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Help !! Smokey on startup


cabby
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I'm at the end of my tether with with my X5 (2005 3.0D, 50,000 miles). The problem is a puff of smoke that lasts for a few seconds when starting from cold. The smoke hangs around in the air for a bit I guess due to being so heavy. It has been suggested this may be due to unburnt diesel though not 100% sure about this. Start the car any other time and there is no trace of smoke.

There is definitely more than there should be even for a diesel. The smell of the emissions on tick-over are also overly acrid.

In my 1 year of ownership the following have been carried out:

- 6 No. Bosch injectors replaced

- new cam sensor

- new breather unit

- 1 No. glow plug replaced

- service (think inspection I)

- ECU re-mapped (suggested as it has been jump started and this can screw things up).

- MAF unit.

The weird thing is that, after changing the injectors and then a few months later a glow plug the smoking had stopped only to gradually appear over time again. The car has undergone extensive diagnostic testing and is reporting no faults on the injectors + the glow plugs are all ok.

As you can guess, the above has cost a pretty penny and. Whilst I love the car, the smoke thing is driving me crazy + I find it downright embarrassing.

Most of the above have been undertaken by a respected diesel specialist. In addition to the above they have checked the turbo (this was OK) and run with the + cats off.

The MAF was changed yesterday and I was waiting with everything crossed when they called today - unfortunately the smoking is still there :ffs:.

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Quite often a puff of white smoke on a diesel cold start is due to the EGR valve, basically all the crap that is left in it when the engine is switched off gets burnt off producing a white cloud.

I had this on my Mondeo (not a BMW I know) and Ford's answer was that it was normal and perfectly acceptable.

I took off the EGR valve myself and cleaned all the gunk out of it and it cured the problem, I dont know if would have been a long term cure though as I sold the car shortly afterwards.

A lot of people blank off the EGR valve as it also makes the engine smoother, although I dont know if it's possible on BMW's.

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Had the same problem in my 330d and it was very annoying..

When I did the diagnostic check mine came back with 6 faulty glow plugs! Was told this was due to a dodgy control unit and hence caused an error logged on all 6..

Car was written off before I had a chance to change it..

People do say cleaning the EGR valve does help as stated by Tipex..

It might be worth posting on BMW Land - A Drivers Chat Talk Discussion Forum Board for UK BMW cars and owners 3 5 6 7 series Questions & Answers, they have a lot of knowledge of the 3.0 diesel..

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Quite often a puff of white smoke on a diesel cold start is due to the EGR valve, basically all the crap that is left in it when the engine is switched off gets burnt off producing a white cloud.

I had this on my Mondeo (not a BMW I know) and Ford's answer was that it was normal and perfectly acceptable.

I took off the EGR valve myself and cleaned all the gunk out of it and it cured the problem, I dont know if would have been a long term cure though as I sold the car shortly afterwards.

A lot of people blank off the EGR valve as it also makes the engine smoother, although I dont know if it's possible on BMW's.

Thanks for the suggestion tipex - will do a bit of research on the EGR valve.

It might be worth posting on BMW Land - A Drivers Chat Talk Discussion Forum Board for UK BMW cars and owners 3 5 6 7 series Questions & Answers, they have a lot of knowledge of the 3.0 diesel..

I'll give this forum a try.

Cheers fellas +++

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even if the glow plugs check out ok, there might be resistance in the wiring or relay that feeds them, put a meter on voltage scale, put the red lead on a glow plug + terminal and the - lead on the battery + terminal and turn the ignition switch to the on position, the voltage while the glow plugs are on should be below 0.5 v, what your doing is measuring the voltage drop under load, which gives a better indication of bad connectors/relays than measuring it without any load. its also a better way of checking enine earthing, meter + to the engine, meter - to chassis and crank the engine, you want as close to 0v as possible.

cleaning or blanking egr would defineatly be recommended also, plus, i dont know if yours is affected but many bmws are afflicted with poor turbo oil seals which weep when cold, theres been a few cases where they fail totally and the engine runs on sump oil until its completely screwed, unless you catch it quick enough and stall it. it should only take minutes to take the compressor hose off the turbo and look for oil staining, and if you see it get the seals done and take the intercooler off and thouroughly flush all the oil out. come to think of it you may as well just flush out the intercooler anyway, it costs nothing and cant hurt as long as you dry it fully before reconnecting it.

good luck.

