Intermittent VANOS Code 72 - Inlet late valve

[sapote]

Alright checked wiring again tonight. Everything is good, resistance < 0.5 ohm on all six wires to the DME.

Did find one interesting thing though: I checked each terminal to see how well it was "grabbing" the pins on the solenoid. Pin 1's terminal was pretty loose. I bent the top of it down with a pick to give it a little more "bite" on the pin. We'll see if that improves anything.

I will do this and using the Ampmeter to measure the current to each solenoid and compare, they should be the same: apply 12v directly to each pin at the DME connector (unplugged from DME) and measure the current: p50, p4, p43, p44. Don't power the solenoid more than 30sec to avoid overheating.

[Pklauser]

Alright checked wiring again tonight. Everything is good, resistance < 0.5 ohm on all six wires to the DME.

Did find one interesting thing though: I checked each terminal to see how well it was "grabbing" the pins on the solenoid. Pin 1's terminal was pretty loose. I bent the top of it down with a pick to give it a little more "bite" on the pin. We'll see if that improves anything.

[Pklauser]

Yep, been checked for continuity on all the pins in the connector to the DME and they were all good. I made sure to wiggle the wires while checking as well. I can always check again.

[sapote]

P0010 points to the vanos module having problem of moving the cam to the commanded angle. You have replaced all mechanical parts, so I think the two wires going from DME to the solenoid pack that controls the intake piston. check the wires to pins connection, even add solder to the wire/pin connection.

DME 52pin connector pin4 to solenoid p3;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;p50 to ------------p1.

[Pklauser]

Really wish I was coming back with better news. This remains unsolved. Been to two more track events where this has been pissing in my cheerios. One event it actually didn't crop up at all, another it didn't crop up til the end. I don't trust the car, which really sucks, and I'm starting to run out of ideas.

Let me recap everything that's been done over the last two years chasing this (in loose chronological order):

• Re-soldered original VANOS solenoid pack.
  • This fixed the code 72 that was appearing immediately on startup.
• Replaced VANOS solenoid pack with new OEM unit from FCP.
  • When the code 72 came back, I decided to forego my DIY solenoid repair.
• Validated VANOS solenoid wiring to the DME is good.
• Physically re-timed engine and made sure it was spot-on.
  • Did not remove VANOS unit to torque hub bolts.
  • Also did not double check cam bolts underneath hubs. I know the PO upgraded them to the new torx-bolts, but that's all I know.
• Replaced intake cam sensor with VNE unit.
• Replaced VANOS pump unit with new OEM unit upgraded by and purchased from Beisan.
  • This fixed a legitimate and confirmed oil pressure issue.
• Replaced intake cam sensor with BMW unit.
  • Learned that this is identical to the BMW unit, good use of funds, but here I am.
• Validated that the intake cam sensor wiring to the DME is good, <0.5 ohm resistance.

Continuing On

I reached out to Lama from Beisan systems, RIP Raj, to see what she thinks. She's had me go through some troubleshooting, but nothing that wasn't already tried in this thread: cleaning connectors, running the car at various RPMs for various intervals and seeing when the codes reappeared. Interestingly she operates completely with generic OBD codes, I'd think the BMW-specific codes would give more info, but I suppose not everyone calling in has that information. My OBD code is P0010. She suspected the VNE intake cam sensor to be bad, since it's not Genuine BMW, so I bought a Genuine BMW one, only to find that it's identical to the VNE part. The VNE part just has the BMW letters ground off. It sounds like she'll want to send me a Beisan solenoid pack next. We'll see how it shakes out, since the current solenoid pack only has maybe 5k miles on it.

Just got TestO downloaded, haven't hooked it up to the car yet, but it looks like it may be able to provide some insights into expected/actual cam angles, which I haven't been able to view with any other tools thus far. Will play around and report back on that.

Grasping at Straws

Is it possible this code is a big fat red herring? Everything has been pointing to the intake cam, so that's where all of my focus has been. Is it possible that exhaust cam sensor issues could throw the code 72 for some wild reason? I ask because I drove around with the solenoid completely unplugged, and all the INPA codes I got were related to the inlet cam, so it's almost like it just didn't care about the exhaust cam.

[karter16]

The bottom of the sreenshot shows hex B8, and other error codes that I have not tried to understand why it listed the long list....

That's just the hex representation of the data presented above. 0xB8 in decimal is 184 - the error number, 0x91 is the error type (istwert zu gross = sensor value too high), 0x24 and 0x28 are Error Frequency and Logistics Counter respectively and the remaining bytes are the 5x values recorded for each of instances 1 to 3. first 4 values are bytes and the 5th is a word.

[Pklauser]

Pull out connector at the DME and have a look, and check the resistance from DME pins to the IN sensor connector pins.

Will do.

Did some more testing today while I was at the track. 72 & 184 seem to consistently come back when I'm pushing it, then they started popping up on the street on the drive home as well, including at lower RPM. I cleaned out the solenoid connector in case that was somehow causing an issue. I'm starting to wonder if the solenoid has given up so soon. Going to talk to Lama at Beisan and see what they think/see if I can get another solenoid to test with or something.

nextelbuddy I see you had a thread here recently, did you ever get your 72/184 issue sorted out?

