diesel emission test - help!

[tim]

The MOT is so close you can smell it...only one remaining problem for the BX19 TDX I've brought back from the grave, the emission tester won't let it through. The tester himself would happily pass it but computer say no. When this first cropped up I got a tin of the magic cleaning fluid, tipped it into the tank ( a jerrycan of fresh pump diesel in there on top of a minimal amount of what was there before the wagon was laid up five years ago) and took the beast out for a discreet blast. I took it up to about 4 in 4th and a bit in third, did about ten miles, and thought that should do it. Did it hell, computer still says no. Thoughts of injector grief, dead pumps etc....piss.
I asked around. The tester (an old spannerman) reckoned that if it was stuffed injectors you'd get a cloud of smoke on startup, which ain't the case. I didn't know we had a problem until it was plugged in. One of the garage guys took it up the road and said it felt a bit stuttery, but I can't say I felt that - except when nearly redlining it and was told that was to be expected. And then you could see the sudden cloud of smoke in the mirror... the general opinion was that injectors and pumps were pretty bombproof, but anyway there weren't items a home mechanic could do a lot with. Even checking the timing on the pump looks a handful. But the local Citroen garage told me that I'd done the 'cleanout' wrong - what they reckon is that I should have had it in 1st and 2nd and really flooring it, in short I was being a pussy. (Excuse, limited to a quiet country road as I don't fancy being nicked for five years back tax). It was also suggested I should put a fresh filter in and fill it full of neat cleaner, run it for a short burst and the leave it overnight for the cleaner to loosen up the shit.
So -who's got some thoughts as to where I go from here?

[richardd1652]

Im no diesel expert but did hear my mechanic mate telling me he,d cut a car back on the pump?Didnt have enough grunt to fight its way out of a wet paper bag but revved up nice and clean for Mr MOT man.Passed its test then he wound it back up again?
I may be talking bo**ocks but im sure thats what he said?
Richard.

[tim]

OK, willing to try if nothing else works - but what do I wind in or out, and by how much etc.... and where's the winder??

[Dollywobbler]

What state's your air filter in? I do know someone who used to remove the air filter in his truck for the test...

A weaker mixture certainly helps. Here's what happens when you up the fuelling... (and add a truck turbo!)

[kermit the frog]

Hi Tim
I would agree with Dollywobbler remove the air filter.
Also go for a longish run prior to going to the test so the engine is nice and warm.
Also Yes GIVE IT SOME BEANS in 1st and 2nd
I followed a 57 plate Audi today and when he put his foot down i could not see where the road went.
And that is a modern diesel.
good old bx diesels will be going long after they have died due to a failed high pressure pump or ECU.
We don't need common rail Bollocks to be just as eco friendly.

Regards Kermit.

[tim]

Problem is, like I said - the beast has been laid up in a wood for five years and therefore not taxed. If I get snapped by one of those portable cameras I won't even know it till I get the summons! If going up the Lamberhurst bypass in the inside lane in 2nd. laying down a smokescreen, isn't asking for a tug I don't know what is. Catch 22.

[citronut]

book it for a re/test then as long as your insured you can legaly drive it to and from the MOT station,

i use Bidge Garage Sedlescombe and when i take my customers diesel cars for a MOT from Hastings, i get just past the Westfield turn off then floor them in second two or three times each for a few seconds, till no more smoke shows, the other trick make sure you aim to get to the test staion just at the time its booked in for, and ask them if they can run the emmisions test before loging it on to VOSA's computer,

regards malcolm

[tim]

The last plug-in wasn 't computer linked, so no problem there, the garage is perfectly user friendly. I believe that you are meant to take a direct route from home to MOT shop so if I'm caught out in the open ten miles in the opposite direction, it could take a bit of explaining (yes, I've got several bullshit excuses ready as a backup...) and I still would like to be convinced that the only problem I've got is the lack of a decent cleanout. PS the air filter isn't brand new but clean enough - I could remove it but the emissions thing is off the scale, not just borderline. I suppose what I'm saying is that I can probably have as many free plugins as I want, but I'd like to present a working wagon next time. Also, it's getting a bit chilly out there and while I've been riding motorcycles all me life it would be nice to have some alternative wheels before the frost gets too deep. And strapping a benchgrinder to the pillion seat tomorrow am is going to take all the bungies I've got.

[citroen7]

why is a diesel of that age being tested for emmisions? surley it should be visual only

[scarecrow]

Mine always gets the probe up the rear end! I've never had a problem though.

[MULLEY]

I'd try a brand new air filter, i'd also change the fuel filter (not 100% sure if that affects the emissions?), i'd also put some biodiesel in the tank, say approx 30-50% of whatever amount you still have in it & then rev it away to the redline a few times & keep doing that until the smoking stops, then take it in for an emissions test. If it fails again, the guy should be able to advise which part of the actual emissions test it is failing on. Post that up here & hopefully the experts on here can diagnose what it may be.

Could possibly be knackered injector(s) which i believe can affect emissions. Another possibility is that the exhaust system is at fault, saw a recent article that some replacement non oem exhausts (inc cats) are faulty & are causing cars emissions to be way higher than they should be. Have you had any recent exhaust parts fitted?

[mat_fenwick]

It's a bit of a bodge to get it through, but what Richard is referring to is adjusting the max fuelling screw to limit the fuel (funny that!) going through. Depends what type of pump you have, Bosch is easier.
A bit of information on diesel pumps here.

Info on diesel smoke tests here.

[docchevron]

Ok, Bosch or Lucas pump?
Turbo or non turbo?

Some stuff that may help lower the emissions here:
Change the oil, and run a flushing agent through it before draining the old shit out.
Changing the exhaust can have dramatic effects on the emissions aswell.

Get the things good and hot, like, REALY hot, then you'll need to drive it FLAT OUT on the govenor in bottom gear for as long as you can.
Simply revving the guts off it with no load on the engine wont do anything other than strain things that shouldn't be strained.

As above, removing the air filter will help too.
Running a couple of bottles Forte Diesel Conditioner through the fuel system will help aswell, but it's hard to get unless you know a man in the trade willing to sell you some.

[tim]

All useful stuff, thanks guys. Tomorrow I'll check what type pump it is. The car is non-turbo. An oil change is a good move and I had it planned, however the tester was very specific that it was diesel emissions not oil smoke (I have the printout if that helps at all, all greek to me!). I'm not a fan of flushing oil as it can loosen up all sorts of crap better left undisturbed but if the concensus is that I should do it, then OK. But how would this affect the emissions in question? (I'll answer that myself after another test on Monday). In any event, I'll change it tomorrow. The garage gave me a tin of Quantum system cleaner which is in there now, plus another tin to fill up the filter. Anyone know the product? They use it themselves so it should be OK.

[Mothman]

For what its worth Tim,
my L200 failed its emissions on its first Mot. Garage dosed it with something which they said would sort it without fail and it did, all ok. That was 3 years ago and still passing without any further treatment so ime sure they have given you the right stuff. Then a good thrashing is in order.

Andy