SnapDragon

06 Smart CDI Smoke while coasting

52 posts in this topic

I was driving around town today and noticed as I got off the gas pedal after climbing a hill, the car would throw quite a lot of black/grey smoke out the back. I was not able to recreate it consistently but it has happened more than once out of the blue. One time, I pulled over after the smoke started coming out the tail pipe from finishing an uphill climb. At idle there was no smoke but if I were to bring it up to 3k rpm and let the pedal go, the black smoke would spray out. After around 3 times of punching the gas, the smoke subsided like nothing had happened. Car still has all the power from before and no extra oil or fuel consumption has been noticed. EGR was cleaned around 400km ago. Could this be some sensor issue? 

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When I bought my used 2005 Cabriolet in 2007 I would park it on my driveway pointing uphill.

 

A few days later I noticed oil oozing out of the air intake on the left hand side. Checking the oil level revealed that it had been significantly overfilled. I removed at least 1 liter to go below the fill line on the dipstick.

 

My reason for telling the story is to ask if your car has been ovefilled and oil is veing vented into the intake from the PCV valve?

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I think that oil staining was from someone trying to fuel up through the air intake.  It's just not possible for oil fumes from the sump to get back to that point and ooze out of the LH air filter intake. 

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1 hour ago, SnapDragon said:

I was driving around town today and noticed as I got off the gas pedal after climbing a hill, the car would throw quite a lot of black/grey smoke out the back. I was not able to recreate it consistently but it has happened more than once out of the blue. One time, I pulled over after the smoke started coming out the tail pipe from finishing an uphill climb. At idle there was no smoke but if I were to bring it up to 3k rpm and let the pedal go, the black smoke would spray out. After around 3 times of punching the gas, the smoke subsided like nothing had happened. Car still has all the power from before and no extra oil or fuel consumption has been noticed. EGR was cleaned around 400km ago. Could this be some sensor issue? 

They do smoke a bit - our first on did a tad even when new, the day we bought it.  But it's a question of how much.  A black cloud would be weird and point to something other than the usual minor smoke.

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As for the how much smoke is coming out, I would say enough to be able to see through the rear glass while driving around. Cloud was translucent and for the couple of times where this smoke came on to blanket the cars behind me, no complaints from them. Ill try to get a video the next time it shows.

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Is your car remapped?

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Posted (edited) · Report post

8 hours ago, MikeT said:

I think that oil staining was from someone trying to fuel up through the air intake.  It's just not possible for oil fumes from the sump to get back to that point and ooze out of the LH air filter intake. 

 

I doubt it. It wasn't oil staining, it was oil oozing.The car was extremely overfilled with oil.

 

I don't know where the PCV valve output enters the air stream, but when parked on a hill nose up can't oil from the intercooler flow into the air intake?

 

According to Tolsen "air still containing some oil enters air inlet duct just before turbo"

 

Breather pipe repair

 

https://www.evilution.co.uk/Engine/top_breather_pipe_repair.htm

post-3908-0-98125600-1447002656.png

Edited by smartdriver
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Maybe pull an injector out to see what condition it is in, carbon wise...?  IF it is covered in carbon then this has been going on for a long time maybe and now it's just gotten so bad that it is stopping the injectors from being able to dispurse the fuel correctly and it's not being burnt as it should, so after a hardish effort period it results in this cloud you are seeing...?  Just a guess...?  Black smoke is un-burnt fuel imho...or far too rich which is basically the same.  Grey could be residue getting kicked out after the fact?  What does your intercooler look like? No oiling from the front bottom edge?  Rubbed through? I'll bet as it has been said above, too much oil and it has been pushed up through the EGR by the manifold pipe.  OR, maybe you wish to take the valve cover off and inspect it. The engine I rebuilt has about 1/8" of crud plastered inside it's cover and maybe yours is the same but worse. The top of the inside of the cover has a vented area that leads to the tube which goes to the EGR, maybe it's badly plugged or broken in some way?  Again just a guess..?  It was plugged up with the same sort of crud as the EGR gets plugged up with.  Gasoline is the best fluid to desolve this crud i have found. Unhealthy but it works!

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There is no PCV valve in crank case breather system on the 450 diesel Smart.

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I suspect EGR valve is the cause. Recommend you clean EGR valve plus fit blanking plate. 

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400 kms since last cleaning of EGR and installing backing plate simply stops crud and oil from entering EGR from valve cover system. IF valve cover baffled system is plugged it will continue to be an issue, not into the EGR but elsewhere within the engine. Better to clean valve cover IF plugged up with crud and then remove EGR from system all together. It's a simple process to remove cover and then split it in two but be careful as the inner section is glued down well but will come loose with persuation. Then you will see how badly carboned up it may be...?  It's just a time consuming job and a dirty one as that black crud gets everywhere once you get your hands in it.  Enjoy.
The real issue is why is it so crudded up in the first place...? Just poor fuel or bad fuel spray possibly from injectors to get it burnt completely..? 
To each their own, but any cleaning is better than no cleaning of mechanical parts especially when you have an unknown issue to figure out.  imho.,

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Nope....but that doesn't solve the issue just puts a band-aid over it.  
The question is why is it smoking in the first place...?   New clean engines do not smoke like this...?   Something in the system isn't operating as it should be, solve that and that'll solve the smoking issue also. It also will make the engine run more efficiently I bet...?  Maybe , maybe not...? 

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Fitting or confirming an EGR blanking plate is correctly fitted will at least rule out EGR as being the culprit. 

