# Smoking engine



## bigee

My camper is based on the 2007 [new shape] citroen relay with the 2.2 hdi diesel engine. For the last few months i've noticed a fair amount of black smoke coming from the exhaust when i put my foot down to accelerate at lowish revs. As the speed and revs pick up the smoke stops, and if i put my foot on the accelerator half way or slowly there is no smoke. The engine runs as smooth as ever at any revs, cruises at 70 no problem and doesn't seem to be down on performance. I've added diesel additive to clean out the engine which doesn't seem to have made any difference. It has been suggested that it could be a faulty or sticking egr valve. Anyone got any ideas? I have also been told that there are blanking plates being made by certain companies, so that the egr valve can be permanently removed if it ever goes faulty as the engine will run quite happily without an egr valve. Any one know anything about that, is it true? Many thanks.


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## bigcats30

Your normally means your not burning all the fuel......so could be quite a few different things that's wrong.

Incorrect timing
Dirty or worn injectors
Over-fuelling
Faulty turbocharger (ie not enough air to match the fuel)
Incorrect valve clearance
Incorrect air/fuel ratio
Low cylinder compression (eg sticking piston rings or worn components)
Dirty air cleaner
Restricted induction system (eg system too small or kinked inlet piping)
Other engine tune factors
Poor quality fuel
Excessive carbon build up in combustion and exhaust spaces
Cool operating temperatures


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## bigee

Thanks for that. Already checked piping from air filter and changed air filter. Unlikely that the engine has become worn all of a sudden, [seemed to happen all of a sudden] and ive thoroughly cleaned it out with the best additve on the market. Does seem to be over fuelling but dont know why. If the timing was out i would expect it to run rough, and these engines apparently have a chain , not a belt, so less likely to slip and put the timing out. May be an injector.


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## loddy

It's a build up of soot in the exhaust or the engine is overfuellng, not a big problem a lot of vehicles can be seen doing it especially after being driven steady, that's why on a MOT test they always advise you take it for a brisk drive and present it hot, have a look at the air filter or use a fuel conditioner/ cleaner such as Forte and that should be all you need to do

Loddy :wink:


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## Jagman

My (much older!) Ford 2.4TD had similar problem and the guy who services it said:

1. Manage the use of the engine better - make sure its given 'a blast' on every run to clear any soot (but don't blow the engine!) - wait until its warmed up - don't blast it from cold - when warm just stay in lower gear for longer rather than rushing into 5th asap to save money (!) and don't leave it idling for long when you stop.

2. Don't use 'supermarket diesel' as it often contains bio-diesel which he believes causes more sooty deposits ( this may be an 'old fashioned' view but he does seem to know his diesels!)

He advised Shell fuel - he uses it - and reckons he gets better mpg than with Tesco fuel and therefore off-sets the few pence price difference

3. Use a good additive regularly but not all the time

If it doesn't improve by next service he will investigate further, but at the moment he thinks it isn't serious, just 'engine management by owner'!!

Good luck!


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## Parrotspain

Speaking from experience, it could be the MAF (mass air flow) sensor that is usually fitted between the air filter and engine. If this is dirty, engine tuning is thrown out quite possibly resulting in high emissions, poor economy and smokiness.

I have had this happen on two vehicles:

Ford mk7 2.4 / Rollerteam
Nissan Terrano 

In the later case the problem (high emissions and smoke) was misdiagnosed as turbo failure and exhaust deposits by two professional mechanics

As a result, I cleaned the MAF of the Rollerteam with an amazing improvement in economy and less smoke

I did recently mention this in another topic , but that is buried in the Rollerteam specific forum. This sensor is rarely mentioned as a service item but if dirty or damaged will produce the sort of symptoms you describe. I cleaned mine with baby bud and switch cleaner, but go carefully even just to inspect it as they are a little delicate.

P


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## bigee

Thanks guys for your replies, it's pointed me in the right direction, i'll check out the MAF sensor and swap fuels and see how it goes.


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## loddy

If it's the MAF sensor you will get rough running and stalling,
44 years experience !!

Loddy :wink:


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## rayrecrok

Hi.

Do you have the engine idling for any length of time for any reason before you set off, it could be unburnt fuel in your cat and as soon as you set off and the cat gets up to temperature it burns off the fuel vapour, then back to cleaner emission.

ray.


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## john56

Over fuelling, for whatever reason, have seen brand new Citroen,s chuck out clouds of black smoke when booted,, BMW,s come to that.


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## john56

Over fuelling, for whatever reason, have seen brand new Citroen,s chuck out clouds of black smoke when booted,, BMW,s come to that.


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## Bimobil

My mechanic swears by Ebay link, Forte
It gets mine through the MOT with really low emissions.
Hope this helps...


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## Parrotspain

I have to beg to differ with Loddy - neither of my vehicles showed that kind of extreme behaviour, although if MAF is damaged, disconnected or removed, it would certainly be the case. I am only talking about mis-fuelling as a result of dirty sensor. May well not be applicable here, but surely worth a visual check.

P


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## duxdeluxe

Plus another one for a dose of forte. In your situation, I would try that first and then try using some of the premium (vpower or similar) fuel a few times and see how you get on before spending any real money on a deeper investigation


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## bigee

Hi guys. To answer a couple of questions, i usually do leave it to warm up before setting off but if it was unburnt fuel in the cat it would clear after a while. Did 430 miles this weekend but was still chucking smoke out on hard acceleration when i got home. I have tried the v-power diesel, made no difference. By the way i only noticed this problem a couple of days after the mot. Could something have been damaged or dislodged when it was rev'd for the emmissions test? And does anyone know where the MAF sensor and EGR valve is on this engine? Had a quick look but can't see em.


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## loddy

You wont find it if you don't know what it looks like

Loddy

http://www.ehow.com/clean-maf-sensor/

http://www.wisegeek.com/how-can-i-tell-if-my-egr-valve-needs-to-be-cleaned-or-replaced.htm


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## bigee

Thats true loddy. I know what the EGR valve looks like but still can't find it.


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## bigcats30

bigee said:


> Thats true loddy. I know what the EGR valve looks like but still can't find it.


use google images as that can get better results than normal google search


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## macbadger

*Classic sign of a remapped diesel engine management*

This sounds like a Classic sign of a remapped diesel engine management system.


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## Pudsey_Bear

I'm not sure if it helps anyone but having the same van and year I found this in my manual.

With the following instructions, handle with great care being the main one it seems.




Pour isopropyl alcohol in a clean spray bottle.


Spray the alcohol liberally over the MAF sensor. Be sure to cover the MAF sensor's wires, intake and all its crevasses to thoroughly clean the part. Do not touch or scrub the MAF sensor's wires because they are very delicate and could break. The alcohol will remove all the impurities on its own.


Place the wet MAF sensor on a clean shop rag or paper towel. Put it in a location where it won't get damaged or knocked over. Let the MAF sensor dry for at least an hour, until the part is completely dry. Putting it back before it's completely dry could give false readings and damage your engine.


Place the MAF sensor back in the vehicle.


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## aircool

Dodgey map or "tuning box" ?

Need codes and live data really if you've done the obvious checks first i.e. boost leaks from pipe work.


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