Help! My 540 needs it, major idle & smoke probs and no idea!

[leicesterboy15]

Hi All

This is my first post so please be gentle. This is an excellent forum, I have already found so many answers saving me time and money, I've had other cars before and the forums are nowhere near as good as with BMWs!

My problem all started on the motorway, been on there for about 2 hours all fine, stopped for petrol (had run down quite a bit), got back on and all ok again. Then we hit traffic and came to a complete stop, as we're almost stopped the car starts jerking like the engine is hesitating, you can see the lights dimming intermittently and it sounds like it wants to die so I pulled over. I can see no oil / water leaks, temp is fine, there is a whirring noise (like something is loose) that sounds like its coming from the front left of the engine, possibly under the valve cover or more towards the middle. Then found that the car was idling rough but as soon as you rev it over about 800 rpm its fine again, not rough and the noise disappears.

So (stupidly maybe but my 2 year old was in the back and we were in the middle of knowhere) I coaxed it easily to where we were going and parked it up. Next day the car starts fine but there is a cloud of white smoke on start up (then goes away), it runs smoothly when cold - idle or otherwise, but then when it warms up it starts to hesitate again and goes to a rough idle -not hunting but like its not running on all 8. As soon as you accelerate its fine again.

I took all the engine covers off and all looks fine, there is also a noise coming from the funny shaped thing in the middle (guessing its the air intake?), my friend says it sounds like air but to me it sounds more like an electrical noise. I've now got an 'engine oil low' warning on the comp after driving locally.

Recently (last few weeks) I've had a new radiator, full service, valve cover gaskets replaced, replaced microfilter, flat (so recharged) battery. I have now noticed a small fuel leak by the tank (had this before on my 535i sport). Guessing the pipes are corroded, will replace on Wednesday.

Does anyone have any ideas what this problem (s) might be? Is it related to the fuel leak (ie pressure)?

The engine bay is so full and it all looks so complicated I haven't got a clue where to start, the m30 was much easier to work on!

The car is a UK spec 1996 e34 540iA Touring with 130k, I hope thats enough info. Sorry to go on but I'm really stumped with this one and everytime I look at that engine is see £££ signs starring back at me!!

[pingu]

Idle problems can often be the PCV plate (do a search - they get gunked up) or the inlet manifold gaskets (searching should find loads about these but restrict your search to 530 and 540 as I think it's only the V8s that have a problem with these gaskets).

If the fuel leak is small then I'd be surprised if you were losing enough fuel to drop the pressure.

These V8s do "smoke" loads of condensation until everything is warmed up - when I first got mine, I used to get kittens the whole time in winter until I learnt that the condensation was normal.

[Barney Paull-Edwards]

Hi All

This is my first post so please be gentle. This is an excellent forum, I have already found so many answers saving me time and money, I've had other cars before and the forums are nowhere near as good as with BMWs!

My problem all started on the motorway, been on there for about 2 hours all fine, stopped for petrol (had run down quite a bit), got back on and all ok again. Then we hit traffic and came to a complete stop, as we're almost stopped the car starts jerking like the engine is hesitating, you can see the lights dimming intermittently and it sounds like it wants to die so I pulled over. I can see no oil / water leaks, temp is fine, there is a whirring noise (like something is loose) that sounds like its coming from the front left of the engine, possibly under the valve cover or more towards the middle. Then found that the car was idling rough but as soon as you rev it over about 800 rpm its fine again, not rough and the noise disappears.

So (stupidly maybe but my 2 year old was in the back and we were in the middle of knowhere) I coaxed it easily to where we were going and parked it up. Next day the car starts fine but there is a cloud of white smoke on start up (then goes away), it runs smoothly when cold - idle or otherwise, but then when it warms up it starts to hesitate again and goes to a rough idle -not hunting but like its not running on all 8. As soon as you accelerate its fine again.

I took all the engine covers off and all looks fine, there is also a noise coming from the funny shaped thing in the middle (guessing its the air intake?), my friend says it sounds like air but to me it sounds more like an electrical noise. I've now got an 'engine oil low' warning on the comp after driving locally.

