Hey all, i have a Renault clio 1.5 dci 65bhp, which has done 120k miles.

 

When i first bought it, it started smoking quite badly (white smoke) and i managed to find out the turbo was done for really, so i replaced it and the smoking problem was resolved, for a while, but the mpg problem wasnt.

 

Now 2 months have passed and it seems it maybe arising again, during daylight there isnt much smoke but when i put my foot down for the first time after starting up the ammount of black smoke that comes out is unreal, after that it wont do it again, but during night time i leave a trail of smoke wherever i go when im on boost and the more load on the engine (i.e. hill) The more comes out. There seems now effect on the performance, but fuel economy is very poor!

 

No oil consumtion either from what i can tell.

 

Any ideas? thanks.

ok black smoke indicates to not burning fuel at the right mix ... so i would be checking your Boost pipes from the turbo>intercooler>manifold

its very common for diesels to pop/split the pipes due to the high psi Pressure they use

 

other than that it could be the turbo at fault

 

have you been checking your oil level ?

yeah, the black smoke its just after startup, then it wont do it again, i thought of it as like flushing the EGR. i have been checking the oil after replacing it last week.

Would it be worth attatching a scangauge to check what PSI it boosts at, to find whether it has a boost leak?

Im thinking EGR valve mate.

My Scenic i had with the 1.5 DCI was a bugger for it..

well u could have a blocked or part open EGR ... this would give u MPG problems and smoke a little but this all so normally comes with bad runnings and engine light

 

the OBD box isnt really going to tell u if u have a leak u need to check each pipe

EGR Valves are a common fault on these. Maybe sticking, try a clean first.

 

Alan........

Thats a good shout to be honest guys, ive given it a clean a few times, but how am i going to be able to test it without replacing it?

having a quick read, a lot of people are getting ECU warning lights on with the egr faults, im assuming this still could be related to me but the fault still within tolerances?

 

Thanks.

Just out of interest what do you call poor mpg? Whats your driving style like?

well i know a friend who can get around 800-900 miles to a tank with the same car, and im getting around 300 maybe a bit more considering it should get around 65mpg, and driving style is very relaxed with small acceleration.

Oh right fair enough, i had the same engine in a kangoo van and tbh with my driving it didnt do anymore than 39-40mpg...

 

Sounds like EGR valve though as said above.

http://www.renaultforums.co.uk/showthread.php?p=280628

Thanks quavey, had a good read, and it looks like a likely suspect, but later on in the thread the problem reappeared with a vengance, so im going to tread lightly.

 

More symptoms anyway, when casually driving all power seems to go at around 2k revs and i need to put my foot down a little harder to get through it, and also when on the motorway travelling around 70mph i can notice little 'puffs' of black smoke from the exhaust.

 

Thanks guys.

I'd suspect that you've got a leaking/ duff injector - had similar problems on my beemer... a Bosch diesel specialist could tell you pretty quickly if that is the problem, but not cheap to fix...

i also thought that rich, but i get no problems with starting even if the car has been sat for a week at a time, and i get no loss in power, just a flat spot in the same place but if i was to put foot to floor from 1.5k revs, i would get no flat spot. it just seems to be there on normal acceleration only.

i also thought that rich, but i get no problems with starting even if the car has been sat for a week at a time, and i get no loss in power, just a flat spot in the same place but if i was to put foot to floor from 1.5k revs, i would get no flat spot. it just seems to be there on normal acceleration only.

 

Fingers crossed then... Other possibilities: AFM failing, EGR gunked up, Crankcase breather blocked, boost leak...

 

If you can get it plugged in, especially with a specific reader, it should throw some fault codes to point you in the right direction - I know BMW has specific codes for the EGR valve operation (I do a lot of miles and it keeps coming back!), can't see other makes being different, just not necessarily part of OBDII.

haha yeah fingers crossed.

 

Ive had both Scan gauge and OBDII on and no fault codes from either, the scan gauge managed to removed the 'SERV' light (which funnily enough doesnt represent service so the manual says i should consult renault immediatly) but it came back after about 10 seconds....i dont know how to test this serv light without going to renault!!

