Technical 1.9 JTD smoke

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Technical 1.9 JTD smoke


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May 24, 2005

I have a Marea 1.9 JTD (year 2001) with 110.000km on the clock and it has black smoke coming from the exhaust.

It does not burn any oil, since i've driven it 8000km so far and did not notice any change in oil level since i've changed it.

Water levels OK, too.

Starts OK (no smoke) even when cold.

The thing is, when accelerating, and revs are above 2500, black smoke comes out from the exhaust. If revs are even higher, above 3000, the amount of smoke increases rapidly.

It also spits out a giant cloud of smoke when I accelerate a bit harder (pedal about halfway to the floor), does not matter where the revs are.
And if I push the pedal to the floor, well, you can imagine the amounts of smoke I get.. :(

Some say that it is normal for a diesel to smoke, but my friend has the same Marea 1.9 JTD, altough somewhat older (1999) and I was driving behind him all the time on the 900km distance and could not see any noticeable amount of smoke coming from his exhaust. Also, when climbing a hill i would stay way behind him (same load in both cars). The same on a flat road, but less noticeable.

Also, I've driven a 50HP car before Marea and I expected a significant increase in power from a 110HP car, but it did not happen.

So, there must be something wrong :(

No error lights on the dashboard.

I've browsed through other posts, and came accross similar problems, with solutions like EGR valve cleaning, or mass air flow sensor, lambda sensor and so on.

What is the difference between air flow sensor and lambda sensor (if any)?

Where is the EGR valve? How to clean it?

Where is the MAF sensor? I've heard that someone recommended that MAF sensor could be boiled in water. Is this true?

Thanks in advance...
common problem on smoke is unburnt fuel being ejected from exhaust manifold.simple solution is plenty of injector cleaner down the fuel tank.2-3 bootles perhaps.then an italian tune up.give it a 15-20 blast down the motorway.this should cure it.if not,your injectors need to come out for an ultrasonic clean.also check air filter and box for cleanliness.
Black smoke is caused by :-

over fuelling
advanced ignition
restricted air intake.

As already suggested, do the easy bit first and check/change the air cleaner.

Advanced ignition isn't likey unless some bodger has been playing about with your ECU program. If this was the case it would be a lot faster than your previous 50hp car.

You can rule out the EGR by basically disconnecting it (illegal). Stick a small ball bearing into the actuator pipe. The EGR is the funny looking cylinder bolted to the top of the exhaust manifold

Over fuelling is possible however using injector cleaner isn't really going to help you as they are electronically opened and closed. Your mileage shouldn't need new injectors.

The MAF if dirty will give poor performance. Disconnect it and give it a drive then to see if you have any better power. It's the plastic cylinder in the plumbing between the air cleaner and the turbo. Just take off the electrical connection. Apparantly you can boil these to clean them but it's not something I've done myself.
Thank you for your answers.

I don't think that air filter is causing it, since I've changed it about 6000km ago, and did not notice any improvement.

I'll try to rule out the EGR and MAF problem as you described it.

I am not sure about injector lifetime, since the fuel in my country would not satisfy any European standards (being dirty and not of the correct composition), so maybe they are overdue already.

Anyway, I'll try EGR and MAF today.
sorry RS,but dont agree.ive had numerous diesels chugging out black smoke including mareas and bravo/bravas.before spending good money on the pump for example,ive just poured cleaner down the tank.after a run,the cars passed an mot.only time one did not was due to the cambelt timing being out.
Sumplug, I would agree with you for the older Bravo's and Mareas however the JTD is a common rail engine. The pump is purely providing pressure to the rail. It does not have any control over timing or injection quantity. The common rail pump does not need to be timed. The injectors are electronically opened, there is no spring in there to adjust for pop off pressure. If you had any debris in the injector, it would continuously hose into the cylinder and very quickly destroy the engine.

Although spending a few quid on injector cleaner is cheaper than replacing a system component, it is unlikely to give improvements on this type of fuel system.

Fbarcode, if you are running sub standard fuel, there is a very high chance of premature wear in the injectors mainly because of the extreme pressure of the fuel. Unfortunately, the common rail pump will wear much faster too if your fuel lubricity is too low. The pump is electronically controlled to produce a specific pressure and will counter some wear but it can only work so far before the fuel pressure is reduced too far for efficient burning.
Well, I could not try anything since battery died, and as I got the new one and replaced it, it was too dark to poke around the engine :(.

