Technical X2/50 black smoke, loss of torque at lower revs

[Peter James]

My 2008 X2/50 van – Citroen Relay 2.2 engine as fitted in the Ducato, but 120 bhp version.
I have had this van from new but now found the engine has suddenly lost most of its torque below about 2200 revs – just a lot of black smoke and little power. This is making hill starts impossible without burning the clutch. The only way I can get up a steep hill is to take a run at it – if the engine is doing over 2000 revs it will keep going. I used to make a living as a motor mechanic, but that was a long time ago and my knowledge is about 40 years out of date!!
No warning lights are coming on, air filter, oil and water are OK, have bled the diesel but makes no difference.
Any ideas please?

 

[moodrater]

My 2008 X2/50 van – Citroen Relay 2.2 engine as fitted in the Ducato, but 120 bhp version.
I have had this van from new but now found the engine has suddenly lost most of its torque below about 2200 revs – just a lot of black smoke and little power. This is making hill starts impossible without burning the clutch. The only way I can get up a steep hill is to take a run at it – if the engine is doing over 2000 revs it will keep going. I used to make a living as a motor mechanic, but that was a long time ago and my knowledge is about 40 years out of date!!
No warning lights are coming on, air filter, oil and water are OK, have bled the diesel but makes no difference.
Any ideas please?

Sounds like no boost, check the hoses for splits, check the egr circuit for leaks. Check the turbo actuator is moving when someone revs the thottle. Any light on?

 

[rayc]

Possibly MAF sensor.

http://tuning-diesels.com/75Zt/R75maf.htm

 

[Peter James]

Many Thanks for the replies. Am away from home so all I could do is try disconnecting the plug to the MAF sensor, then the EGR valve.Also tried disconnecting the battery for an hour in the hope of resetting the computer. Doesn't trigger any warning lights, or appear to make any difference though.

 

[Peter James]

colin - 2014-03-12 7:40 PM

Do you mean the MAP sensor? located just down stream of the air filter.

Sorry, perhaps it wasn't the 'MAF sensor' I disconnected. The confusing thing is the diagram I have doesn't call it a 'MAF' sensor.
Just downstream of the air filter is what they call a 'Hot film intake air flow sensor' I disconnected that and it made no difference whatsoever. So I reconnected it. But downstream of that is the Turbo, then the Intercooler. then just before it goes into the inlet manifold is what the diagram I have calls an 'Integrated air temperature and absolute pressure sensor' . I disconnected the electrical plug to that and it has made a remarkable improvement. The black smoke has gone, and the engine runs much smoother - no coughing or spluttering now, fuel consumption seems to have improved, and power is adequate

But it is still well down on its normal power, and the emission control system warning light now stays on - an MOT fail I think.
(which it didn't before when it was belching out clouds of black smoke .

).

 

[Peter James]

Just taken it out (held in by one torx screw) and it was solid with black crud so cleaned it up and have it soaking in petrol

 

[Peter James]

Well I put the Map sensor (pictured) back in after washing it in petrol, and it worked better, but sooted up again after about 40 miles, so I had to disconnect it again. At least with it disconnected the black smoke has almost gone and its driveable, but still well down on power and with the emissions warning light on - an MOT fail I think. I went into the Citroen dealer in Plymouth but they don't stock Map sensors, or anything much else for Citroen vans as nearly all their business is cars. So I can only drive it back home and try and sort it from there, where I can hopefully order parts on ebay if I can find out what to order.

 

[Oneill]

If it's putting out black soot ad clogging up the sensors,take off the EGR valve,and either use a proper cleaner or just blank it off.
It returns exhaust gas back into the intake,hence the parts getting clogged up.
I've done plenty of them to get vehicles through the mot for customers.

 

[moodrater]

Can't believe that didn't throw a mil in the first place thats bad ecu programming. You don't need to go to citroen to get one, try ford its the same engine as the transit. Other equivalent part numbers should be:
BOSCH 0 261 230 224
FORD 1503280 ,
FORD 6C119F479AB ,6C119-F479-AB ,
FORD M9101473 ,
BOSCH 0 261 230 225 ,0261230225 ,
EPS 1993205 ,1.993.205 ,1 993 205 ,
ERA 550413 ,
FACET 10.3205 ,
FAE 15098 ,
HELLA 6PP 009 400-611 ,6PP009400-611 ,
KW 493 205 ,493205 ,
MAGNETI MARELLI 215810004000 ,

 

[Peter James]

It returns exhaust gas back into the intake,hence the parts getting clogged up.

