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Discussion Starter #1
Greetings all,

I have got stuck in diagnosing a fault and I'm asking for your guidance and advice!

The Fault:
Misfire on Bank 2 (Nearside UK).

The Car:
June 1999 e39 M5 bought at 149,000 Miles, currently on 166,371 Miles.

Diagnosis so far:
OBD-II results:

  • DME: Misfiring, cylinder 1-8 without cylinder cutout
  • DME: Function, inlet VANOS, bank 1
  • DME: Function, inlet VANOS, bank 2
  • DME: Inlet VANOS, bank 2, advance valve
  • DME: Inlet VANOS, bank 2, retard valve
  • DME: Signal, camshaft sensor, exhaust, bank 1
  • DME: Signal, camshaft sensor, inlet, bank 1
  • DME: Camshaft sensor, bank 1: synchronisation to crankshaft
  • DME: Signal, exhaust-gas temperature sensor
  • DME: Function, oxygen-sensor control, bank 1
  • DME: Function, oxygen-sensor control, bank 2
Results after codes cleared, short drive, re-test:

  • DME: Misfiring, cylinder 5-8 without cylinder cutout
  • DME: Signal, camshaft sensor, exhaust, bank 2
  • DME: Signal, camshaft sensor, inlet, bank 2
Immediate maintenance:

  • Replace all four camshaft sensors at 166,371 found sensors to be the old type, bank 2 exhaust CPS internal seal had gone, full of oil.
Past engine maintenance:


  • Thermostat replacement at 166,371
  • MAF clean and test reading 138 FOT at 164,000
  • Vacuum hose and idle control valve inspect and clean 164,000
  • Inspection II at 160,000
  • Oil and coolant change 160,000 (10w60,BMW coolant)
  • Oil and coolant change at 153,000 (10w60,BMW coolant)
  • Inspection I at 150,000
I have uploaded a quick video to demonstrate the fault here.


After reading up on a vast amount of threads here I have come to a stand still with this issue! Although I have read through this thread. Do you think this is the next logical step to finding the problem?

Thanks for reading, hope someone can help!

Tom.
 

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So what are your current fault codes ?

Is there any leak from B2 Ex CPS now ?

What do you mean the internal seal had gone. Are you referring to the green O ring ?
 

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Since you have cleared the codes has the car been driven, or just idled in the garage? That is a noisy engine, some of it is vanos but some of it must be chains and I have no clue what the one at end when you moved to the back of the engine could be. The thread you linked to talks about resoldering, keep reading, the seals and improving the oil flow are more significant for the amount of noise I hear. I am sure Vantaa M5 will be able to identify each noise and give you some direction. At minimum pull the boards and do the cleaning and seals and solder work, but I think there might be more for you to do.
 

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Discussion Starter #4
So what are your current fault codes ?

Unfortunately I didn't get a reprint of the current codes. As I remember the VANOS issues were not flagged in the 5 mile test drive before the re-test.

Is there any leak from B2 Ex CPS now ?

Nope!

What do you mean the internal seal had gone. Are you referring to the green O ring ?

Not the green O ring but meaning that the old style CPS had a thinner internal unit set in glue within the outer casing. This glue had given way resulting in the sensor filling with oil, you can see from the pictures that oil has flooded in the electrical socket, and no oil was present on the external casing and rubber boot of the cable.

Since you have cleared the codes has the car been driven, or just idled in the garage?

yes it has had a 5 mile test drive to bring up current codes, a small test drive tonight and 4 idle test runs.

I have spent all evening investigating further, I have taken the covers off the solenoids and checked all the electrical joints, had a fiddle around and all "seem" to be fine.

I did notice that upon startup the misfire was present, then after 10 seconds or so the engine jumped quickly to around 1200 revs and then straight back to idle, now it was firing on all 8. A much smoother idle.

Unfortunately after putting everything back together the misfire was present again and has become worse. I went for a short test drive to bring the engine up to temperature and when I returned a new knocking noise became apparent, it was noticeable when letting off the accelerator after a small blip in revs. I've uploaded another video to show this.

