BMW revving by itself

adocholiday

Hi all,

Noticed a strange problem with the car this evening. I picked up herself from work which is only a 5 mile round trip. The car started fine and was driving normally as far as I could tell. While waiting for her the car was running in neutral and I thought it was a little rough but nothing too heavy. When I got back I parked up and put it in neutral. The car started revving itself. It was idling around 850-900 which was a bit high. Then it revved up to about 1500 and dropped back. A few seconds later it climbed to about 2500 and would have kept going I think but I switched off the car in fear. I've been afraid to turn it back on again!

The only thing I've done with it recently is add 2 litres of oil on Sunday because it was low. After I'd added the oil it idled very rough but it evened out after a minute or so. It has been driving fine since except this evening. Anyone have any suggestions? Is my car possessed?!

Toyotafanboi

runaway diesel? at a guess. sounds like you could have been lucky.

what car, engine?

adocholiday

Hi sorry its a 2002 318ci e46 petrol

Toyotafanboi

2 litres is a huge top up. have you dipped the car since to make sure it's not over full?

adocholiday

Toyotafanboi wrote: »

2 litres is a huge top up. have you dipped the car since to make sure it's not over full?

The dip showed it being very low so that's why I put in 2. What would overfilling do? Cause something to stick? Full oil change is now number 1 priority so

ants09

adocholiday wrote: »

Hi all,

The only thing I've done with it recently is add 2 litres of oil on Sunday because it was low. After I'd added the oil it idled very rough but it evened out after a minute or so. It has been driving fine since except this evening. Anyone have any suggestions? Is my car possessed?!

Check your oil cap to make sure she on right and is tight, as if she's not sealed right the engine will be rough and she will rev by herself

YbFocus

It may seem obvious but did you dip it when the car was on level ground?

listermint

Check your intake hoses. I'm gonna say it is either split or loose. This can cause the maf to get funky readings and engine revs to prevent limp mode.

Also check the cam sensors on the front of the engine as you could have covered them in your oil making them funkyd up. They will need to be cleaned off if that's the case

adocholiday

Ok I've checked the oil. Definitely a good bit too much in there. I started it up let it get up to temp revved it, turned on and off air con, lights etc and it behaved normally. No hunting and all running smooth. Not burning oil either no blue smoke or anything. Maybe just a one off fit of madness?

Edit @listermint what intake hoses are we talking about? And where are the cam sensors? I'm going to give everything a once over anyway

YbFocus

Its a far worse thing to have too much oil than too little. Within reason of course, but a litre too much is catastrophic compared to a litre too little more than likely being ok.
Don't drive it without getting the excess out of it.

Oil can't be compressed and so every seal etc in the engine is under huge stress!

adocholiday

YbFocus wrote: »

Its a far worse thing to have too much oil than too little. Within reason of course, but a litre too much is catastrophic compared to a litre too little more than likely being ok.
Don't drive it without getting the excess out of it.

Oil can't be compressed and so every seal etc in the engine is under huge stress!

Crap ok there's a probably around a litre too much in there or a bit less. What's the quickest way to get the excess out until I can do a full oil change?

YbFocus

adocholiday wrote: »

Crap ok there's a probably around a litre too much in there or a bit less. What's the quickest way to get the excess out until I can do a full oil change?

Sump plug. Let some out. It will be messy.

Unless you have an oil extractor?

adocholiday

YbFocus wrote: »

Sump plug. Let some out. It will be messy.

Unless you have an oil extractor?

Nope and I'm in my apartments underground car park so messy is trouble. Any way to siphon it out no?

This might be a stupid question but is the engine under stress with too much oil when the car is off?

lintdrummer

adocholiday wrote: »

Nope and I'm in my apartments underground car park so messy is trouble. Any way to siphon it out no?

This might be a stupid question but is the engine under stress with too much oil when the car is off?

You'd need a fluid pump with a hose narrow enough to get down the dip stick pipe. The extractor mentioned above is designed for exactly that purpose.

You won't be doing any further damage unless you start the engine.

adocholiday

lintdrummer wrote: »

You'd need a fluid pump with a hose narrow enough to get down the dip stick pipe. The extractor mentioned above is designed for exactly that purpose.

