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2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by BDC90
So My question is still. Will the oil pressure solenoid leak oil if it's unplugged/ deactivated?
Do you mean leak from where you detached it or cause the cam position sensors to "leak" oil more? I would say that if it is the first, I don't know AND I don't know why it would. It is inanimate at that point. Plus, if there was oil exfiltration for some reason, I don't think it would have anything to do with whether the solenoid was active or not. I plan to use one of these to "cap" it off, anyway.
One thing to note from the other thread that was posted on the first page is the difference in hot idle pressure. 27 psi with the valve connected and 17 psi with the valve disabled.
I'm aware oil pressure needs at hot idle under no load are very minimal but I wonder if there is another system requirement that depends on a set minimum pressure and needs the valve to maintain a higher idle pressure.
Btw I disconnected the valve before leaving work this afternoon. After reading some of the posts here I was skeptical if some of the perceived improvements were just placebo, but to my surprise the MCT is definitely smoother in stop and go and on and off throttle. It's hard to explain but it seems the rev matching from 2-1 coming to an almost stop and then back on throttle is much more predictable and smooth. I really didn't think I would notice anything so quite surprised by that.
You're getting 10psi less with oil valve unplugged - - seems backwards ???
Perhaps this is something new ?
He has a video towards the top showing hot oil pressure with valve plugged in at 27 psi
After a few more posts he wires up a set of bulbs to show when ECU is requesting valve actuation but has it unplugged and it shows hot oil pressure at 17-18 psi.
Actually I just realized that at the start of the "hot" valve plugged in video the coolant temp was only at 72c. Towards the end of the video where it is at 95+ it settles to 18psi just like with the valve unplugged. My mistake.
Screenshot below
Looking forward to going on another drive tomorrow to determine if the MCT was just having a good day or if there really is a noticeable change in ECU logic pertaining to clutch engagement and rev matching.
The 2->1 bucking with off/on throttle was the one thing that made me nearly regret this purchase in 2014.... fortunately my foot learned to modulate the throttle in these situations like a manual transmission driver modulates the clutch for smoother engagement
don't expect stellar matched shifts from the tranny right away.
First the ECU has to readapt the engine then tranny tries to catch up with shift points - It's a bit disorganized the first 300 city Miles (frequent shifts unlike Hwy). It's fairly stable by 1000.Mi
Once the engine performs predictably the tranny matches that very well, but that comes as a trailing second.
Before everything below 1500.RPM had poor throttle control including at Hwy speed. Now it's slick
I think the normalized crankcase pressure helps MAP sensor a lot at low throttle openings - This is in addition to working Intake VVT's helping that.
When you drive under improved conditions you realize the ECU is able to manage performance with more precision. The engine responds better right from 900.RPM.
Be patient while more improvements are slowly rolling back with more even compressions. The ECU is remapping extra power.
+++ Hint of latency at pick-up :
We have seen how everything below 1500 RPM was like. I wonder if engine will keep improving to deliver perfect pickups from stop.
-- I do feel like ECU may be introducing latency before pickup from stop even on non-MCT.
-- Even on TC rolling the car frees up that delay.... is this a handshake with ESP "Hill-assist: free" ..?
-- Pedal sensor itself is perfect, just not from 0... a far cry from what we got used to.
Last edited by CaliBenzDriver; 11-25-2023 at 12:48 PM.
I wonder how that gentleman got oil pressure on the banks gauge. I have one of them and it does not display any oil pressure of any sort. Wonder if I need a external sensor to get this to display.
I wonder how that gentleman got oil pressure on the banks gauge. I have one of them and it does not display any oil pressure of any sort. Wonder if I need a external sensor to get this to display.
Yes, indeed you do.
Oil pressure is the empowering data.
Sensor plug is near the base of oil filter.
The ECU has NO oil pressure sensor.
Bosch switches pump Hi/Lo pressure based on RPM, TEMP and calculated LOAD... to save fuel with more friction.
