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When you say stuck makes no difference do you mean if it's closed?
go back and watch the video in the first post of this thread.
The concern is that if the solenoid is stuck in the activated position (like in the video), it will be stuck with low oil pressure and a new engine will be in your future. Connected or disconnected is irrelevant if this is the case. Disconnect then verify oil pressure to ensure proper position after disconnection.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by Jacobariel
The solenoid on open lowers the oil pressure and closed raises the oil pressure is what I understand.
Don't think of it as open or closed (because I really don't know which is which). But think of the solenoid being enabled or disabled. Enabled, the solenoid restricts or limits oil pressure to 2 bars. (It also does some other undesirable things.) Disabled, oil pressure is allowed to build normally according to engine speed. There is an upper limit of 4 bars in either case.
Originally Posted by Jacobariel
My thought is then why not just disconnect regardless.
Don't think of it as open or closed (because I really don't know which is which). But think of the solenoid being enabled or disabled. Enabled, the solenoid restricts or limits oil pressure to 2 bars. (It also does some other undesirable things.) Disabled, oil pressure is allowed to build normally according to engine speed.
Bingo! I think the term is "epiphany".
So if disconnecting cuts off all signal/power to the solenoid and solenoid is non functional doing so why does it matter to first make sure it is not stuck on the closed position before disconnecting?
The solenoid is a dummy after disconnecting.
So if disconnecting cuts off all signal/power to the solenoid and solenoid is non functional doing so why does it matter to first make sure it is not stuck on the closed position before disconnecting?
The solenoid is a dummy after disconnecting.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by Jacobariel
So if disconnecting cuts off all signal/power to the solenoid and solenoid is non functional doing so why does it matter to first make sure it is not stuck on the closed position before disconnecting?
The solenoid is a dummy after disconnecting.
It doesn't matter. What matters is that the oil pressure behaves in a normal manner after disconnecting. Watch my video above. Oil pressure is at 30 psi at idle and climbs to 50 psi (in my case) when raising the engine speed. If the solenoid was stuck in the enabled position for some reason, the pressure would not go above 30 psi.
Measuring the oil pressure on your car (assuming you have an M274 engine) requires more tools and effort than on older M276s. See the attached.
go back and watch the video in the first post of this thread.
The concern is that if the solenoid is stuck in the activated position (like in the video), it will be stuck with low oil pressure and a new engine will be in your future. Connected or disconnected is irrelevant if this is the case. Disconnect then verify oil pressure to ensure proper position after disconnection.
Yes, I saw the video. The concern is if stuck activated that means low oil pressure.
But if it stuck deactivated can you still disconnect?
I was told to make sure it is activated first before I disconnect by doing an oil pressure test vs just disconnecting because I'll run the risk of the solenoid being stuck deactivated and if so I would need a new solenoid.
Yes, I saw the video. The concern is if stuck activated that means low oil pressure.
But if it stuck deactivated can you still disconnect?
I was told to make sure it is activated first before I disconnect by doing an oil pressure test vs just disconnecting because I'll run the risk of the solenoid being stuck deactivated and if so I would need a new solenoid.
Stuck deactivated is the goal at the end of this process ….
Yes, I saw the video. The concern is if stuck activated that means low oil pressure.
But if it stuck deactivated can you still disconnect?
I was told to make sure it is activated first before I disconnect by doing an oil pressure test vs just disconnecting because I'll run the risk of the solenoid being stuck deactivated and if so I would need a new solenoid.
Using the terms ‘open’ and ‘closed’ may be where the confusion started.
Let’s talk about ‘activated’ and ‘deactivated’. When the ECU applies 12V to the solenoid it activates. With no power to the solenoid, it is deactivated.
When ‘activated’, the oil pump is in low flow/pressure mode. It is this condition that the solenoid in ‘Tasos’ video is stuck. So in this special condition, the ECU is trying to DEACTIVATE, but the solenoid is mechanically stuck in the ACTIVATED position.
When you unplug the solenoid, the signal from the ECU is deactivated, but the actual position of the solenoid must be checked (via oil pressure) in order to be certain that no damage will occur.
That being said, if the solenoid IS stuck, unplugging it makes it no worse - but engine death is still assured in the near future.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by Jacobariel
Yes, I saw the video. The concern is if stuck activated that means low oil pressure.
But if it stuck deactivated can you still disconnect?
I was told to make sure it is activated first before I disconnect by doing an oil pressure test vs just disconnecting because I'll run the risk of the solenoid being stuck deactivated and if so I would need a new solenoid.
Sorry, but maybe this is not for you. It's important you understand what is happening.
Regardless of whether the solenoid is stuck or not, a disabled state means normal (unrestricted) pressure. An enabledstate means the solenoid restricts the oil pressure.
With the engine running, an enabled solenoid will restrict oil pressure below 3500 rpm. If it became stuck when in an enabled state, it will stay that way. When the engine is off, the solenoid is disabled, but may stay stuck in an enabled state if there is debris that caused it to stick.