"That is a noisy engine," "I think there might be more for you to do." - Couldn't agree more... I cannot find any evidence of the timing chains, rod bearings or any serious VANOS work being done in the service records I have, and the engine has reached 166,000!

So once again the brick wall has decided to build around me.. Any suggestions on threads to read or steps to take would be much appreciated!

Thanks guys
 

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I will give you a link to another post that I posted some pictures done by 68FB of the oil flow. You say you have checked all the electrical on the board, but really you can't while they are in the car. Everything including the MOV (they kinda look like resistors)have to work. Search and search and read and read. Start with the older posts and move to the newer posts. We got smarter so some of the better technics are in the new posts but the bulk of the info is in the old posts.
I think that knock noise from the vanos is from a lack of oil and the piston is smacking into the cover, it all sounds like mine when I forget to plug the board back in. When you are electrically testing the boards use a 9v battery or other source that is of low amps and volts. Testing with a meter is just a waste of time. Start activating the noid at the noid and move one joint out each time until you get to the plug. The thing that will tell you if you have a fault is your ears. Listen and compare the sound each noid makes, anytime the sound is not strong like the others you have a problem there.
I described the cleaning in the other thread so I won't repeat. Use sound to tell you when they are clean also, clean before you do the electric work.
http://www.m5board.com/vbulletin/e39-m5-e52-z8-discussion/200106-vanos-solenoid-seals-vs-piston-seals.html
 

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Discussion Starter #6
Just a quick update.. I have found quite a few common faults with my solenoids, all of which can be resolved with a bit of care and attention. Take a look at the pictures to see whats happened. First of all the gauze on the filters had deteriorated.. Bye bye filters! And one solenoid was not responding at all, took off the tiny PCB and what did I find?!
 

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Assuming your sound files aren't grossly exaggerating the noises, you have a HELLUVA noisy engine. Do you know a shop that is familiar with M5's to help you diagnose? Because it sounds like you may have multiple issues, as you suspect - VANOS dieseling noise, lifter noise, timing chain rattle, quite possibly rod knock. Some listening around with a mechanics stethoscope (cheap and useful) will help.

If that doesn't help and you want to fix it yourself, you can narrow the possibilities down by attacking the various causes in order of ease of repair - VANOS board/solenoid valve rebuild, new main timing chain tensioner, new VANOS diaphragm washers and chain guides/tensioners. Quite a daunting list. Good luck.
 

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Discussion Starter #9
A daunting list it is! But I enjoy working on the car so I will be attacking each problem bit by bit. Unfortunately living in the north west of England there aren't any garages that are completely familiar with the e39 M5, however I have been considering a road trip down south to have Phil Crouch at CPC Performance Engineering Ltd have a look a it.

I have pulled the VANOS solenoids this weekend to clean and repair what I can and have ordered new seals to finish the job this week.
 

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One problem area with the solenoid boards I have seen talked about a lot on here is the earlier cars like yours not having an effective way of keeping the solenoids valves pressed firmly onto the steps in their bores which allows them to chatter backwards and forwards, causing wire, solder, and PCB flexing and fatigue. Check the boards very carefully for these problems. The DIY's explain how to check the SV function with a 9 volt battery but sometimes that does not pick up an intermittent circuit break.
The fix seems to be to switch to the newer style board covers which have set screws that clamp the SV's down.
 

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Think gzig just drilled and tapped his old covers to make them look and work like the new ones. No review yet. Since he has not posted another thread about fixing his boards I suspect it works.
 

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Discussion Starter #12
Indeed that has happened with my solenoids, I have attached pictures to show what I came across in regards to them moving in and out. One SV had a snapped terminal, one had it's feed wire chaffing against the SV and in general the soldering looked fairly weak, no dry joints but re-soldering all the connections will help to stop that. And finally I spotted some very odd residue above the tiny PCBs on the covers, I can't explain what has happened there except for wear and tear.

