blue smoke at 30mph

hi can anyone explain what could be at fault, just been on motorway and car runs great no smoke at all had full service. got synergy2 fitted. but as soon as i get into a 30 zone hardly touching the peddle i start to get a lot of blue smoke from the exhaust. it is going in to garage next week but i would like some suggestions from you experts that i could pass on to the garage just in case he cannot come up with anything cheers

could be piston wear I do not believe in any of these gissmoes

Blue smoke usually indicates burnt oil, is the oil level dropping ? I would try disconnecting the Synergy first just in case this is causing the problem. As you only get the smoke at low speeds I wouldn't have thought it was burnt oil, more likely to be unburned fuel caused by a passing injector (do you get a miss-fire at low revs ?)

Hi tezzer,

I agree - blue smoke is usually oil.

What did you do regards the pcv?

Did you fit the BMW cyclone part, a new LR filter part, or just clean and replace the old one?

oil level is ok. I fitted a standard LD filter I spoke to a mechanic who works on heavy plant and seems to think it could be over fueling even though its blue smoke. can the synergy be turned off with the pierburgh maf fitted?. thanks for your replies

you can turn the power off and leave the MAF on

take the synergy off and see how it is, everyone assumes blue smoke is oil but it is also a sign of overfuelling on a diesel and as the basics of the synergy are that it overfuels its where i'd be starting.....

I have turned the synergy off and left the maf on but results are still the same. Is turning the synergy off the the same as disconnecting it as i don't want to take it off, if just flicking a switch has the the same effect. car is going into garage tomorrow so i will post what happens.:scratching_chin:

tezzer said:

I have turned the synergy off and left the maf on but results are still the same. Is turning the synergy off the the same as disconnecting it as i don't want to take it off, if just flicking a switch has the the same effect. car is going into garage tomorrow so i will post what happens.:scratching_chin:

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You're right - switching it off is all you need to do - no need to disconnect.

thanks for that
Singvogel

update I have just got car back from garage and the mechanic seems to think it could be the synergy2 whats causing the blue smoke. he has told me to first re-fit the egr and if this makes no difference to take the synergy off altogether. if i do this will i have to fit the old bosch maf back in again or will it be ok with the pierburgh left on. he has also found the rocker cover is leaking, also 0ne of the power steering hoses is completely flat not that these have anything do with the blue smoke issue

Can't you disconnect the synergy from the fuel rail sensor connecting the cars loom back to the sensor and leave the maf still connected to the synergy?....if not then yes you will have to put your old maf back on.

Hi
mjrimmer I think I know what your saying but i thought if do what he has said then he can,t say that i have not done what he suggested

tezzer said:

update I have just got car back from garage and the mechanic seems to think it could be the synergy2 whats causing the blue smoke. he has told me to first re-fit the egr and if this makes no difference to take the synergy off altogether. if i do this will i have to fit the old bosch maf back in again or will it be ok with the pierburgh left on. he has also found the rocker cover is leaking, also 0ne of the power steering hoses is completely flat not that these have anything do with the blue smoke issue

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Well I think your mechanic hasn't got a clue.

He has seen something that it didn't leave the factory with so he says "Take it off!"

I think if you remove the Synergy box you will not be able to keep the Pierburg MAF as it needs the Synergy to read it properly, so replace the original Bosch.

I can't see how refitting the EGR can do any good either.

If he started the engine with the cover off oil will come from one of the threaded holes so I'm not sure about the rocker cover leak report.

I have had a 'flat' power steering hose from new - I queried it with the dealer who said that 'was not unusual' - I was prepared to argue about it, but that was over 95K miles and 7 years ago and my steering is still working fine.

By all means do as the mechanic says - but I would be seeking a second opinion, myself.

thanks
Singvogel at least when i have tried it it will be something eliminated but I have a gut feeling it will still be the same. thanks for the flat hose bit cos it sounded like it was going to be costly for part and labour. when I start to take things off tomorrow I will have a look for the oil leak and let you know how things went with the egr and synergy2

1st thing to do is make sure the pins on the fuel rail sensor plug and socket are clean, a bad connection here can cause a multitude of running problems

Could need a new injector nozzle or needle on one or more injectors maybe, they may just be dribbling a bit.

today I have taken the synergy2 and pierburgh maf off completely. refitted the bosch maf, took the egr bypass off and put the egr valve back on. I then took car for a run and guess what? NO BLUE SMOKE. so i refitted the egr bypass took the car for a run and hey presto BLUE SMOKE AGAIN. i then took the egr bypass off and refitted the egr valve. ditto NO BLUE SMOKE. going to see how it runs for a few days now with the egr valve back on I have no doubt you will have some technical theories why this is happening. also this must have happened to a lot of you if you drop something below the engine how the hell do you get it out. as i have dropped the torx bit down there for the maf? PS if anybody wants a contest i am now an expert in fitting a synergy2 egr bypass and pierburgh maf in 20minutes flat

Hmm, very odd. As for the torx, you'll probably have to take off the under tray, unless your lucky with a magnet on a stick

When i fitted my EGR bypass I found that the increased airflow also increased the exhaust smoke and also hesitation in acceleration, this cleared after a run of about 300 miles. Burning off of the oil build up in the manifold and pipework was my guess (I couldn't be bothered to clean the manifold or pipework after fitting the bypass) and the hesitation was due to oil contamination of the MAF. Car now runs, after about 2000 miles, as sweet as a nut.