Recently (last few weeks) I've had a new radiator, full service, valve cover gaskets replaced, replaced microfilter, flat (so recharged) battery. I have now noticed a small fuel leak by the tank (had this before on my 535i sport). Guessing the pipes are corroded, will replace on Wednesday.

Does anyone have any ideas what this problem (s) might be? Is it related to the fuel leak (ie pressure)?

The engine bay is so full and it all looks so complicated I haven't got a clue where to start, the m30 was much easier to work on!

The car is a UK spec 1996 e34 540iA Touring with 130k, I hope thats enough info. Sorry to go on but I'm really stumped with this one and everytime I look at that engine is see £££ signs starring back at me!!

Fuel pressure? UK fuel(petroland diesel) tanks in garages not regularly filled gives my diesel and petrol cars the shits, same symptoms.change filter next to pump under rear as first step.If you are keeping the car the two gauges I suggest you fit are fuel pressure and Water pressure(you`ll need an adapted boost pressure gauge for that), they both give early warning of doom and trouble.

[Tiger]

Ditto... PCV and intake manifold gasket. While you are here, take out the water pump and replace the oring in that bypass line too at the rear of the engine.

[bbig119]

Does the engine throw any error codes? check with a stomp test. Symptoms sound like intake leak/pcv plate problems that so many m60 owners complain about on here(including me).

[leicesterboy15]

Thanks for all the responses. I read the posts on the PCV plate and intake leak but doesn't this normally show when the car is cold? Is the area under the top engine cover the air intake? This seems to be where the air / electric noise is coming from. I've checked all parts outside the engine cover (idle control, air pipes etc) and there are no leaks. No takers for a head gasket? Car has not overheated once (yet), I will take a look at the oil and water tonight if there is enough light when I get home!

Tiger...the water pump was replaced only about 4 months ago, could the garage have screwed something up then? They are the reason I needed a new radiator and fan and now why my washer jets are not working.

Pingu...the fuel leak is small, there is not enough leaking to cause it to run away even overnight, just a small damp patch! I also get loads of steam but I know this is just condensation, I have never had the white smoke on start up until this problem popped up which makes me think its related.

What is the PCV? I will look at this next I think, I will also get the mechanic (a different one to before!!) to change the fule filter while he is changing the fuel pipes, any idea how much labour is invloved in this job?

Is there any chance of flooding the engine / doing any other damage if I have to try the stomp test a few times? What position does the ignition have to be in (and I presume with the engine off)?

[leicesterboy15]

Well I had the mechanic look at it today and when he started he said it filled the street with smoke and there was oil coming out of the exhaust, he says the engine has had it and the only option is to scrap it as a new or recon engine would cost too much. I am having real trouble with this as the problem came on so suddenly, there were no issues at all before this. And it only seems to be rough when warm and only on idle. Could he be right? Could the service / new water pump / valve cover gaskets have caused this if they have been done incorrectly?

Is there anything else I could check before it goes to the scrapyard in the sky?

At the same time I have been shot down with chicken pox caught from my daughter so I can't stand in the cold for too long hence the slow updates!! I love February

[Ross]

Go to a different mechanic.
If the smoke and roughness clear up soon after starting then chances are good it's only the PCV issue allowing oil into the intake.

[leicesterboy15]

Thanks, I think I do need a second opinion. The smoke is on start up like there is oil sitting somewhere and once blown out, theres no smoke. The roughness is only on idle when warm, when it gets above about 1000rpm it seems fine.

[Tiger]

Does the smoke smell like oil? I am telling you... on our V8 this is classic symptoms of bad PCV... which is supposed to prevent this. Intake leak is very common too that will also amplify the smoke effects.

Ha! That mechanic.... what a fake... You need to do a leakdown test before telling you the condition of the engine.

Roughness at idle is supposed to be like occasional lumpiness... but if it is a like constant consistent vibrations then it would be either leaky intake manifolf gasket or bad nikasil engine (which is very rare nowdays).