BMW M5 Forum and M6 Forums banner

1 - 12 of 12 Posts

·
Registered
Joined
·
666 Posts
Discussion Starter #1 (Edited)
Im in the process of tracking down the cause of a Vanos low pressure issue and came across this; figured i'd share for those of you who don't have access to ISPI/ISTA. It requires a high pressure test gauge capable of reading 100 bar, but a quick visit to Amazon can solve that for about 65$.

To supplement this, there is also a little "trick" you can do to activate the VANOS accumulator with engine off which charges the VANOS lines with ~70 bar which can be monitored with your pressure gauge for a static pressure drop which will identify whether or not the internal HPOP line in the crankcase is leaking. In many of our PuMA cases, the dealers wanted to replace the pumps AND the line claiming it was "impossible" to isolate the line. :tonquesmilie::3:hmmm


The pressure test of the VANOS system checks the pressure generation and leak-tightness of the VANOS system.

Test preconditions:

- Engine at idle speed

- Engine oil temperature > 80 °C


System overview:




1) Connection to cylinder head

2) Banjo bolt for connection of the adapter and of the sensor

3) Connection to cylinder head

4) High pressure line in the crankcase

5) VANOS oil pump

Test procedure:
Connect the pressure adapter and the sensor to (2)

Measure the VANOS oil pressure

- If the oil pressure is OK:

No other measurement necessary, oil pressure in the system OK

- If the oil pressure is not OK:

Continue measurement with point 3


Loosen and close the high pressure lines at both cylinder heads, (1) and (3)

Measure the VANOS oil pressure

- If the oil pressure is OK:

Continue measurement with point 5

- If the oil pressure is not OK:

Check the following fault causes:

External leak on the VANOS system

VANOS oil pump

High pressure line (4)

If there is no external leak, check high pressure line for leak-tightness: Apply compressed air to the high pressure line (approx. 8 bar) (oil pan removed).

If the high pressure line has no leak: replace VANOS oil pump.


Connect a high pressure line to a cylinder head, (1) or (3)

Measure the VANOS oil pressure

- If the oil pressure is OK:

Internal leak in the VANOS system of the cylinder head that is not connected

- If the oil pressure is not OK:

Internal leak in the VANOS system of the cylinder head that is connected


Other troubleshooting if a leak was detected on a cylinder head:

- At the cylinder head concerned, remove the VANOS solenoid valves

- Check the O-rings of the VANOS solenoid valves

- If the O-rings are OK: replace the VANOS adjustment unit of the cylinder head concerned

- If the O-rings are not OK: replace the solenoid valves concerned
 

·
Registered
Joined
·
666 Posts
Discussion Starter #3 (Edited)
So I managed to do some testing today and have a question for some of the more experienced guys:

Does anyone know if there is a check valve/bleed valve in the VANOS system which would explain the loss of static pressure aside from a bad pump or high pressure line?

My goal with this test was to try to identify an internal leak simply by means of monitoring the static pressure drop using the oil.

I have 75 bar pressure @ idle with no spikes, drops, or other issues, so dynamic oil pressure with the pump running is correct.

The reason I ask is, with engine off, but accumulator manually activated I have a static 70 bar which steadily drops to 0 within about 30 minutes. If there is no bleed down valve in the VANOS system, this would be theoretically indicative of a leak somewhere. I just wanted to make sure before I start jumping to any conclusions. Obviously the sole purpose of the accumulator is to pre charge the VANOS system @ start which would indicate this is normal, or there would be no need for the accumulator, right?

After ~10 mins (dropped to 40 bar)



After ~20 minutes:



And finally after ~25 mins



Again, this is with engine off, and accumulator manually activated by putting 12v on pin 24 (DME) to accomplish static oil pressure for testing purposes.
 

·
Registered
Joined
·
362 Posts
I say replace the vanos line. And of course do the rod bearings while you got the pan off. Problem solved, and much more peace of mind.
 

·
Registered
Joined
·
991 Posts
One thing often neglected, and depending on your condition - the VANOS accumulator. These can wear over time and lose pressure holding capability rather quickly if internal seals are worn out. It sounds like you lose pressure with the engine OFF and static - do you also have a low pressure condition when the engine is running? At start, some (myself included) will get a code (not a CEL, just a DME code stored) for low vanos oil pressure. This triggers immediately after start as the system checks a low pressure condition momentarily. If you are having issues, like increased emissions, etc - then progress your trouble shooting to parts replacement.