If I understood you right, the MAF sensor is in the plastic cylinder just left of the air filter box? In JTD It is much closer (lower) to the headlight then displayed in the 2.0 scheme I've looked at:

And if I drive my marea with this sensor disconnected, what side effects could occur?

Please forgive me if I bother you too much, but I am a kind of unfamiliar with these engines, as my previous car was Yugo (hope you know what kind of a car this is), and I could dissasemble and assemble again almost anything on it, but with all these sensors and stuff, I think I should go rather slow...
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The MAF sensor is where you described, at the front of the engine bay near the headlight. Although I have never personally run an engine with the MAF disconnected, there are plenty of posts from people who have on this forum.

I would give it a quick run like this to see if you have more power and if you notice a difference look to get it cleaned or replaced. With the MAF disconnected you'll probably get a warning light on the dash.

When we got our 130JTD it was very underpowered so I asked the garage to replace the MAF under warranty - they did and the power difference was incredible - a totally different driving experience. It will have gained at least 30% more power with the new MAF.

A dirty MAF wouldn't normally give black smoke though as it is not seeing all the airflow through it. This means that the ECU is fuelling for a lower amount of air than is actually being sucked in. I think your problem is on the fuel side.

Just thinking about the EGR. I've told you how to disable it but if it's stuck open the ball bearing will do nothing. Get someone to rev the engine whilst you watch the EGR - you should see it move (the inner bit) between idle and 3000 rpm. If it's working, blocking the actuator pipe will reduce smoke at lower revs and is a good trick to get engines through the annual test.

ps - We used to have Yugo's (Zastavas I think) over here too. I think they stopped getting imported about 20 years ago!
Thanks RS Pilot. I've finally disconnected the MAF sensor today. It did not want to go "peacefully", i had to apply some force to pull the connector out (someone tempered with it before so it was kind of stuck), braking some of the plastic around it, but nevermind it still has something to hold on to. :)

The thing is, I noticed significant increase in power (especially up the hill), and the engine seems a bit louder (but then again, maybe I imagine things). It would pull up the hill even on 1500RMP, and between 2000 and 3000 RMP it is just great. Now, up the steep hill it accellerates like on the flat road before. In iddle, it revs up much faster too. So the loss of power is caused by MAF sensor malfunction.

So, I'll try to clean it tommorow, and see what happens. The thing is, there are so many advices on how to clean it:

1. Iso Propil Alcohol (whatever this is) someone recommended the sensor should be dipped into it, but I am not so sure that this is OK, since the sensor could contain some parts which could be damaged by it.
2. WD40 spraying onto the sensor wires, not so sure again, since it leaves a thin film.
3. Electronic contact cleaning spray (this sounds OK)
4. Video/Audio head cleaning spray (this should be OK also, but not so sure about it's cleaning capabilities.

Did anyone tried something above?

Also, the amount of smoke is reduced now, but not significantly so my problem is in fact a combination of problems, so I'll try the EGR valve when I'm done with the sensor, and then, if necessary, the injectors.

I am quite happy with the engine power now, but not so sure if I should drive the car with MAF sensor disconnected.

RS Pilot,
You mentioned that I should block the EGR valve and that it helps with the MOT test (less smoke), but we here do not have to test the emissions in order to past the MOT (thanks to the domestic car industry "Zastava" which engines could not past even EURO1 tests even if brand new :) ).
Anyway, are there any undesirable effects possible after blocking the EGR valve?

Again, many thanks to you all.
my 110 JTD is awaiting a new MAF, as when the ignition warning light comes on i cant rev above 3000 with a general loss of power (forget overtaking) . But i dont get any smoke out the back, so while it sounds though you may need a new MAF there may be another issue as well.

My MAF will be £102 +VAT + Fitting from fiat, but you could easily fit it your self, Fiat will be doing mine as it is covered by my warraty


Good to know the power issue has been pin pointed :) . I personally wouldn't run the car in this condition as your engine management does not know how much air is going into the engine. At least when it's dirty, the engine is somewhat de-rated so you're not really going to damage anything.

Regarding cleaning, as it's already broken I wouldn't be too worried, although starting off with boiling water may be the least harmfull option (just boil the wire, not the electrical bits!) This is not something I have done, but it is something I will try when our power drops off the 130JTD.