That is a very good idea you've brought up Sailor24, I can imagine 8 grub screws around M8 or M10 in size with some thread lock would do the trick. I will have a look into doing it!
 

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Wow, what a mess. Fixing all that up should really improve things.

That characteristic ochre red dust is the product of "fretting corrosion", probably from the tops of the steel solenoid bodies. It happens when dry steel parts vibrate against other parts with very small movements.

I would imagine that SV movement would also cause significant wear of the o-rings. They are just supposed to be static seals.

Drilling and tapping for grub screws sounds like a great idea. TIS provides the torque required for these to securely clamp the SV's. I would make sure the ends bearing on the SV's are at least the diameter of the later style grub screws and the ends are dead flat to spread the load.
 

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Discussion Starter #14 (Edited)
Bit of an update and a question here, I have had a look at the online BMW TIS manuals and found that there is a comment on different SVs being pretensioned and not pretensioned.

Seeing as I will be modifying the covers to resemble the later model. Are my solenoids any different or are they making a valid point here? I do not want to end up breaking my SVs.

I have sourced the necessary parts and tools to do the job and if it wont actually harm the older SVs, I will write up a DIY for other people to benefit from the modification.
 

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The comment is just that some can't be tensioned. I did not see anything that says the solenoids are different, and I have not heard they were, just the covers are different. As long as your grub screw is larger than the dot in the center of solenoid I don't see a problem. I have repaired boards on 99 and never noticed a different solenoid. The boards come alone in the mail so I don't see the other part. I have noticed different #s stamped in the top and on some the dot is a different color, none of that seems to relate to specific years. My guess is the differences is do to suppliers, but I am only surmising.
 

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Discussion Starter #16
I see, I did notice different #s looking at other solenoid pictures, and that's what made me think are they different? I shall carry on as planned and update once done!
 

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I was thinking about this as I drove home and I have to admit I don't pay that much attention and I only have one set of boards at a time. Each board that has unknown issues that are not apparent goes in my car first and last for testing and codes. I think I would have noticed then. Most boards the problem is apparent so they just get repaired and tested in my new rig.
If you wanted to be safe, just don't torque the grub screws as much.
 

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Discussion Starter #18
Another update, I have re-soldered and tested all my solenoids. One of which will not respond at all and has 0 Ohms.. I'm taking a guess that there is nothing I can do with it and require a replacement. Can anyone help in sourcing a single solenoid? Maybe from a second hand board. I'm reluctant to buy a new set as I can easily replace one.
 

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Another update, I have re-soldered and tested all my solenoids. One of which will not respond at all and has 0 Ohms.. I'm taking a guess that there is nothing I can do with it and require a replacement. Can anyone help in sourcing a single solenoid? Maybe from a second hand board. I'm reluctant to buy a new set as I can easily replace one.

Contact Phil Crouch of CPC Performance Engineering : CPC Performance Engineering

He should be able to send you a spare one. Or if you send him your board he maybe able to get all 4 solenoids working and sent back to you ASAP..
 

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Another update, I have re-soldered and tested all my solenoids. One of which will not respond at all and has 0 Ohms.. I'm taking a guess that there is nothing I can do with it and require a replacement. Can anyone help in sourcing a single solenoid? Maybe from a second hand board. I'm reluctant to buy a new set as I can easily replace one.
I find measuring 0 ohms across the solenoid coil a bit surprising. That suggests the coil has a wire-to-wire short internally, which in my experience is unusual. The more common failure mode is a broken/burnt coil wire which gives an open circuit i.e. infinity ohms. A true resistance of 0 ohms would draw a lot of current from the testing supply.

How did you measure the resistance? If you haven't already, I suggest completely desoldering it from the board so you can measure the resistance directly across the two potted pins. That way you rule out a shorted MOV, a solder bridge somewhere, etc. I would want to be 100% confident the solenoid was bad before going through the hassle of replacing it.
 
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