Also, perform a VANOS test and bleed system regularly. In order of part-chucking, I'd start with the easy cheap stuff first... VANOS accumulator (which really isn't necessary, just reduces rattle at start and the momentary low pressure condition). Throwing pumps and lines at it is VERY costly and may not even cure your problem. Just an FYI...
 

·
Registered
Joined
·
666 Posts
Discussion Starter #6 (Edited)
One thing often neglected, and depending on your condition - the VANOS accumulator. These can wear over time and lose pressure holding capability rather quickly if internal seals are worn out. It sounds like you lose pressure with the engine OFF and static - do you also have a low pressure condition when the engine is running? At start, some (myself included) will get a code (not a CEL, just a DME code stored) for low vanos oil pressure. This triggers immediately after start as the system checks a low pressure condition momentarily. If you are having issues, like increased emissions, etc - then progress your trouble shooting to parts replacement.

Also, perform a VANOS test and bleed system regularly. In order of part-chucking, I'd start with the easy cheap stuff first... VANOS accumulator (which really isn't necessary, just reduces rattle at start and the momentary low pressure condition). Throwing pumps and lines at it is VERY costly and may not even cure your problem. Just an FYI...

Good point. My issue is noise, and all the BMW documents I have including some engineering level stuff and PuMA cases indicate noise is cause by lack of oil pressure. My personal testing contradicts this. I have no oil pressure issues running, or at startup but I still have VANOS noise during cold start when the cams are at full advance, and when tipping the throttle only in M mode when the engine is at temp. (tipping the throttle at idle, the VANOS actuators both rattle momentarily like clockwork as soon as the throttle is tipped lightly.)

I have manually confirmed proper accumulator startup pressure with the valve open my manually tapping in @ DME to activate it. All is OK...

I have no codes, only noise. All 4 solenoids fail the VANOS tests, that's all I have so far. Before I went at it with 4 new solenoids, I figured I'd make sure there were no oil pressure issues and this would logically explain the failure of all 4 solenoids since oil pressure is a common denominator with all of them.

I ran the vanos bleed 4 times consecutively to isolate air as a possible issue, and no change was noticed.
 

·
Registered
Joined
·
5,673 Posts
Good point. My issue is noise, and all the BMW documents I have including some engineering level stuff and PuMA cases indicate noise is cause by lack of oil pressure. My personal testing contradicts this. I have no oil pressure issues running, or at startup but I still have VANOS noise during cold start when the cams are at full advance, and when tipping the throttle only in M mode when the engine is at temp. (tipping the throttle at idle, the VANOS actuators both rattle momentarily like clockwork as soon as the throttle is tipped lightly.)

I have manually confirmed proper accumulator startup pressure with the valve open my manually tapping in @ DME to activate it. All is OK...

I have no codes, only noise. All 4 solenoids fail the VANOS tests, that's all I have so far. Before I went at it with 4 new solenoids, I figured I'd make sure there were no oil pressure issues and this would logically explain the failure of all 4 solenoids since oil pressure is a common denominator with all of them.

I ran the vanos bleed 4 times consecutively to isolate air as a possible issue, and no change was noticed.
What specifically are the solenoids failing on? spread times? null current? Or just the "quality" factor? The last is a joke and disregard it, the other values are all that matter. If the spread times are out of tolerance, leak-by on the solenoid cartridge and/or cartridge spool is one possibility for pressure loss, but IMO not very likely in comparison to low pump discharge output or a leaking high pressure line.
 

·
Registered
Joined
·
5,673 Posts
Adding here for reference, originally posted in another thread

So I had an epiphany regarding the DME's VANOS low pressure errors last night.

The DME has no idea what VANOS pressure really is. None. Not Possible. Having taken apart more than a few now, I don't know why I never realized this sooner. There is no pressure sensor on the S85 VANOS high pressure oil system. If there was, the ISTA/D diagnostic routine for measuring pressure wouldn't have to connect a pressure transducer on the "T" fitting to carry out the diagnosis, it would just poll the DME for the pressure reading.

So, what causes this code then?

It seems to me that the only way the DME would know if pressure was low is if the VANOS actuators were adjusting timing at a slower rate than expected. This would lead the DME to interpret that as low control oil pressure, this triggering the code.

What does this mean?

I had this on my car 3 years ago, only on very, very cold Maine winter mornings. When my injector failed and I opened my bottom end, I replaced the VANOS pump, the high pressure line, the rod bearings, and switched oils. I also replaced 3 of 4 VANOS solenoids before I started the engine back up. This doesn't help in diagnosing at all, but I never saw the error again. I never received it during any summer months before either.