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Nope, it eliminates the valve cover crud as the culprit as it's now blocked out of the system. I'm not sure but doesn't the engine require a way for the valve cover to breathe in the first place...? Not sure again but isn't the route of the EGR the only way that the valve cover can vent..? IF the rings are allowing gasses past them where does that excess pressure go if you block off the EGR...?  Yes I too have blocked it off, but mine didn't smoke, so I don't have any personal experience with it. Just spit balling  for a possible solution...
Perhaps the OP needs to undo valve cover oil fill cap and allow it to simply sit on the top and see if it gets blown off or bubbles around or perqulates while the engine is idling and also as the RPMs are increased and then dropped...?  IF it does bounce around then maybe it's a badly worn engine...?  Ring wise that is. Possibly warped cylinders like mine was, but again didn't smoke like the OP.

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For MikeT, my smart is not remapped. Bone stock and just had a oil gear pump repair and new chinese CHRA (previous one blew up after low oil pressure).

 

I will take out the EGR and clean it again. For the blocking plate, I have read from somewhere that I should block on the exhaust manifold side to limit turbo lag? I will also check injectors and that valve cover thingy for blockages. 

 

As for the valve cover venting questions posted by Willys, doesn't the valve cover vent hose lead into the TIK pipe where then the fumes are then forced through intercooler to EGR and finally into the intake manifold? There's a little hole that appears in the TIK pipe to the right of the flexible joint in MikeT's illustration that he posted and I believe that is where the valve cover gasses pass into the system. Blocking off the exhaust inlet to the EGR should not affect the the valve cover gasses as the gasses still pass through the EGR and into the intake regardless.

 

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What's a Chinese CHRA?

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How many km since the turbo change?  Maybe you still have excess oil in the intake from the turbo failure.

 

Nigel

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Posted (edited) · Report post

19 minutes ago, MikeT said:

What's a Chinese CHRA?

 

its the business part of a turbo

 

the center piece minus all the auxiliary parts like manifolds 

 

center housing rotating assembly

 

Edited by LooseLugNuts
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7 hours ago, tolsen said:

There is no PCV valve in crank case breather system on the 450 diesel Smart.

In a previous thread you stated

 

"Oil on mine is separated out and ducted back to sump whilst air still containing some oil enters air inlet duct just before turbo."

 

My question then is if the 450 breather enters the intake just before the turbo, how much oil would be deposited into the inlet pipe if the car were significantly overfilled?

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Some... but none if it would find the way to the air intake on the car's exterior.

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Posted (edited) · Report post

For Nigel, the turbo change was done around 400 km ago.

 

Sorry to smartdriver for answering your question in post #2 so late. Car has 3/4 oil on level ground from the dipstick cold.

 

Just checked the injectors by taking the tips off and checking for 5 streams coming out of the tips. All of the injectors passed this test. Here is a picture of the one that had the most carbon buildup.

 

https://drive.google.com/file/d/16byYOVtamEpKMZHwIZM0wLP0g1agH9w6/view?usp=sharing

 

Will take a look at the EGR next and pursue a blocking plate. Will the car throw a code if I block it off? I am taking the car tomorrow to Eddy at Flying Tiger to get a read on all the data coming from the car (boost pressures, fuel pressure, etc.) and do an electronic transmission adjustment (TCU likes to dump the clutch on hills). Maybe this data can help diagnosis and I will ask him on what he thinks about this issue too.

Edited by SnapDragon
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Posted (edited) · Report post

13 hours ago, MikeT said:

Some... but none if it would find the way to the air intake on the car's exterior.

Not even if parked nose up on a steep hill? This would mean that the crancase oil was pushed to the rear of the crankcase. I am not familiar with how the inlet hose is routed or what path oil from the intercooler would take when parked nose up on a hill.

 

When I bought the car used in 2007 everything seemed fine until about a week later when I noticed oil ooziing out of the air intake on the left side. At the time there were a number of threads on the forum about overfilling the crankcase and when I checked the oil level it was way above the dipstick line. Removing about 1 litre resolved the problem.

Edited by smartdriver

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4 hours ago, smartdriver said:

Not even if parked nose up on a steep hill? This would mean that the crancase oil was pushed to the rear of the crankcase. I am not familiar with how the inlet hose is routed or what path oil from the intercooler would take when parked nose up on a hill.

 

When I bought the car used in 2007 everything seemed fine until about a week later when I noticed oil ooziing out of the air intake on the left side. At the time there were a number of threads on the forum about overfilling the crankcase and when I checked the oil level it was way above the dipstick line. Removing about 1 litre resolved the problem.

EDiT: Just another thought.

 

After buying the car I noticed that the driver's door handle had a great deal of vertical scoring on it as though the car had slid along the road on its left side,

 

Where would the oil from the intercooler go if the car were tipped on its left hand side?

 

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Hmmmm....?    Which car is this on...?

 

Hmmm....It's got a long ride to get out the intercooler it'self then it might get to the air filter housing then out the breather pipe or hosing.....it also would need to be tipped up for a long time imho to do this distance.

I'd be taking a very close look at the inter-cooler for a rub through situation, common issue also. 

Seems like there is more going on than meets the eye here?   You could get vertical scraping marks if you allowed the door handle to rest against a brick wall while getting in and out of the vehicle...?  IMHO, there would be far more damage to the door if it had been rolled over and slid down the road than a few scratches on the door handle..lol.

As for the car resting on an up-hill incline, where would the oil go..? There is a return line running down from the turbo that could fill up a bit if the car was on a serious incline....but it is a return line from the turbo, gravity fed to the crank case.  Usually rusted badly.  I'll go and look at the car in the garage tomorrow and get a better look at the issue.  You could also look at the pictures of my rebuild in WIKI and see if any of them show what you need to see..?  Just a thought as they are all out of the car so to speak and as it went together.

 

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