I would run some Forte injector cleaner through it (most mechanics sell if your local shop doesn't) I've ran that stuff many times and even my local Pug dealer puts in a bottle EVERY service.

A good (sympathetic) thrash should help. Also if the car has been waiting around at the MOT place it will NEVER heat up again to 90 degs by just letting it idle. It would help a lot to run the test with a fully hot engine.

There could of course be a problem with the EGR valve, if you drive fairly steadily most of the time then these can choke up and seize causing more exhaust smoke. Replacement EGR's are about £90.00 I think but try the other measures first before you go replacing stuff as you might find it passes.

[mbell666]

Hi

Mine failed it mot on the some test. (99, ~145k at the time)

Garage took it for a good run to warm it (i don't think it was at 90) up and clear it out, it then passed. If it had failed it would have got forte stuff run through it.

If that doesn't fix it, it could be the egr (as Welton suggested) or an injector prob.

[MrBean]

Hi, Thanks for your advice.
My local supplier only had Normfest diesel additive, so added this to the quarter full tank. Just before taking it back for another smoke test, I took it for a 40 mile hard run. The result was to bring the over 6 level down to just over 4, so still a fail.
Is there any way of testing the EGR, or will I have to unbolt and remove it for inspection? Looking though the oil filler, the top of the engine looks very clean (does this help?) Are there other common faults with the HDi?
As it's already had new engine oil, filter and air filter, the tester has recommended taking it to a diesel specialist. I could also take it to a Peugeot dealer, but could end up with some enormous bill !

[mbell666]

I'd take it to the specialist, these hdi aren't very easy to diagnose with out the right equipment and knowledge!

could spend more messing round with it than it cost for a specialist to tell you what is wrong!

[MrBean]

Hi, thanks for reply, will go to specialist.
Something I've just remembered though. During the summer, there were odd occasions when the windows would be down (there're up mainly with aircon) when driving about town, and there would be a distinctive kind of whistling/air sound from the engine (not exhaust) when decelerating. That sound seems to have gone or almost gone. So something has changed. Any ideas?

[puggy]

The whistling noise is common on hdi's its the turbo mine whistles like a truck.

one thing you could check is the pipes going to and from the turbo cos when one of
mine split it smoked like a bitch also the intercooler

[DaiRees]

one thing you could check is the pipes going to and from the turbo cos when one of
mine split it smoked like a bitch

Oh yes, it did that!

....and here you are attempting to fix it!

[puggy]

Well thanks for that Dai i had almost forgot .... not

my day will come

[MrBean]

Hi,
Re. M.O.T. emmisions failure.
Thanks for all your replies.
Diesel specialist found no fault codes, so decided to blank off the EGR. The cost of £130.00 was a bit of a shock. This included diagnostics, making and fitting the blanking plate, and roadtesting.
Engine seems a little more responsive, and the M.O.T. smoke test today has come right down to an average of 2.0
Of course, I'm now thinking that for that money, could I have bought and fitted a new EGR myself! I think the specialist's view was that the problem would return next year, so blanking would be a permanent fix.
I will check fuel consumption and let you know if there's any difference, or any other changes.
Please let me know your thoughts and experiences on this.

[Welly]

It appears that when the EGR valve sticks it recirculates too much eggsauce gas which then restricts Oxygen in the cyliders which means the Diesel cannot combust fully and smoke is produced.

Blanking off the EGR will increase the NOx emissions into the atmosphere so you are naughty and will not be eligable for our 'green prize' this year.

Apparenly, according to DaiRees, when Puggy was bending down under that car above the Methane emissions from his bottom were so disgusting we have all been trying to cut down on our own 'footprints' to help make up for that sudden increase.

This winter is set to be a cold one and it has come to our attention that Puggy's rancid bottom-burps are solely responsible for this years climate shift.

Please take heed!

[Captain Jack]

And here is the smoke:

[puggy]

It appears that when the EGR valve sticks it recirculates too much eggsauce gas which then restricts Oxygen in the cyliders which means the Diesel cannot combust fully and smoke is produced.

Blanking off the EGR will increase the NOx emissions into the atmosphere so you are naughty and will not be eligable for our 'green prize' this year.

Apparenly, according to DaiRees, when Puggy was bending down under that car above the Methane emissions from his bottom were so disgusting we have all been trying to cut down on our own 'footprints' to help make up for that sudden increase.

This winter is set to be a cold one and it has come to our attention that Puggy's rancid bottom-burps are solely responsible for this years climate shift.

Please take heed!

just seen this and crying laughing

[puggy]

And here is the smoke:

cpt jack was handy with the old camera that day ,,,, very quick indeed and of course

just in the right place at the right time

Great day hope Dai organises one next year

[MrBean]

Hi,
Passed MOT ok with smoke test down from over 4.0 to 1.7 !

So blanking the EGR proves that the EGR was at fault?

As it's the diesel specialist that blanked the EGR, would you agree that this is an "acceptable cure", or do you think that I should renew the EGR?