smoking under hard acceleration and misfire going uphill!

[hardflipman]

hi,
first of all apologies for not heeding the advice i was given here straight away when i first posted about this.



anyhoo, i seem to be having 2 issues with the car which is an e240 estate 98 or 99 not sure

1st is that under hard acceleration when the revs get above 3000 or so it spews out black smolke and will continue to do so for quite some time even if the car's switched off and started the next day for example. a loss of power also accompanies this. ihad been told that this was most likely the breather being blocked. so i got my mechanic to sort it. he said it was totally clogged up however after that being sorted it didn't resolve the problem. any ideas?

2nd is that when going uphill for extended period of time one of the cylinders stops firing. switching off and on again sorts it out. any idea what this could be? a friend told me one of his colleagues had the exact same issue in his diesel newer model e class which would make me think it is something common.

thanks in advance

 

[brandwooddixon]

Is your car diesel or petrol?

 

[hardflipman]

sorry, petrol 2.4 v6

also in my tootling around town i seem to manage a whopping 17mpg. seems pretty terrible to me...

 

[jibcl500]

Air flow meter ata a guess, spark plugs possibly need replacing also, all 12 of them. Could also be a coil pack is failing. Check air filter make sure that not clogged and when was the car given a proper service.

jib

 

[Aussie Nick]

It sounds like it hasn't had a proper service for some time. I was thinking that the rings may be shot too. But hard to say until all matters suggested by jib attended to.

 

[hardflipman]

the car was allegedly serviced before i got it in november. the service history is a little bit patchy - some quite long intervals between servicing. previous owner owns a garage so you'd think it would have been serviced properly. was absolutely fine for first couple of months but one day i put the foot down a wee bit going uphill and it started smoking.
i had initially thought it was rings as that made sense to me. however the fact it doesn't smoke all the time made me think it was something else...

yesterday afternoon it smoked when i started the engine. the car hadn't been started in a few days but most definitely wasn't smoking when i switched it off.

it's done 145000 miles if that makes any difference. i've only done a couple of thousand miles since i got it.

is there anyway to test the airflow meter (that's the MAF right?) rather than going and buying a new one?

don't know if i made it particularly clear but the 2 problems appear unrelated. i very rarely make the car smoke but doing 30 or 40 uphill for a wee while will make it misfire. although i have been forcing it into lower gears to go uphill as i thought it might be to do with low revs e.g doing 40 in 4th.

also the car definitely is using oil even though it doesn't smoke from day to day. i've currently got the warning saying oil level at minimum and it was full in feb.

 

[Aussie Nick]

I now think even more than I did before that either the stem seals and/or the rings are shot. Worn rings indicated by black smoke from exhaust especially when motor under load such as going up hill.Time for a compression test.

 

[Xtractorfan]

Blue smoke = worn rings and oil burning
Black smoke = burning excess fuel
Valve stem seals will create blue smoke after putting the accelerator down after allowing car to coast on the overrun..ie down a hill ..which will pull oil in thru the stem seals and then burn it when the accelerator is used again..

 

[hardflipman]

thanks for the replys

guess i'll be looking for somewhere that can do a compression test!