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B21playa

Rough m5

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Hi all

 

connected my car to ista today to check fault codes and change ckm settings. At the same time I programmed pdc as it showed an update. Since then car is ok on idle but even slight throttle and I can feel vibrations through the car. No fault codes showing, any ideas?

 

thanks in advance

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Cam/crank sensor causing a misfire at all?

 

Is it engine and not drivetrain related (giubo etc)?

 

Engine mounts?

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No codes to indicate that, just a sap too low

 

defo engine as it does it when revving car at standstill. The only think was the car was running on Idle for 30mins, not that should make a difference 

 

Got a set of spark plugs in order, will see if that helps

Edited by B21playa

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How do the fuel trims look in ISTA? Sitting at idle for 30 minutes may have caused a shift in additive trims if you have a small air leak. Does it smooth out under greater power or does it just bog down and die?

 

Might you have reset the adaptation values? That can take a while to 'bed in' and re-do corrections.

 

How do the rough running graphs look? Any cylinder imbalance? You might have heat soaked something like a coil long enough for it to play up.

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Hi

 

I will have to get it connected again to do this. It was definitely smoother at the top end of the rev range. Started the car later in the evening and seemed much better.

 

How do I get to the rough running graphs and cylinder imbalance?

 

Since getting the car I've left it has some hesitation which a mate of mine thought it could be due to air leak, guessing this would be from throttle body  connections?

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8 minutes ago, B21playa said:

Hi

 

I will have to get it connected again to do this. It was definitely smoother at the top end of the rev range. Started the car later in the evening and seemed much better.

 

How do I get to the rough running graphs and cylinder imbalance?

 

Since getting the car I've left it has some hesitation which a mate of mine thought it could be due to air leak, guessing this would be from throttle body  connections?

 

Aye, the rubber intake boots can split IIRC, worth having a poke around :) 

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I'm afraid I'm not familiar with ISTA but I'm sure it has the functionality in there somewhere!

 

Most popular air leaks are valve cover gaskets and bolt seals plus the small plastic elbow under the plenum (which cracks). Both are quite a bit of time to do as the plenum is held on with dozens of fastenings. Due to the expense and time to do the job I wouldn't chase those leaks until you know the adaptations are pointing that way.

 

Hesitation could also be due to tired old MAF's or the vanos solenoids needing a clean out. Note that when cold these cars have a really jumpy throttle, especially in sport mode.

 

New plugs might make a difference, especially if you have sooted or oiled them up when idling for that long.

 

If it is already getting better you might find the adaptations are moving back and the issue will go away after a little driving. They don't like to sit still.

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Took the car to work today and was fine until 5-minutes from work (25-min drive) when I could feel it misfiring slightly. Will get plugs done on weekend along with standard air filters to replace the K&N one's that came with the car and hopefully check rubber boots

Edited by B21playa

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There has been some internet debate that oiled air filters like those fitted to your car can damage MAF's by oil contamination so getting rid of those can't hurt. Just make sure the joints are tight where the plastic elbows fit to the plenum. The elbows / bellows are much more robust than the soft rubber ones on other E39's so don't tend to be a problem themselves but give them a once over to rule them out.

 

Take a look at your old plugs and remember which cylinder they came from. A lot can be read from those as long as it doesn't sit idling for long before taking them out. Oil down the plug bores on the outside of coils and plugs would be due to valve cover gasket leaks. If you do have to do those then also replace the bolt / nut seals and replace the white plastic elbow under the plenum while you are in there. If your temperature runs much below 78°C on the 'secret menu' on the cluster when driving on the motorway then your thermostat is likely gone and it is much easier to fix that with the plenum off too.

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Here's a picture of the plug from driver side front cylinder that I checked before having issue. This is when I decided to order new plugs. Only removing there was no oil residue down the bore, only leak I see is from the oil cap (genuine one ordered)

 

Temp runs at 78degC verified by hidden menu.

 

Car has 144k on it, and they are ngk plugs, but not bmw branded so they have been changed at some point.

 

0AD1674D-4C7B-42F8-96C7-1AB7D4E1CCAA.jpeg

Edited by B21playa

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Had a spare 5-minutes after work to change k&n air filters to stock, and on taking intake boot off the plenum, I swiped my finger inside to get an oily finger. I’m guessing this is not helping.