Last edited by CaliBenzDriver; 11-25-2023 at 03:36 AM.
Any reason I can't take an sacrificial harness, cut the wires and use the ends as plugs for the pressure sensor and the harness?
There isn't oil pressure on the wiring side of the harness. That harness would do nothing to stop actual pressure. It would be the slightest seepage. Unplugging is the way to go there.
Drove 2 hours on Thanksgiving in the E63. I can report that highway driving now reminds me more of my E55 when I first test drove it. Just the slightest throttle required to keep the car moving at 70-80. I continue to be pleased.
Do you mean leak from where you detached it or cause the cam position sensors to "leak" oil more? I would say that if it is the first, I don't know AND I don't know why it would. It is inanimate at that point. Plus, if there was oil exfiltration for some reason, I don't think it would have anything to do with whether the solenoid was active or not. I plan to use one of these to "cap" it off, anyway.
when I pulled the plug out of the socket at the front of the engine , there is oil on the plug. Just like a bad CPS plug.
There isn't oil pressure on the wiring side of the harness. That harness would do nothing to stop actual pressure. It would be the slightest seepage. Unplugging is the way to go there.
That's why I was surprized to find oil on the removed plug.
So if there isn't supposed to be oil pressure on the plug side of the oil pressure solenoid, could that oil have seeped there from a branch of the wiring harness that is connected to the CPS plugs? It's gotta be one of the lowest points in the harness and I did have 1 leaking CPS replaced when I bought the car.
It seeped through the solenoid just like it seepa through the cam position sensors and cam adjuster magnets.
Yeah so it will continue to leak when unplugged. Hmmm have to figure out something there, being on the front of the engine that could get a little messy. It doesn't look like a sacrificial harness plug with seal it up.
Yeah so it will continue to leak when unplugged. Hmmm have to figure out something there, being on the front of the engine that could get a little messy. It doesn't look like a sacrificial harness plug with seal it up.
It was leaking into the plug before. Now will have one drop per year onto the ground. Does that really bother you?
Done. I sacrificed a sacrificial harness by cutting the wires and using the plugs to keep the existing plugs clean . I have an aftermarket warranty so if an issue pops up I can plug it back in quick.
Oh LOL , I thought it would seep way more than that. Hehe. OK unplugged it is.
What mileage on your engine for reference ??
Yeah couple more drops or perhaps less as the crankcase pressure normalize itself to acceptable levels.
High blow-by engine:
-- I would take this as a wake up call to check all engine electrical plugs for oil leaking into harness.
-- Castle on the hill to be protected is the ECU. Get it cloned while it's alive. Replace collection of leakers, replace harness or use matching pigtails.
-- Consider getting a relative compression test to evaluate non-contributing cylinder. Hopefully all cylinders are even-steven instead of a single bad.
-- then progress to andoscopic inspection for vertical scoring from broken cylinder rings.
-- or let someone else enjoy all of this fun!
What i'm saying is the writing is on the wall... go easy with the ol'girl
🤞
Last edited by CaliBenzDriver; 11-26-2023 at 12:11 AM.
57k on car and motor. Bone stock. I went through all the usual stuff. New CPS's. Harnesses on magnets. Index plugs, Trans and differential fluids. Just a hint of oil in ECU but non now. I'm doing 5w-40 every 5k. The service history showed regular oil changes.
Done. I sacrificed a sacrificial harness by cutting the wires and using the plugs to keep the existing plugs clean .
I have an aftermarket warranty so if an issue pops up I can plug it back in quick.
Don't mod, take it to the doctors now.
Your last repair bill must fall within contract or nobody will deal with warranty job...
I bet they are going to say "everything normal, "they all do that!" and they sure do.
✌️
Last edited by CaliBenzDriver; 11-25-2023 at 01:42 PM.
11-25-2023 | 01:30 AM
