E85 N46 2.0 Rough Idle .... a tale of woe

johnsi02

Member
 Glasgow
It's been a bit of a week with the Zed.
She's been on a mission to tip me over the edge into insanity.....
Yet, it all started so well.
A simple mission to refurbish the steering wheel. What could be more mundane?
After taking suitable precautions to avoid being murdered by the airbag, the wheel came off just fine. The plastic spokes were even kind enough to not crack or disintegrate. There followed much hard work with wet and dry sandpaper to remove the festering remains of that weird covering BMW sprayed on the spokes all those years ago. Then a couple of hours trying to get the black dye from the weird stuff off my hands.
A couple of coats of etch primer, a couple of matt enamel black and a few of lacquer turned the embarrassingly awful wheel into a thing of beauty. Well, I thought so anyway. It looked great when refitted. Pretty chuffed at this point.
During this course of this process a parcel had arrived containing a couple of replacement Vanos solenoid valves. Preventative maintenance, you see. It makes sense apparently. Although I'm now wondering about that.
Fitting the valves is easy as many will know. Low maintenance. Requiring little skill and, I would suggest, with minimal disaster potential. They popped in just fine.
Time to give them a try, I thought. Turned the key. Nothing. Zilch. There's more life on Mars than in the engine.
Doh! The battery is still disconnected to avoid becoming the victim of 'homicide by airbag'.
10mm socket pops on the two terminals.
Nervously and from outside the car, I turned the ignition key. The airbag didn't try to murder me by decapitation but the engine nearly gave me a heart attack. To describe the sound coming from under the bonnet as 'bogging' does a disservice to bogs across the world. The idle was all over the place. Various pops and groans emanated from the pit of despair that used to be a sweet engine.
Oh my God, I thought. I've broken the Zed. Life will no longer be worth living. The shame. The heartache. The feeling of having hurt the one you love.
And then some common sense kicked in.
It's just an engine. There must be some simple reason for this. There followed a close inspection of every vacuum hose. Nothing amiss. The intake hoses came off. All good. Checked the CCV pipes, just in case. All fine. Cleaned the MAF despite the fact it was shinier than Kojak's head on a bright sunny day. Pulled the coils and checked the connections. No problems visible there. Injectors seemed fine too.
Then convinced myself I'd swapped the connectors to the solenoids. Until I realised that's almost impossible on the N46.
My code reader is flashing up every code under the sun (not the one shining on Kojak's bonce. Just the regular sun).
And it's still running as though someone had tipped a bag of rock cakes in cylinders 1-4.
In turmoil, I come to the conclusion that I've broken the beautiful girl for good.
A sleepless night follows. And then another one. As the poor car languishes never to move under her own steam again.
And then, out of the blue, I remembered a wise saying from a guru dwelling in the mysterious and magical East (no, not Norwich. Further east than that) which I once heard: 'If it's broken, it's probably something you did to it, you complete plonker'.
And I thought carefully about how plonker'ish I might have been. I'd been concentrating on the solenoid valves as the cause of the engine problems.
But what if it were in fact the steering wheel that was causing the issues. Don't scoff. It's rude. Stick with me on this.
Refurbing the wheel had meant the battery was disconnected for a goodly while. And I figured that this might have something to do with my situation of woe. Uncle Google offered some support. Engine ECUs use adaptive learning, apparently, to iron out all the glitches and make your motor run sweeter than sugar syrup.
So, in polishing up my steering wheel I'd possibly caused the Zed to develop dementia. The old girl's memory had gone. 'Drive the car' said the internet. She'll relearn how to do things. Sounded pretty unlikely to me. But, what to lose? So, I did.
And, do you know what? The old girl has come out of the dementia haze. She's recovering her poise and balance. She is, to sum up, no longer 'bogging'.
The ECU seems to be adapting to its second coming and the car is drivable once more.
So, the lesson is: Even if you think you've terminally broken you beloved Zed, don't despair. The old girl might just surprise you yet.
Meanwhile, I'm off to bed to catch up on two nights of lost sleep. And I've vowed to never do two jobs on the car at the same time. The possibilities for disaster are just too great!
Ian.
 
That's a hell of a tale. Began to wonder if there was a good outcome for a while there.
A valuable lesson learned that if it was working fine before you touched it, there's a good chance you broke it. :wink:

How long was the wheel off for though? Surely lots of people send their wheels away for a refurb? Never heard of them having issues like that?

I assume usually though, they wouldn't be swapping engine parts at the same time? Normally the battery would stay connected for that? So maybe, when the car came round from its anaesthetic it was surprised to find some of it's organs had been changed?
 
