B5 Limp mode

[Grumpyjohn1957]

Post moved here as it's probably a more suited forum.

Sat Jul 10, 2021 11:04 pm

ScooBeeFive wrote: ↑Not good..... Hope it's nothing too serious but it doesn't sound great. Are you able to get it in anywhere to be checked out?

Yes OK, thanks for asking Paul.
Bit of an odd one, had a service two weeks ago, oil, plugs, filters, VHC etc & all good. Since have noticed a faint whiff of petrol on occasion. Anyway, up to northeast Scotland, tank & half V power low/mid 30s mpg. Yesterday thought MPG had dropped off slightly. Coming down A1 this afto’ decided to take the scenic route via Banburgh, topped up with 55lts Esso just prior to B1342 turn. Five mins later power disappears, starts rattling, rumbling, popping and shaking like a ba@#?rd, dash lights up. Limp into village, park up, turn off.
Restart, still rough but a bit better, switched off completely, locked and left for 10 mins to say a few quick prayers.
Restart, all good again but displaying fault under notifications on iDrive. Gingerly back on A1, throttle didn’t feel totally responsive but all smooth and quiet. 5 mins later notification clears itself and the beast is back. Last 250 miles home, mpg good, smooth, and fully responsive again.
Sytners next week and get the codes read
.

Addendum: Having slept on it I seem to recall BM fuel tanks are pressurised? If so how is the pressure generated and controlled? Venting of the tank would account for random petrol odours and pressure loss would effect fuel flow?

[Charles]

Perhaps fuel starvation caused by partial blockage of fuel pump/filter? Leaving it to stand/settle may have improved flow again.

[ScooBeeFive]

Glad it cleared after and you weren't left stranded. The prayers were answered! Does sound potentially fuel related - be interesting to see what the codes say.

[hashluck]

Perhaps fuel starvation caused by partial blockage of fuel pump/filter? Leaving it to stand/settle may have improved flow again.

I was thinking the same. Oh and check fuel cap refitted correctly

[Grumpyjohn1957]

Hopefully Charles it will be that simple!
Followed a link Bob posted sometime ago and had a read of the parts manual.
I'll take her into Sytner Notts during the week & see if they can find a fault code.
The petrol smell is the really concerning bit.

[hashluck]

The petrol smell is the really concerning bit.

Check the fuel cap is correctly fitted

Or you possibly over-filled?

[Grumpyjohn1957]

Cap fitting correctly, definitely not overfilling the tank.
The petrol smell (infrequent but briefly pungent) only occurs on over run after a very short squirt of power or brief throttle dab.
Carrying an extinguisher with me tomorrow!

[Bob]

Sorry to hear about your woes. Fire extinguisher sounds prudent given the circumstances, but hopefully unnecessary.

[Grumpyjohn1957]

Not sure which is worse, a poorly pet, family member or Alpina!

Before dropping her in to the dealers I got a local Indie to take a look. To be forewarned is to be forearmed as it were.
In the indies opinion, the problem is on the left bank injector rail.
ISTA reports the problem as combustion misfires on 5 & 8 with injection shutoff, little wonder it started running rough! The fault list then goes on to show the subsequent turbo shut off (limp mode) on my first restart attempt and then nothing more.
Apparently, when the car was locked and abandoned it was long enough for it to go to sleep and reset itself.
The chap who did the check is extremely knowledgeable and experienced with S62/3/4 engines to which the B5s N63TU3 M3 is similar. He suggests it’s all down to a little pressure sensor tucked away in the injector rail playing up. The symptoms described match those he has seen on V8 cars many times. His advice was “let the dealers sort it with Alpina and insist they change, under warranty, both your oil and catalyst as they may have been damaged by raw fuel”.
The dealers take on this?
Actually I have some empathy with the staff, when you push them, they really do try to go the extra mile and today was no exception.
The BMW diagnostic involves plugging the car in and Munich’s computers then directly execute a pile of diagnostic routines examining all the various inputs and outputs from sensors whilst crosschecking the cars software is interpreting and executing that data correctly.
The car sits in the workshop hooked up to fans and tubes revving it’s “nuts” off and doing strange things whilst the Techies carry on with their day jobs! All they see is a progress bar creeping across a screen, not dissimilar to installing windows.

Anyway, long one short, after 2 hours the PC crashed so no results. I couldn’t believe it, but Hey ~#@t happens.
The techie in question was quite apologetic – not his fault – and after a very lengthy & detailed discussion about engine management systems he went on to say; these cars are so rare we don’t get to work on them very often and therefore can’t second guess problems.

She’s going back end of month for a 2 day stay which hopefully will resolve matters.