I know the VANOS pump wasn't the fault, I replaced it with a brand new one to upgrade the gears and my old one is running merrily around in another engine for 25k miles now.

It's possible the VANOS HP line was at fault, or I believe more likely is the VANOS solenoids.

It's amazing we (collectively) have never realized/discussed this before. It really has to make you wonder how many BMW techs over the years could have been lead down the path of pump/line replacement when really the solenoids could have been at fault. Often it accompanies two VANOS bank actuator errors and I know they love to replace those.

Just something I figured I should add to this thread. Still trying to work out the mechanics of the error in my head.
 

·
Registered
Joined
·
67 Posts
Sorry for reviving an old thread.

I am trying to build a test tool to check the condition of my pump (car isn't running properly). I am trying to find the size and thread of the banjo bolt so that I can buy a couple one and have a high pressure line made up to connect it to my pressure gauge.

Thanks for any help if you can.

Im in the process of tracking down the cause of a Vanos low pressure issue and came across this; figured i'd share for those of you who don't have access to ISPI/ISTA. It requires a high pressure test gauge capable of reading 100 bar, but a quick visit to Amazon can solve that for about 65$.

To supplement this, there is also a little "trick" you can do to activate the VANOS accumulator with engine off which charges the VANOS lines with ~70 bar which can be monitored with your pressure gauge for a static pressure drop which will identify whether or not the internal HPOP line in the crankcase is leaking. In many of our PuMA cases, the dealers wanted to replace the pumps AND the line claiming it was "impossible" to isolate the line. :tonquesmilie::3:hmmm


The pressure test of the VANOS system checks the pressure generation and leak-tightness of the VANOS system.

Test preconditions:

- Engine at idle speed

- Engine oil temperature > 80 °C


System overview:




1) Connection to cylinder head

2) Banjo bolt for connection of the adapter and of the sensor

3) Connection to cylinder head

4) High pressure line in the crankcase

5) VANOS oil pump

Test procedure:
Connect the pressure adapter and the sensor to (2)

Measure the VANOS oil pressure

- If the oil pressure is OK:

No other measurement necessary, oil pressure in the system OK

- If the oil pressure is not OK:

Continue measurement with point 3


Loosen and close the high pressure lines at both cylinder heads, (1) and (3)

Measure the VANOS oil pressure

- If the oil pressure is OK:

Continue measurement with point 5

- If the oil pressure is not OK:

Check the following fault causes:

External leak on the VANOS system

VANOS oil pump

High pressure line (4)

If there is no external leak, check high pressure line for leak-tightness: Apply compressed air to the high pressure line (approx. 8 bar) (oil pan removed).

If the high pressure line has no leak: replace VANOS oil pump.


Connect a high pressure line to a cylinder head, (1) or (3)

Measure the VANOS oil pressure

- If the oil pressure is OK:

Internal leak in the VANOS system of the cylinder head that is not connected

- If the oil pressure is not OK:

Internal leak in the VANOS system of the cylinder head that is connected


Other troubleshooting if a leak was detected on a cylinder head:

- At the cylinder head concerned, remove the VANOS solenoid valves

- Check the O-rings of the VANOS solenoid valves

- If the O-rings are OK: replace the VANOS adjustment unit of the cylinder head concerned

- If the O-rings are not OK: replace the solenoid valves concerned
 

·
Registered
Joined
·
67 Posts
Update, turns out its and M12x1.5 thread for anyone looking at making the own test setup.
 

·
Registered
Joined
·
23 Posts
VANOS pressure Test rig

Update, turns out its and M12x1.5 thread for anyone looking at making the own test setup.
I'm curious how you may have created this test rig. Did you drill and tap something like a brake banjo bolt to NPT pipe thread standards?

Thanks,
Keith
 

·
Registered
Joined
·
21 Posts
I know this is an old thread but one of great importance when it comes to troubleshooting the VANOS. Unfortunately the image you attached Charriot is no longer available but reading your thoughts was extremely insightful!

I too have a pinging sound at idle like EVERYONE else lol but only have 43k miles on my ‘07 e63 and testing revealed the adjusting time (large spread) on the intake solenoid on bank 2 was way above spec at almost 1sec and spec is less than a half sec.

DIS does indicate if the VANOS high pressure test is within spec to replace the solenoid/s, see attached pic.

I sure hope it’s just a solenoid, I’ve seen how much a new VANOS pump costs...
 

Attachments

1 - 12 of 12 Posts
Top