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even if the glow plugs check out ok, there might be resistance in the wiring or relay that feeds them, put a meter on voltage scale, put the red lead on a glow plug + terminal and the - lead on the battery + terminal and turn the ignition switch to the on position, the voltage while the glow plugs are on should be below 0.5 v, what your doing is measuring the voltage drop under load, which gives a better indication of bad connectors/relays than measuring it without any load. its also a better way of checking enine earthing, meter + to the engine, meter - to chassis and crank the engine, you want as close to 0v as possible.

cleaning or blanking egr would defineatly be recommended also, plus, i dont know if yours is affected but many bmws are afflicted with poor turbo oil seals which weep when cold, theres been a few cases where they fail totally and the engine runs on sump oil until its completely screwed, unless you catch it quick enough and stall it. it should only take minutes to take the compressor hose off the turbo and look for oil staining, and if you see it get the seals done and take the intercooler off and thouroughly flush all the oil out. come to think of it you may as well just flush out the intercooler anyway, it costs nothing and cant hurt as long as you dry it fully before reconnecting it.

good luck.

So another few days at the garage and EGR valve checked + cleaned, voltage on glow plugs checked + OK. The (new / 6 month old) injectors have been removed and bench tested but nothing found.

I did mention the turbo seal but doesn't sound like anything untoward was found.

They are going to put it all back together tomorrow and test but doesn't sound promising :(:(:(:(:(.

Think I'll get on the phone to David Copperfield and see if he can do some disappearing for me :secret:

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Hi!

I hope they do sort it, here are my thoughts.

Probably before you had it the previous owner ragged it to death.

As mentioned a few times i had the X5 and the 530d (the later being the one i held on to for 4 yrs or so) and while the car its self was pretty faultless it did degrade. It become noiser, dirtier and more laggy. I blame most of this on the other half as it was fine until about 65k.

Steelwindette isnt the best for treating cars nicely and used it for the last 16k or so much more then i did. Being a yank she is from the "throw a brick at the pedal and hold on" school of motoring. It too left a smokey plume and often on harsh acceleration it would leave a low level dust cloud as the auto switched up.

I suspect highly that played a big part in the smoke issue. It dident stop working or break down or anything. You do see alot of RR and X5s etc being kicked quite hard, maybe yours is just worn out.

Geoff

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CCV breather getting dirty maybe? Air mass meter element not heating up as quickly as it used to? worn valve stem seals? (not likely though but clutching at straws now)

Edit: never mind, i looked back to first post, youve checked those already. sorry.

Edited by Autogas
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White smoke or blueish tint to the smoke? If it is the latter then most likely to be valve stem seals (from my non technical & limited experience background). Had this problem with my recently departed 320d. I dont think the unleaded that went through it at one point would have done them any good!!!!! (it was the wife not me!)

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Hoo-fuc£ing ray +++ - sorted.

Turns out the problem was in fact two seperate issues that clouded (boom-boom) the issue. No. 1 was falutly injectors (BMW and Watsons both confrimed this). When these were changed the smoking stopped. Then appeared progressively over the next few months.

After a few more minor interventions the MAF was changed (No. 2). The olde unit gave some odd readings but, when changed, didn't cure the smoking.

I discussed options with the garage and I asked that the injectors be removed + checked. They were bench-tested and ultrasonically cleaned. In the process they noticed a greater build up of deposits than would be expected given their age/mileage.

So, the replacement injectors were fine but, after several week/months of running with a faulty MAF were affected with the result being the smoking caused by the deposits. Only after the MAF was changed AND the injectors were cleaned were the benefits realised.

The garage has been exceptionally good throughout and extremely reasonable about this last bill. :beer:

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happy days! glad you got it sorted. fit a new air filter element and vacuum out the airbox while your at it if youve got MAFs failing early, its usually contamination that kills them. also be careful not to get any cleaning product containing silicon near the air intake.

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