Thanks for the replies.
But the thing I can't understand is that when I disconnect the Map sensor there is a big improvement, with only normal smoke. (still a bit down on its normal power though, and with the emissions light on which I think is an MOT fail)
If the EGR valve is stuck letting too much exhaust gas into the inlet causing all the black smoke, why does the black smoke stop when I disconnect the Map sensor?

 

[moodrater]

Thanks for the replies.
But the thing I can't understand is that when I disconnect the Map sensor there is a big improvement, with only normal smoke. (still a bit down on its normal power though, and with the emissions light on which I think is an MOT fail)
If the EGR valve is stuck letting too much exhaust gas into the inlet causing all the black smoke, why does the black smoke stop when I disconnect the Map sensor?

He was saying the reason for the sensor getting gacked up with crud in the first place is the egr. The new sensor will end up the same way as will the entire intake.

 

[Oneill]

The MAF sensor in the intake controls the EGR.
If it's not working properly,it will have loads of black smoke/difficult to start.
The MAP controls the boost,and shuts down the car/van to save the engine from damage.
I'd get it scanned and check the live data for the EGR to make sure it's working ok.
I've got a snap on ethos tool,does the job.

 

[Peter James]

He was saying the reason for the sensor getting gacked up with crud in the first place is the egr. The new sensor will end up the same way as will the entire intake.

But why does it only produce black smoke when I connect the MAP sensor?
If the EGR was faulty, wouldn't it produce the smoke whether the MAP sensor was connected or not?

 

[Oneill]

The map sensor helps with fuelling and boost pressures,if it's faulty,you will have problems with power below 2000 rpm.
The ecu will try to compensate but will have the wrong settings.
You really need to plug her in and find the codes.
Don't just wipe them,take a photo,then do it.
Start up and run the van,the new codes will show up then.

 

[Peter James]

Thanks for the replies. Now home again and waiting for a new MAP sensor ordered on ebay as nowhere I tried kept them in stock.

 

[moodrater]

But why does it only produce black smoke when I connect the MAP sensor?
If the EGR was faulty, wouldn't it produce the smoke whether the MAP sensor was connected or not?

Because the map sensor is telling it that there is higher pressure than there is and/or higher temperature so the ecu is giving it more fuel than it can burn.

The egr doesn't have to be faulty to fill the intake with ****e, it passes the exhaust into the intake that by definition is dirty.

 

[Peter James]

Because the map sensor is telling it that there is higher pressure than there is and/or higher temperature so the ecu is giving it more fuel than it can burn.

The egr doesn't have to be faulty to fill the intake with ****e, it passes the exhaust into the intake that by definition is dirty.

But by that definition its the MAP sensor that is faulty. So why would the new MAP sensor end up clogged like the old one?
I do appreciate help - especially when its free and I am not ungrateful. So I am sorry to say you appear not to read posts before replying. Like in my opening post I said 'No warning lights are coming on' Then in the following post you ask 'Any light on'?

 

[moodrater]

So why would the new MAP sensor end up clogged like the old one?

Because the egr in order to reduce nox emissions is putting dirty exhaust gasses in your intake which is why disabling /blanking the egr is such a popular modification. Faulty/sticking egr accellerate the process but it will end up that way eventually even if the egr is operating correctly.

So I am sorry to say you appear not to read posts before replying

I read hundreds of posts on many forums every day and quickly parse the posts for relevant information so yes occasionally i miss some information especially when on the phone and you can only see part of a post at a time.

 

[Peter James]

Because the egr in order to reduce nox emissions is putting dirty exhaust gasses in your intake which is why disabling /blanking the egr is such a popular modification. Faulty/sticking egr accellerate the process but it will end up that way eventually even if the egr is operating correctly.



I read hundreds of posts on many forums every day and quickly parse the posts for relevant information so yes occasionally i miss some information especially when on the phone and you can only see part of a post at a time.

Thanks for the reply. I only use a large screen PC or Laptop and tend to forget some people are posting on these new fangled pocket things with tiny buttons and screens
The thing about this though is was alright to drive when the MAP sensor is disconnected. But as soon as you connect the MAP sensor you get coughing and spluttering accompanied by clouds of black smoke and severe loss of power.

 

[Oneill]

Get a multimeter and check the resistance.
You should be able to find out what the values should be online.
Personally,I'd blank off the EGR,it's a pain in the arse.