Whilst I was there took the opportunity for a brief chat with Gary Lott. Gary took great pride in showing me the latest deliveries, B5 LCI Touring in Green, Tanzanite B3 Touring, B8, XB7, clocked V10 CCH in the handover bay amongst others. -- Test drive bookings to be made shortly, consulting wife & bank manager in due course!

Meantime car drives as she always has and I fully intend to continue enjoying my superlative piece of automotive engineering to the max.

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[Grumpyjohn1957]

It could be said a day without your Alpina is like a Day without Sunshine.
I’m dreading what comes next, the nights are drawing in.

When Brunhild went to the automotive vets for her tests I got to knock around in a Mini Cooper for a couple of days.
Turned out to be quite a Cheeky Chappy with a big personality all its own.
Wafting, purring, and catapult launching on demand it didn’t do.
Driving one to the Alps is something I certainly would not entertain but that said, it’s sense of immediacy with a penchant for delicately sipping petrol as opposed to guzzling weighed in its favour.
The one thing it did excel at was making me appreciate what amazing machines Alpina build.
How lucky am I to have one of the last ICE V8s?

Anyway, back to the diagnostic, the bottom line of the two days diagnostic work is: The car experienced misfiring, cut out and logged it as a fault.
Sytner can’t see why, with no other faults recorded before or since, everything checks out good.
The engine management software got reloaded as part of the process (whatever that involved)
Everything then got rechecked and was shown to be within parameters, so it was a case of “Here’s your car back sir”.

My fingers were crossed it was just one of those things, I said thanks and drove away.

Meanwhile all the recovered engine log files got sent to Alpina for further analysis.

Two weeks plus elapse.

Today I get a phone call.
A cheery female good morning voice says. “Good morning sir, sorry to call you so early, Alpina have requested we conduct further tests on your vehicle”.
“Yeah, like what?” Comes my gruff reply.
“They’ve asked us to check the cylinder bores for scoring and a couple of other things.”
Me: Oh yes, what other things might that be?
“I don’t know without asking the service manager sir. Hopefully we’ll only need the car for two days, although if we find something it could be much longer (pause) but don’t worry I’ve asked BMW if they’ll lend you a more comparable vehicle for a few weeks instead of one of our minis.”

Me: under breath, f’#~ing hell, weeks, this don’t sound good.

So, there we have it, the borescope for Brunhilda beckons.

Can’t fault Alpina for customer care over this. Talk about pride in their engineering or what.
The dealers are being pretty good about it too, so much respect where due.

Having read up on the N63TU engine I can see why Alpina are tetchy. The bores are weld sprayed to create a wear coating on top of the Alusil. Damage that and you’ll soon be burning aluminium in addition to petrol.

I guess the theory goes neat fuel washes the oil off then it’s metal on metal time. (With all the accompanying enjoyment that brings)

Brunhilda’s been changed every 8000 with the correct long life 0-30 stuff, that’s 3 changes in under 12 months! I’m about to find out if it was a good move or waste of money.

As much as I’d like a new engine, I can think of better ways of going about it!

I’ll finish for now by strongly suggesting to any potential “used” purchaser of one of these cars that the importance of a history showing correct oil and filtration changes with greater than spec’d frequency is absolutely paramount.

The same might well apply to the cooling circuits. Periodic D.I water flush and refill with factory grade coolant. If not your Alpina might quickly go the way of a neglected 992 Porsche e.g., furred up cooling galleries and a knacked block.

[Jonnywishbone]

I hope the problem gets diagnosed and resolved to your satisfaction John. I have nothing to add on the technical side of things.

However, since you are going to be deprived of such an exceptional machine for perhaps an extended period, I might be minded to take the dealer very literally at their word. More comparable vehicle? The only thing in the main BMW line up that comes even vaguely close is an M5!

[Bob]

Does sound like worrying times for the old girl. Is that the automotive equivalent of a proctological exam?

Here’s hoping for the all clear.

[hashluck]

Following with interest, hope all will be OK. Good to see Alpina stepping up

[davettf2]

Interesting, is this a new way of describing 'Nikasil'. Worrying that high sulphur gasoline combined with a colder running engine will destroy it. Not sure where the modern Ethanol fuels fit in but can understand why they want to poke around in the engines inner regions. Although given that you appear to cover high mileage significant cool running should not be an issue, unless lots of start / stop driving. Will be interested to hear the outcome.

Cheers
Dave

[Grumpyjohn1957]

Things have moved on.

Today, I received a phone call from Sytner advising me that the scheduled Borescope examination of the cylinder bores is no longer required.
Alpina will be replacing the entire engine under warranty.