Blocking off the EGR will help your engine breath better. The EGR is something any engine designer would love to scrap but is required to meet the necessary emissions. If you don't legally require it I would definately disconnect it. Think of your EGR as having the end of your exhaust pipe plumbed into the air intake because that is exactly what it is doing.

I should post this update earlier, but better late then never.
So what happened with my Marea next:

I tried to unscrew the MAF sensor, but realized that the thing holding it were not the torex with a hole, but it was a something star-shaped with a hole. So, where in the world would I find a bit like that? And I postponed the issue for a while... But in the meantime, even when I connected the wires to the sensor, the car seems to run fine, so I paid less attention to the problem.

Went to a 300km trip and back, and noticed that there was no smoke at all coming from the exhaust :).

When I came back into town, I tried to notice the smoke in circumstances which I would notice it earlier (at night, when some other car is behind with lights on, and I am pushing the revs over 3000, loads of smoke would be visible in the mirror). To my surprise, there was no trace of smoke at all.
So I stopped, reved the engine, still nothing. Pushed the pedal all the way, nothing.

Well, I can only guess what happened. The only things which I did were:

1. Change the battery (did'nt leave the car without power for more than 5 minutres)
2. Connected and disconnected the MAF sensor couple of times.
3. Drive a bit hard on a motorway (well to 'drive hard' is a bit subjective, depends on your usual driving habbits, but to me it is something over 150km/h in the 5th gear, revs about 3800). I usually never go over 3000, except on a motorway, in 5th gear.)

Something caused the smoke to dissappear....
It sounds like the ECU has reset itself and has started learning from all the sensors again due to having the battery disconnected. I suspect that you may have had a bad connector on the MAF too which has worked hand in hand with the ECU reset.

With diesels you can reduce a lot of smoke just by driving them hard for a few miles to 'clean the system out'. Any diesel owner in the UK presenting their car for an MoT should give it the thrashing of it's life just before. It often makes the difference between a pass and a fail. And then there's the trick with the ballbearing ;)
Well, the smoke is back :(

I was driving on the motorway this morning, and as soon as I got of, noticed something is not right... Lost power significantly and noticed smoke in the back again. The thing is, now it smokes before turbo kicks in (from 1000 to 2000RPM).
Did you ever get around to cleaning the MAF up? The ECU probably thinks it's not getting any enough air in again (ECU's are like the velociraptors on Jurassic Park - they learn!! :D )

The smoke dissapearing and then returning is a puzzle though! Clean up the MAF, reset the ECU (disconnect the battery) and please post back.
Thank you for your reply.

I could not clean the MAF since it is connected with a screw which is very odd, and I could not find the appropriate bit. Maybe it could be 'transformed' into an ordinary flat screw by grinder, but for now, I'll just let it be. I have disconnected it again, and the 'new' problem still remains:
When accelerating, from iddle revs to 2000, it just don't have any power (and smokes like hell), even if I press the pedal to the floor, and suddenly at 2000 RPM, it picks up and accelerates much better (but not as good as before).
It does not happen all the time and I think it is more often when engine is cold, but it happens also when warm.

Now, I read something about EGR valve causing this, but could not find the damn thing. Does anybody have a photo of it? I could take a picture of my engine and post it, so maybe someone could pin-point it?

I am realy puzzled now, since now the engine behaves completely oposite of the problem which occured earlier, and had it 'good' moment in between, which lasted about 5 days..... :(
remove the MAF from the air intake pipes via the jubilee type clips and 2 bolts. Then i use a small monkey rench to grip the sides of the screws and undo, they were only driven into the plastic case. After pull out centre as only held in by a rubber seal.

Clean with electrical cleaner, got mine from work 99.97% isoparppppyal (whatever its called :) )

Fitting was just a reverse of the above, the 2 screws arnt hard to get out, but be prepared to break the MAF doing so, I told mine was broken by Fiat so thought had nothing to lose

Thank you for your reply.

I am not so sure now that MAF sensor is causing the 'new' problem, as it appears that it appears random, for eg. when I drive to work, the problem is here, and when i drive back home, it's gone. I just don't know what to do now.... :(

I had a chance to see a (malfunctioned) MAF sensor from an Alpha JTD, just touched the sensor (metal strip in the middle) and it broke as it was made of paper, and that realy discouraged me from taking my sensor apart.
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