I took my time with the wheel refurb, Enuff.
The battery was off for four days in total. The internet has some cases of ECU forgetting settings and rough running as a result but not as many as you'd think.
I reckon I eliminated pretty much all of the obvious things, so I can't see what else it could be really. The engine was getting electricity, fuel and air. Just not in the right amounts so I suppose the 're-learning' stuff makes some kind of sense. Fact is, it was horrid and now it's ok.
I'm guessing here .... but maybe this is a longish time for a battery to be disconnected? Enough time for any ECU back-up capacitor to be drained maybe.
Thank God it's back to normal though now!
 
johnsi02 said:
I took my time with the wheel refurb, Enuff.
The battery was off for four days in total. The internet has some cases of ECU forgetting settings and rough running as a result but not as many as you'd think.
I reckon I eliminated pretty much all of the obvious things, so I can't see what else it could be really. The engine was getting electricity, fuel and air. Just not in the right amounts so I suppose the 're-learning' stuff makes some kind of sense. Fact is, it was horrid and now it's ok.
I'm guessing here .... but maybe this is a longish time for a battery to be disconnected? Enough time for any ECU back-up capacitor to be drained maybe.
Thank God it's back to normal though now!

Yup, indeed. You'll sleep a lot better now. :D
 
It could have been an issue with purging the new solonoids as they come full of air (no extra charge)
Some diagnostic tools enable this, but i guess just running it for a while would also bleed the system & enable correct valve timing again.
Ps, the airbag shouldn’t kill you, probably just a couple of black eyes and a broken nose :lol:
Rob
 
Thanks, Rob. It was properly rough though. If anyone can confirm the adaptive learning process and whether it can be 'lost' it would be interesting to know.
Good to know that the homicidal tendencies of airbags are overplayed! Think I'll still err on the side of caution though :D
 
OMG Ian what a witty and gripping 'tale of woe' !! Pleased to see you solved all your problems and good to know how a change of solenoids might affect the car - it might be me next so thanks for sharing your experience. Look forward to reading your next car related exploits :)
 
That's a great write-up, and I'm glad it all ended well. :thumbsup:
 
When you refurbed your wheel is it possible to remove the sections of trim that go in between the leather too (see pics of my explanation has you confused) I’m too worried to disconnect the battery but I don’t want to remove the airbag incase it sends the screw driver into my face
 

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Hi Gav,
Yes, you can remove the plastic spoke covers. There’s a few guides on the forum how to do it.
I’m not pretending to be an expert here though.....
I disconnected the battery and left it for an hour while I had lunch. Then used a thinnish flat blade screwdriver. You have to poke around a bit (gently) in the hole(s) on the steering wheel mount and you’ll eventually locate a spring that’s resisting you. Push against the spring and pull the centre holding the airbag forwards. It’ll pop off the mounting side by side.
You can then undo the bolt holding the wheel to the column.
The spokes are pretty fragile so be careful. Undo the four screws securing them and gently pry them apart. There’s tabs that need freeing. You’ll see them. Lots of people have found that the mounts for these screws are broken already or break when doing this. Use some epoxy resin if that’s the case.
I’m sure you’ll manage if you give it a try. And if there’s no power to the airbag and it’s capacitor is discharged it shouldn’t kill you.
 
Ps. I forgot. There’s some electrical connectors to free too before you can take the airbag off. Be careful of the single earthing wire. It’s quite delicate. The two small connectors in the airbag itself need to have their sides gently lifted with a tiny screwdriver to free them. The connector to the column just has a tab that needs freeing. Usual type.
 
Great read and glad you got it sorted.

Question - how long did you have the battery disconnected. I am planning to go away and disconnect the battery while I am away for months at end.
In the past when I have disconnected it while doing some work (hour or two max) i have never had such issues as you and I have the same engine. The one thing I noticed is my windows no longer come up on a single press but thats about it.
 
yyz_bobby said:
Great read and glad you got it sorted.

Question - how long did you have the battery disconnected. I am planning to go away and disconnect the battery while I am away for months at end.
In the past when I have disconnected it while doing some work (hour or two max) i have never had such issues as you and I have the same engine. The one thing I noticed is my windows no longer come up on a single press but thats about it.

Have you tried a re teach for the windows?
Rob
 
Smartbear said:
yyz_bobby said:
Great read and glad you got it sorted.

Question - how long did you have the battery disconnected. I am planning to go away and disconnect the battery while I am away for months at end.
In the past when I have disconnected it while doing some work (hour or two max) i have never had such issues as you and I have the same engine. The one thing I noticed is my windows no longer come up on a single press but thats about it.

Have you tried a re teach for the windows?
Rob


Tried multiple versions of

Hold down for 5 , 10, 15 and then back up for the same etc....

My windows lower when i open the door and shut back up. No leaks when using jet wash IT is just that one feature of coming fully up with a single long press.
They go down fine with a long press.
 
yyz_bobby said:
Smartbear said:
yyz_bobby said:
Great read and glad you got it sorted.

Question - how long did you have the battery disconnected. I am planning to go away and disconnect the battery while I am away for months at end.
In the past when I have disconnected it while doing some work (hour or two max) i have never had such issues as you and I have the same engine. The one thing I noticed is my windows no longer come up on a single press but thats about it.

Have you tried a re teach for the windows?
Rob


Tried multiple versions of

Hold down for 5 , 10, 15 and then back up for the same etc....

My windows lower when i open the door and shut back up. No leaks when using jet wash IT is just that one feature of coming fully up with a single long press.
They go down fine with a long press.

Have you tried the re teach with the doors closed?
Rob
 
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