[sapote]

The errors happened at higher rpm. The bottom of the sreenshot shows hex B8, and other error codes that I have not tried to understand why it listed the long list....

Error at higher rpm could be related to electrical signal on the IN cam sensor. Pull out connector at the DME and have a look, and check the resistance from DME pins to the IN sensor connector pins.

[Pklauser]

Whelp, 72 and 184 have reappeared at VIR this weekend. Frustrating.

72 - "Intake VANOS, late valve" again comes with: "Line break, no value. Missing." Though this time it also came with: "Error currently exists". So maybe it's more firmly dead?
184 - "Intake VANOS, regulation" comes with: "Actual value too large".

I don't know where to go next. The VANOS oil pressure was clearly incorrect, but apparently not the root cause.
Looking at the camshaft angles in INPA, they move around and read just fine. I have no idea what they should be to know if they look right.

I can check the physical timing again, and actually pull the VANOS unit off this time to verify I get the cam retarded all the way, but I really think I had it right last time. I will also check the wiring from the intake cam sensor to the ECU, since that isn't something I checked. If anyone has any good ideas here, please share.

Definitely seems odd that it's only present on the intake side.

[Pklauser]

New Beisan unit in, and now I'm seeing ~110 bar running through the VANOS test. We'll see if this resolves the codes, but definitely a step in the right direction here.

New Unit:

https://youtu.be/00WluGbn87A

Old Unit:

https://youtu.be/xsGHc2ilpt8

[sapote]

Edit - Adding that I have a Beisan re-drilled OE disk that was installed by the PO. Motor is a bit of a frankenstein, but the VANOS unit presumably has 170k on it.

Either the pump is inefficient (pistons not matched to disk holes) or vanos has too much internal leak (pistons seals, P regulator, etc)

[maupineda]

FWIW, the unit I got seemed brand new, and came in what seemed manufacturer’s packaging. The bolts all were torx as BMW had updated all those fasteners towards the end of the life of the S54’s everything in the unit seemed new. I chose not to send the core unit back so my price was close to 2K for the whole unit.

The new units for sure are legit, and 2k ain’t exactly cheap, but surely there is margin in there. It can possibly be they have a line of business with the VANOS supplier and the cores are needed for remanufacture purposes. Who knows. But the new units cure my pressure issue. I measured it at 110 bar.

[Pklauser]

I had spent so much I just wanted zero risk, like what if they disassembled the unit and mixed with another one’s disc, things like that made me ask for an unmolested unit. And yes, I chose the VAC hub route.

Yea I get that.

It's kind of weird to me that they take VANOS cores back, but they don't sell refurbished VANOS units. Surely they're not paying us $500 just to harvest the pump disc they sell for $150, or the solenoid they sell for $200. The math ain't mathing. Call me superstitious, but it does kind of rub me the wrong way.

They're super responsive, but when I asked about their warranty they said they've never had a customer's product replaced. I think the failures and discontinuation of their own in-house pump disc disproves that statement.

Hate that I have to get into non-OE solutions no matter which way I proceed here. Feels like risk in the pump disc world, feels like risk in the hub world.

[maupineda]

Awesome, I'd seen your posts in the other VANOS threads and it seemed like we had similar diagnoses, really appreciate you chiming in here.

I can ask Beisan as well, but will they not redrill the disk that's original to the unit and keep them as a pair? How did you mitigate the exhaust hub tab shearing issue without a redrilled disc, VAC hub?

I had spent so much I just wanted zero risk, like what if they disassembled the unit and mixed with another one’s disc, things like that made me ask for an unmolested unit. And yes, I chose the VAC hub route.

[Pklauser]

I had hesitation issues when I had low pressure, also it will always pass VANOS tests, but the time to adjust was high (close to 300ms)

you want at least 100bar with oil at operating temp (75 to 90).

If the pressure is low the adjustment will be erratic if the engine needs to adjust cams continuously, as it would be during city driving or roads with varying load conditions.

the issue with redrilled discs is that you are shooting in the dark as those could be worn and drive lower pressure

beisan sells new units for not that much (1500). I actually asked them for a unit which disk was not removed and original to the unit, this meant no redrill.

edit: like you my pressure wan in the 40’s bar too.

Awesome, I'd seen your posts in the other VANOS threads and it seemed like we had similar diagnoses, really appreciate you chiming in here.

I can ask Beisan as well, but will they not redrill the disk that's original to the unit and keep them as a pair? How did you mitigate the exhaust hub tab shearing issue without a redrilled disc, VAC hub?


Edit - Reading from Beisan here it actually sounds like they might keep the disc and unit as a pair?

"NEW oil pump disk upgraded with precise CNC machined smaller holes to prevent exhaust tab breaking, as Beisan-Systems BS025, but with the brand new disk."