 

what causes oil in the plenum? 

Edited by B21playa

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At that age and mileage if it's more than a light film it may be the oil separator hoses are getting old and squishy, slightly hindering oil vapour leaving the plenum.  The lower hoses ideally need the thermostat housing out the way for access, I did all those on my M5 at around ~150k miles when I was doing the valve cover gaskets, thermostat and plenum off work.  I had oil in almost every spark plug well so were definitely due!

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The separators themselves are plastic vortex tube type things which should be fine with a good clean out, I re-used mine with no issues.  It's mainly the hoses get old and soft and cause issues, most often the lower ones as they're hard to get to.  Yes that tee is somewhere near the idle control valve so worth checking while it's off, also any other of the smaller vac hoses and check the intake gaskets don't have any damage etc.

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Ah right, didn’t realise they could be cleaned out. I had read somewhere they needed to be replaced. How many hoses are there and do you remember the cost of them?

Edited by B21playa

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I ordered the following in September last year when I did the work from Cotswold BMW on here, forum members get a discount also I believe.

 

Oil separator hoses top L + R - 11151406952/11151406953 - £60.84
Oil separator hoses lower L + R - 11151407344/11151406902 - £13.76

 

So in total 4 hoses, top ones are expensive for what they are but shouldn't need doing again for a long time.

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5 minutes ago, DatV8 said:

I ordered the following in September last year when I did the work from Cotswold BMW on here, forum members get a discount also I believe.

 

Oil separator hoses top L + R - 11151406952/11151406953 - £60.84
Oil separator hoses lower L + R - 11151407344/11151406902 - £13.76

 

So in total 4 hoses, top ones are expensive for what they are but shouldn't need doing again for a long time.

Many thanks, not too bad at £75ish

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+1 on oil separators and hoses though it is perfectly normal to have some oil residue in the plenum, it is just how they work. If there is enough oil to leak out into the air intake tubes then that can be a sign of vanos solenoid seals leaking or the outlet solenoid valves themselves leaking through and overwhelming the oil gallery they drain into during normal operation.

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Thanks

 

Do I need new seperators or can they be cleaned as mentioned above? Got a price of £76 for the hoses.

 

The lower hoses look like a bigger job and maybe one I will do when I can fit the car in my garage and not have to worry about weather (although I won’t have much space around it)

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I'd just clean your existing plastic separators unless they're obviously blocked or cracked/damaged.  I ran a load of brake and carb cleaner through them and let them dry out as I did other work, no ill effects afterwards.

 

Yes you need to remove the thermostat housing to access the lower hoses, to put this back you'll need the o-rings for the coolant tubes (plus spares).  That's a bit of a fiddly job, on reassembly you have to lube the rings with something like vaseline then be very careful and make sure you don't tear one as you put it back.  If you read up on it you'll see what I mean.  Ideally you'd pressure test the coolant system afterwards to make sure it doesn't leak otherwise like me in the past you're removing it again and putting a new ring(s) on.  I did all the work you mention in a single garage so space shouldn't be an issue.  It's all accessible from the front.

20170729_130812.jpg

20170729_130745.jpg

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As DatV8 said, I would be tempted to just clean them out, I'm sure 90% of the issue is the soft old hoses.

 

I'm not sure oil mist in the plenum is the cause of the misfire though. That old spark plug looks quite coated so I'm sure new ones will help to some degree. If you can find the cylinder imbalance / 'rough running' page in ISTA you might be able to pin it down to a dying coil or leaky injector if it becomes persistent enough.

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Thanks, ordered hoses from Cotswold, will be done when I can clear my garage out - hoping in the next week or so

Edited by B21playa

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Right, managed to check codes today and only got one for SAP.

 

Ran a vanos test and it says bank 1 is out of spec as per images. Could this be causing issue?

 

Should I remove solenoids and check them out on bank 1?

 

Thanks in advance

4071F194-ED38-41B7-9195-411ACEC83F9A.jpeg

CC69B079-9AEA-43E2-AC10-C34CE0A52D58.jpeg

37CFF305-B978-4A77-B0A9-F870B1D96E69.jpeg

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