I'm not sure who told you to make sure it was activated before disconnecting, but I'm sure it was a miscommunication. And, I'm not sure why you would need a new solenoid because you are forcing deactivation (disabled) by disconnecting it.
I think most people who have disconnected have not measured their oil pressure to determine if the solenoid was stuck. They are by now certain that nothing got stuck, otherwise I'm sure we would have heard about the destroyed engine. I measured mine (video) because I wanted to see what was happening and to make sure I was getting good oil pressure. Because the pressure increased above 2 bars while I was under 3500 rpm, I know my solenoid was not stuck in an enabled state.
Sorry, but maybe this is not for you. It's important you understand what is happening.
Regardless of whether the solenoid is stuck or not, a disabled state means normal (unrestricted) pressure. An enabledstate means the solenoid restricts the oil pressure.
With the engine running, an enabled solenoid will restrict oil pressure below 3500 rpm. If it became stuck when in an enabled state, it will stay that way. When the engine is off, the solenoid is disabled, but may stay stuck in an enabled state if there is debris that caused it to stick.
I'm not sure who told you to make sure it was activated before disconnecting, but I'm sure it was a miscommunication. And, I'm not sure why you would need a new solenoid because you are forcing deactivation (disabled) by disconnecting it.
I think most people who have disconnected have not measured their oil pressure to determine if the solenoid was stuck. They are by now certain that nothing got stuck, otherwise I'm sure we would have heard about the destroyed engine. I measured mine (video) because I wanted to see what was happening and to make sure I was getting good oil pressure. Because the pressure increased above 2 bars while I was under 3500 rpm, I know my solenoid was not stuck in an enabled state.
I would disconnect mine but have no idea were the connector is. I've looked in the hood but not sure.
Why would you not want to stay with Mercedes stock setup ?
The experimental unplug is not warranted and could cause severe engine damage... valve stuck when reconnecting.
Besides MOD-1 does very little until non-stock oil viscosity is used...
Because I am now afraid since in January when I bought the car it displayed the code and now it is not showing.
I figure to be safe of posibble stuck and eventually the code returns and I don't know.
Getting pressure readings was easier than I thought. The port is conveniently located up front on the intake side cylinder head. Best of all, its at the farthest end of the oil pump circuit. NICE!
-Again, ambient temps around 68F / 20C
-Motul 8100 X-CLEAN GEN2 5W-40 (MB: 229.52 / 226.5)
-Oil and coolant temps are now equally matched at 194F / 90C, fully warmed up.
-Piston squirters finally working in sync with variable RPM pressure.
-With piston squirter disabled, oil would reach 185f / 85C at a similar warm idle
@CaliBenzDriver I cannot confirm if cooling jets have internal ball setup to open at certain RPM. My impression is that they are fully open and controlled via secondary piston cooling solenoid (NOW DELETED!)
A more reliable mechanical / spring valve installed. Controlled with higher RPM pressure while maintaining 1.8BAR at idle
Because I am now afraid since in January when I bought the car it displayed the code and now it is not showing.
I figure to be safe of posibble stuck and eventually the code returns and I don't know.
So right now your car is on the fence...
solenoid fault for a while and now no fault.
Getting that fault fixed is seriously labor intensive to open the oil pan for harness + solenoid replacement.
The solenoid fault code is somewhat good + safe.
The dangerous solenoid failure has no code. It blows up the engine to materialize itself. It needs the combination of a valve working in a dirty engine.
To prevent that, some of us have decided to experimentaly keep our solenoid valve disconnected.
So right now your car is on the fence...
solenoid fault for a while and now no fault.
Getting that fault fixed is seriously labor intensive to open the oil pan for harness + solenoid replacement.
The solenoid fault code is somewhat good + safe.
The dangerous solenoid failure has no code. It blows up the engine to materialize itself. It needs the combination of a valve working in a dirty engine.
To prevent that, some of us have decided to experimentaly keep our solenoid valve disconnected.
To get it fixed the shop says it's around $1500. What you said is my concern the dangerous failure has no code. I went from code to no code.
True but if it is no longer showing the code you said why even disconnect and just receive the mod 1 as planned.
Because you only know the electrical state of your system, not the mechanical state. If it were me, I would verify that mechanical state is DEACTIVATED (via oil pressure), then remove solenoid connector to ensure that it remains that way. I would replace the solenoid only if it was verified as being stuck in ACTIVATED position.
It is only for the piece of mind, and the (admittedly very small) possibility of avoiding terminal engine damage.
You had no confusing answers, its just me. Im trying to soak this in. Maybe over thinking.
The solenoid on open lowers the oil pressure and closed raises the oil pressure is what I understand.
My thought is then why not just disconnect regardless.
I see.
As for why the code disappeared, that was precisely what I feared in the other thread, your harness magically working and the solenoid is receiving signals again.
Hence why I recommend disconnecting when you asked after checking oil pressure in case stuff like this happens, hopefully there is no engine damage right now after it re-established communication.
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Hands off the wiper switch 
........................... or un-latch hood, so that wiper is de-activated.
