E60 550i pinging - driving me up the wall!

[fritz.hu 2]

Hi all,

I have a 2006 E60 550i running the N62 4.8 V8, 6spd auto. It has 140,000kms.

It runs beautifully when cold, great on the highway, pulls like a demon - but around town after a highway run, it pings like mad and seems to not pull so well anymore.

I've done the following:

• Replaced crankshaft position sensor (verified to be bad)
• Replaced all four camshaft position sensors
• Cleaned VANOS solenoids
• Set of brand new coils
• Set of brand new plugs (old ones had carbon-looking stuff bridging the electrode and ground)
• Verified engine temp (upper hose) is 105'C (was not pinging at the time however)
• Transmission fluid changed twice with new solenoids (unrelated, but in case)
• New crankcase vent valves
• New MAF sensor
• Many, many bottles of total fuel system cleaner run through the tank
• Can of foaming carbon cleaner through the PCV hose
• Flashed with latest firmware for all modules except CCC
• Strapped exhaust butterfly valve open to eliminate it as a false-positive
• Can of start-ya-bastard sprayed around the engine and its components to check for vacuum leaks
• Didn't find anything with a full INPA and GT1/DIS and ISTA/D setup

What I'm going to try next:

• Build an Arduino datalogger to see if engine temperature goes much over 105'C when it actually pings
• Pull and re-check spark plugs
• Pull and check fuel injectors (??)
• Pull IVM and try resoldering the DME relay contacts (some claim this is a common issue, but symptoms are normally worse than what I am seeing)
• Verify intake air temp sensor
• Replace heater control valves (I get little to no warm air with the system on heating)

Anything else?

HELP!!  this thing is driving me nuts!

[*Glenn* 855]

Does it use oil? and has it been checked for valve stem seal issues?

[aja540i 1906]

what fuel do you use? my m5 does it as well and i suspect ionic current detection module is dying (or dead) but i don't think yours has one? I find mine seems to come and go with gas from different suppliers, but haven't managed to nail down which one (if any) is causing the issue for sure yet.

[*Glenn* 855]

10 years old and over 100k these things become money pits. I have a X5 4.8 2007 done a 140k in the workshop at the moment which requires more than the value of the vehicle to repair. The original oil leak problems would have cost close to 1/2 the value of the vehicle. We also have another client with a 550 with exactly the same problem as yours and several well recognized repairers and a dealer can't fix. It has a warranty and the customer is resigned to drive it till it breaks.

[fritz.hu 2]

Hi Glenn,

It doesn't seem to use oil - it has an intermittent issue with the level sensor though so I just check using the dipstick instead. It's nice and stable, I don't need to add oil between services (I do them at 15,000kms)

aja540i, I always use 98, usually from Mobil but occasionally the E10 blend from Gull as well. Pinging doesn't seem to get worse whatever octane I use though.

It's almost as if it isn't pinging - but then, it only happens at low RPMs when the car is warmed up and under load... but at the same time, it occasionally does it at 3000RPM too - you'd think pinging wouldn't happen at that speed...

[*Glenn* 855]

We have also had it occur in the workshop without load at about 1,500 -2,000 rpm. It does sound like chain rattle at times. Has been checked by dealers and independents  without resolve .Warranty  company also involved. When it breaks it might get fixed or write it off. In the mean time.... he hits the go peddle and enjoys it while he can. 

[Matth5 471]

"Build an Arduino datalogger to see if engine temperature goes much over 105'C when it actually pings"

Seems overkill. Use Toque (Android app) to log it and then you can use datazap.me to see an interactive graph. Much easier...

[fritz.hu 2]

Okay, some progress... maybe.

When I did the plugs and coils approx 5000km ago, I did notice the back two - 4 and 8, incidentally the hardest to get at - had never been replaced - the BMW dealer where this car was bought was the last and only place in the service booklet to mention replacing plugs (!!). The plugs themselves were carbon bridged. Didn't think too much of it at the time (also !!).

Fast forward to today. I hooked up INPA and went for a drive, keeping an eye on the knock sensor readings. whenever it pinged, guess which ones spiked right up? Yup, 4 and 8.

So, my plan now is to acquire an endoscope, then pull the plugs and see what's going on in there. Maybe fit a couple of steps' colder plugs while I'm at it.

Any ideas whether colder plugs will actually harm the engine or not? It's specced to have NGK heat range 6, I'm thinking 7, or maybe 8.

 

[BreakMyWindow 1878]

Could be a slight breach of the head gaskets, compression and leakage tests??

[kwhelan 241]

possible heat difference around the back of the engine due to water flow?

[fritz.hu 2]

Thanks guys, definitely some good points to check!

I'll do a compression test soon but I don't have a leakdown tester. It doesn't display any typical headgasket symptoms but I wouldn't rule it out.

Re heat difference, I will give it a good drive and then use the IR thermometer to check the temp difference between the front and back of the block. According to this document (http://www.internetsomething.com/lpg/01_N62 Engine.pdf) the rear cylinders would be receiving cool water first, so it would have to be a strange kind of blockage to allow the front cylinders to be colder...

[fritz.hu 2]

Okay, so found some things today.

1. Pulled the spark plugs. All looked very good.
2. Compression test returned 195-205psi on all eight cylinders.
3. Poked a borescope down in there. There is some relatively significant carbon buildup but not too extreme.
4. While cranking for the compression test, heard a significant hissing noise from the brake booster.
5. Located the hiss to one side of the booster, on the opposite side from the vacuum line.
6. Thought, "Ah, that's gotta be expensive."
7. After putting everything back together, started car and let it idle.
8. Pressed brake pedal with constant force - it sinks deeper and deeper until practically to the floor.
9. Let go of pedal, idled for a minute or two, then turned off car.
10. After waiting around 2 minutes, pressed brake pedal expecting some vacuum assist, but there was none. Vacuum had gone in those 2 minutes.
11. Went on Pelican Parts and found out, "Hey, that's not actually so bad."

So - a couple of questions for anyone who knows:

• Brake booster vacuum leak - is that a common occurrence with the E60?
• Would a leak that dissipates the vacuum held in the booster in less than 2 minutes be significant enough to affect how the engine runs?

Edited June 3, 2017 by fritz.hu
Fix a typo

[BM WORLD 1286]

they have a little vacuum pump on the engine to make vac for the brake booster ,

they have seals and o-rings which fail after a while ,

worth checking them

http://bmwfans.info/parts-catalog/E60/Europe/550i-N62N/R-N/2006/browse/engine/vacuum_pump_with_tubes/#7545384_1

 

also check for oil in the lines .

you can open these units up

 

[fritz.hu 2]

Nice, that's really good to know - thanks!

This leak is on the booster/servo itself, though - does anyone know how big a vacuum leak has to be before it starts causing things like an occasionally-hunting idle and pinging on these motors?