You won't be doing any further damage unless you start the engine.

Thanks for that. Ok so the messy path it is. I'll see if I can get a paddling pool to put under the car so to not spill any in the car park!

Avns1s

adocholiday wrote: »

Thanks for that. Ok so the messy path it is. I'll see if I can get a paddling pool to put under the car so to not spill any in the car park!

It shouldn't be that messy. Get a load of old newspaper. You're as well to do a full oil change as it will be difficult to get the bung on when the overfilled 1 liter is out. Refill to the correct level with new oil to the correct spec.

Tip - cut the side off a 5 litre oil can to collect the old oil.

No Pants

Weren't Lidl or Aldi doing oil extractors recently? Check if any of your friends bought one.

arleitiss

Could be MAF.
Had same **** happen to me a year ago.

Kenny Logins

Halfords do handy catch pans (4l container with a tray on one side) for about €6.50

listermint

Kenny Logins wrote: »

Halfords do handy catch pans (4l container with a tray on one side) for about €6.50

Don't forget the newspaper. Oil never goes in these things without a fight..

burke027

listermint wrote: »

Don't forget the newspaper. Oil never goes in these things without a fight..

Never mind any of that
I work on names and I'd imagine your problem is a blocked breather valve r crack in one of the pipes I guarantee u it is. As said tho get the oil level to what it should be to much isn't good either

No Pants

listermint wrote: »

Don't forget the newspaper. Oil never goes in these things without a fight..

And have a bottle of Fairy Liquid or something similar handy to take care of any that does make it as far as the ground.

adocholiday

Thanks everyone for the great help and suggestions. I'm going to try to just drain a bit out this evening and then I'll get it in a right place to do an oil change. I'll have to get an oil change kit but need the car so immediate quick fix required until Saturday. I'll take all of your advice into consideration and after that's sorted I'll start looking at the various hoses and sensors. Thanks again

obezyana

I don't get people who think changing or draining oil is a messy job. It's very easy, get a pan undo the plug and catch the oil...... Job done.

Avns1s

It may be messy enough when the OP is trying to put that sump plug back after just letting out a litre!

But for an normal oil change, I agree with you. In fact, I generally spill far more, when I'm tipping it from the flat can into the large drum that I bring to the recycling centre when its full, than ever gets spilled from the draining of the oil from the engine!

obezyana

What I find that works just fine when draining an overfill is to open the plug slowly as soon as the plug is almost open and there is a run of oil then don't open no more just let it run and it does the job with no mess involved.

Avns1s

obezyana wrote: »

What I find that works just fine when draining an overfill is to open the plug slowly as soon as the plug is almost open and there is a run of oil then don't open no more just let it run and it does the job with no mess involved.

You have more patience than I do - a lot more!!:)

Gazzmonkey

obezyana wrote: »

What I find that works just fine when draining an overfill is to open the plug slowly as soon as the plug is almost open and there is a run of oil then don't open no more just let it run and it does the job with no mess involved.

Had to do this a few days ago, just turned the bolt enough for the oil to start trickling with a measuring jug sitting under it, when it reached one litre tighten the bolt and check oil level.

Alanstrainor

OP where are you based, I have an oil extractor and am based in South Dublin. I could give you a hand if you're not too far away.

the.red.baron

YbFocus wrote: »

Sump plug. Let some out. It will be messy.

Unless you have an oil extractor?

do not do this, 100% do not do this

wonski

the.red.baron wrote: »

do not do this, 100% do not do this

Do not do what exactly?

Avns1s

the.red.baron wrote: »

do not do this, 100% do not do this

visual

I be of the mind to change the oil and filter as your more than halfway there draining out a litre.

But nothing wrong with opening the sump nut and draining out a litre then checking the level afterwards.

YbFocus

the.red.baron wrote: »

do not do this, 100% do not do this

At least you stayed around to explain why I'm so wrong

Sure just leave it in there to hell....

obezyana

YbFocus wrote: »

At least you stayed around to explain why I'm so wrong

Sure just leave it in there to hell....

I think it was a case of keyboard Tourette's.