B5 Misfire - The Unofficial BMW M5 Messageboard (m5board.com)

Heuer · 16th February 2006, 22:04

On two occasions my B5 has misfired badly. The car started from cold and after about 4 minutes of driving, under light acceleration from 2k revs to 3k the engine coughed, warning light came on and power dropped dramatically. Starting the car cleared the problem. On the second occasion I was leaving the dealer after they had checked everything. Managed to limp back and diagnostics showed 'engine misfire' but no cause.

Car was back to dealer today as Alpina engineer was there. They are puzzled, think it is mechanical rather than software/electronics and have downloaded all metrics back to Buchloe. Current thinking is it may be a known problem with BMW V8 cylinder heads. Seems there was a batch of rocker arms out of spec and 545/550i's have exhibited the problem. They are not sure if Alpina heads were affected although they are standard BMW items.

Anyone heard of similar problems with either B5's or BMW V8's?

hythe · 16th February 2006, 22:34

Axel's swinging by tomorrow to come do our reprogramming - he mentioned it's to do with the DSC, but I'll see what else I can glean from him while he's here...

zaki · 17th February 2006, 01:23

It doesn't sound very good.

Could be electronical or could be mechanical problem. Due to the fact that Your car is new electronical makes more sense but who knows

P.S. I 'm about to become B5 owner very soon and I did not want to hear this

hythe · 17th February 2006, 08:47

Quote:

Originally Posted by waygadoo

It doesn't sound very good.

Could be electronical or could be mechanical problem. Due to the fact that Your car is new electronical makes more sense but who knows

P.S. I 'm about to become B5 owner very soon and I did not want to hear this

Cheer up - I haven't had a single problem with mine, in 4 months and nearly 4000km

Heuer · 17th February 2006, 12:39

Quote:

Originally Posted by waygadoo

It doesn't sound very good.

Could be electronical or could be mechanical problem. Due to the fact that Your car is new electronical makes more sense but who knows

P.S. I 'm about to become B5 owner very soon and I did not want to hear this

Agree with hythe - the B5 is a superb car and the service I have received from Alpina and the dealer has always been excellent. This has only happened twice in 4,000 miles and under the same conditions. They are on the case and will solve it I have no doubt.

It is most definitely not an electronic problem as the computer knows there is a fault but not why. Basically sensor detects unburnt fuel in the exhaust and immediately closes down the cylinder involved (it knows which ones) to prevent damage to the cat. In my case it was cyls 2,4,6,7 & 8. The car will not activate them again until ignition is switched off. When it restarts and finds no fuel in the exhaust it carries on as normal. Fault is affected by temperature hence the theory there are some parts out of spec - they change size with heat. Although two thirds of the B5 engine is different from the BMW V8, the variocam heads are standard. Hence my question if any E60 BMW V8 owners have noticed a problem. My dealer says they have already done several 545i's but I can find no information on any forums.

zaki · 17th February 2006, 13:51

You're wright. No need to panic at all.

P.S. My firend beat me to it. He got his Bmw (Individual RubinBlack) M5 before me getting my B5. He'll brake my balls every single day until april.

zaki · 17th February 2006, 17:24

Hythe/Heuer, what engine oil do You use?
How do You find the car when driving fast in the rain?

Heuer · 17th February 2006, 18:30

Whatever it was delivered with. They do supply a top-up bottle in the wheel well but I have never had to check the oil as yet.

Car is effortless to drive so rain is not a problem as long as you are aware how much power is under your foot. Alpina have just recalibrated the DSC on the Tourings as they were delivered with the settings for the 545i by mistake! This made the car a bit of a pain to drive as the electronics kept intervening (my best effort was traction control coming on at 117mph) and under hard acceleration it would suddenly back off. Have not driven it very much since the upgrade but it has transformed the car under hard acceleration. Saloons were not affected.

stefan1 · 17th February 2006, 18:48

Alpina seem to specify Castrol SLX 0/30, which is the same oil as for most BMW engines. It is a "thin" oil suitable for an engine manufactured to very tight tolerances.

As for driving in the rain, well I tried the car with no DSC (the "all the way off" setting!), and let's say it was exciting. I had the classic power oversteer out of a tight roundabout, but it was delightfully controllable. Not sure if the Mondeo man behind was applauding or giving some other signal afterwards!

I will be taking the car to the Ring soon (I race over there in the VLN) and I look forward to putting the chassis to the test - it is quite soft of course, but my sense is that it has real depth of ability. The Ring will be the place to test that hypothesis!

Kind regards

Steve

zaki · 17th February 2006, 20:06

Exactly what I wanted to know. Thanks a lot guys.

Quote:

Originally Posted by stefan1

Alpina seem to specify Castrol SLX 0/30, which is the same oil as for most BMW engines. It is a "thin" oil suitable for an engine manufactured to very tight tolerances.

As for driving in the rain, well I tried the car with no DSC (the "all the way off" setting!), and let's say it was exciting. I had the classic power oversteer out of a tight roundabout, but it was delightfully controllable. Not sure if the Mondeo man behind was applauding or giving some other signal afterwards!

I will be taking the car to the Ring soon (I race over there in the VLN) and I look forward to putting the chassis to the test - it is quite soft of course, but my sense is that it has real depth of ability. The Ring will be the place to test that hypothesis!

Kind regards

Steve