 

Any ideas?

haha yeah fingers crossed.

 

Ive had both Scan gauge and OBDII on and no fault codes from either, the scan gauge managed to removed the 'SERV' light (which funnily enough doesnt represent service so the manual says i should consult renault immediatly) but it came back after about 10 seconds....i dont know how to test this serv light without going to renault!!

 

Any ideas?

 

It will be a manufacturer specific fault - I had to buy a Peake reader as a generic one wasn't getting any meaningful codes, as soon as I plugged it in I got a load of parameter faults for start up pressure etc; if you go on the Renault form, there'll prob be someone local who will plug it into the equivalent Renault code reader for you...

 

According to here: http://www.renaultforums.co.uk/showthread.php?t=14828 it's basically an engine management light:

 

Does the airbag light come on at the same time?

 

The SERV light is illuminated when the ECU senses a fault somewhere.It could be in the engine management system,airbag system or the ABS system.

 

If only the SERV light comes on,then it's the engine management system.

 

Failing finding someone on the forums, try a back street garage at lunchtime - they should be able to read the specific codes for beer money while the boss is grabbing lunch ;)

Cheers rich, gona get to work.

Well, this problem is still hovering around me.... since jan ive had it hooked up to a diagnostics test set and found no fault codes. also shown the EGR valve opening and closing signals were correct and my fuel pressure at the injectors were fine.

 

i changed the maf sensor as i the flat spot at around 2k revs was still hanging around and never settled anything.

i have also noticed it IS burning oil and is doing so a little faster now.

 

smoking is kind of intermittent, it builds up and starts to puff black smoke (also bogging down slightly), and i give it a bit of stick and a fair bit of black smoke comes out and its cleared for a while until it builds up again and starts to bog back down.

 

From time to time i also get white/grey smoke appear at random times usually after about 1h30 of my journey home. but that isnt all the time its only on 1/5 times i build the revs up through 3rd gear.

 

Any ideas? this is kinda annoying now :/

 

Many thanks, Hollings.

As above, clean the egr valve/throttle body etc. Also, whats the temp gauge reading? A duff thermostat would give bad mpg & black smoke, not to mention gack up the egr valve.

temp is good, egr been cleaned repeatedly, im burning oil though. any ideas?

I would check the basics first, diesel nowadays creates the dreaded growth, is there a filter/gauze in the fuel tank, could be simple fuel restriction. Black smoke could be caused by restrictions in air, as could white smoke when the fuel is injected but poor combustion potentially shows up as white smoke/fuel vapour, have you had the sir filter out of it? The service interval on my Scenic for the air filter is 48k miles, fuel at 36k miles according to the dealer, both far too long IMO. Have you changed the fuel filter? I would cut it open after changing it to see what debris is in it.

 

For me fule of thumb black smoke = this and white smoke = that is out the window as I have been caught out with things, for me 100% do the basics first, pump/sender out the tank, fule and air filter after that.

 

Modern vehicles (I work on commercials) are a fookin nightmare, good luck.

 

Cheers John

cheers mate that is somthing i havent changed (fuel filter) i suppose ill go and purchace one tmo ;)

 

thanks again, keep you updated.

 

 

but on the side note, im pretty sure oil on the compressor side of the turbo is not supposed to happen, maybe very small ammount but i get and ammount where when i tip the pipe upside down oil oozes out. (boost pipe from turbo to inlet manifold)

Does it have an intercooler on it, if there is oil in the compressor side it could be restricting air, have seen that causing all kind of smoke/performance issues.

 

Also i'd check in the tank in case there is a filter/gauze on the pump/sender unit.

 

Basics first, again have seen people jump and throw parts/money at faults without checking the basics first only to get their fingers burnt by something basic/simple being the fault.

 

Cheers John

Remove the intake side and check the turbo in case there is a bearing issue, look for signs of the compressor wheel hitting the casing, just in case the turbo is foobared:)