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The said DTC P2088 if using Xentry is explained as follows :
The problem is : FAULT OCCURENCE with value under 2.5V need better explanation, at what RPM is this and using scope or ordinary DMM voltage reading ?
This test will help you from chasing the wrong rabbit hole.
Test method.
Note : I am using LEFT BANK intake and not RIGHT bank intake, because my turbocharged engine has aftercooler coolant bottle blocking access if I use RIGHT bank intake.
It is the same operating parameter for LEFT or RIGHT intake magnet. So no worry.
A device is used only for DC Voltage reading
B device is only for Duty Cyle and Frequency. This is the PMW signal specification send out by ECM to magnet. Thus knowing frequency could help to compare between A vs B more accurately.
Here we are looking for known good reading.
What I can not verify 100% is, if car on the road with gear engaged , will the magnet electrical values based on RPM will be the same or not ?
I believe it will be the same because we can do VVT degree commanded vs actual degree achieved while stationary or while on the road in gear, with the same result.
This is how the magnet duty is.
The magnet is like a pusher pin. When power applied, based on X duty cycle it will move a few millimeters pushing the mechanical oil valve inside the VVT sprocket.
It will push this oil valve :
That oil valve will then open up to allow oil into VVT sprocket oil vane and do its retard/avance magic. As simple as that.
My test wire is DIY, using original MB connectors.
I have made quite a few wire test kit for my engine, because wire kit is most reliable connection compared to probing with the small probe needle pin.
.
The test in video, camera sync to tablet screen showing the electrical data , accurate to 1/25th second. That is why you hear me saying SYNCRO-SYNCRO when doing more than 1 video source.
NOTE :
If somehow your ECM which is the driver or power provider for the magnet has a bad driver, you will need a scope to see the PWM signal being distorted or not. DMM can not see such signal information.
.
Channel D in brown is how a PMW signal looks like in an electrically noisy engine running enviroment. This is a good signal.
I forgot to add.
PMW signal will never be read its full system voltage ( voltage sent by ECM ) if using DMM. You need a scope to see the actual voltage.
Example, no matter how low the duty cycle is, the scope will see 13.9V system ( mine ) voltage when engine is running. DMM is shown to show 0.3 volts only when at 6% ish duty cycle.
Very informative post,
Here’s the quick and dirty tool(hack) used in the field to visualize plunger movement. Quick and dirty, but effective.
The magnetic solenoid sometimes can weaken over time. Adding voltage to them while feeling the force applied by the plunger is a common test. Put the old faulty one next to a new one and you’ll feel the difference…
The MAXIMUM amount of pressure the magnetic solenoid plunger is capable of applying to the oil control valve is 20-22psi.
This type of always on PWM circuit, is about heat and energy/efficiency control vs force.
The last pic, is a different kind of PWM VVT solenoid that is designed for high pressure oil flow control, unlike the magnetic solenoid the German Engineers use in a variety of engines. ( not just MB). Those PWM solenoids are capable of higher force/load vs the magnetic solution.
This will be revisited in our PM.
And is very important when we talk about oil flow control through the VVT adjusters and just how that is managed.
Here’s some basic design/testing articles related to (industrial) magnetic solenoids:
IGNITION ON, Engine OFF.
Blo-ody hell, I thought the 4.55 millivolts to the magnet is "noise" or DMM drifting. It is Not !!!!!
It is the diagnostic signal or bias voltage, or whatever the name is, for ECM to know magnet is there.
I would have thought something higher like 50-500 millivolts would be likely.
This is quite insane at 4.5 miilivolts loaded. What if so many wires bundled up together producing induced voltage or ghost voltage to the next cable
I say loaded because the magnet does consume super crazy low 0.5 milliamps too.
Example., Bank 2 INTAKE magnet - Red UNI-T is reading micro amps, thus 547 uA is 0.5 milliamp EXHAUST magnet - Blue Hioki is reading milliamps, 0.4 milliamp
-----------------------
Below is the table of further test.
This test result is unique for both Bank 1 and 2 INTAKE magnets at 1.4V to 1.5V loaded, because of impedance involved from the DMM in in-line current mode and DMM in voltage mode.
I am not an electrical/electonic engineer, but I have seen reading gets effected by using a few DMM on the same circuit, but I never actually work at this very low voltage and crazy low current.
An ideal voltmeter has an infinite input resistance so that the instrument does not draw any current from the test circuit. However, in reality, there is always some resistance that affects measurement accuracy. To minimize this problem, a DMM’s voltage measurement subsystems are often designed to have impedances in the 1s to 10s of MΩ. If you are measuring low voltages, even this resistance can be enough to add unacceptable inaccuracies to your measurement. For this reason, lower voltage ranges often have a higher impedance option such as 10 GΩ.
With some DMMs, you can select the input resistance. For most applications, it can be said the higher the impedance, the more accurate the measurement. However, there are a few cases where you might choose the lower impedance. For instance, a conduit that has many different wires inside might have coupling across the wires. Even though the wires are open and floating, the DMM still reads a voltage. The higher impedance isn’t sufficient to eliminate these ghost voltages, but a low impedance provides a path for this built-up charge and allows the DMM to correctly measure 0 V. An example of this at a lower voltage range is if you had traces close together on a circuit.
===========
---------------
When u guys test the magnet with direct current and not PWM, please do it less than 2 seconds because magnet coil may burn.
It is designed to be PMW powered and not direct powered aka full power.
.
If direct current at 13.9V to solenoid, it is approx 1.7 amps and the sound of the piston impact is loud...
That is all the update for today...........
Damn, this test given me excuse to get newer DMM to replace my darkened screen Fluke 289 of 15+ years which is high digit count , very accurate and can do A LOT, but no bluetooth.
I hope the LCD specialist I am about to contact on MOnday can replace the polarizer film on this and get it back to normal again. They can do for cars LCD screen.
Its not the fastest refresh rate DMM for today's standard.
What exactly are you trying to test? And more importantly how are you powering them?
If you check your PM’s when I have the time to finish writing them, later tonight or tomorrow morning.
I can upload a video of my testing these at operational voltage for 20 minutes (or more). They can get warm, as I mentioned when I tested them, if you overdrive them. To have them blow means you may have done something excessive.
My tests are after MAXIMUM force solenoid is capable of producing.
Anyways, this is going to turn into another mega thread soon, as much of this is already rehashed.
Good Luck
Last edited by crconsulting; Nov 2, 2025 at 11:52 AM.
I forgot to add.
PMW signal will never be read its full system voltage ( voltage sent by ECM ) if using DMM. You need a scope to see the actual voltage.
Example, no matter how low the duty cycle is, the scope will see 13.9V system ( mine ) voltage when engine is running. DMM is shown to show 0.3 volts only when at 6% ish duty cycle.
You're showing the coil variable duty-cycle used by ECU to position camshafts by positioning oil control valve to route pressure Fwd/Rwd chambers.
The pulse is controlled from 10 to 90% duty, right? narrow pulses
I don't believe a DC current measure is significant in this AC circuit.
DC Amp setting shows tiny number in AC circuit
The use of electric pulses make this circuit a power efficient hydraulic control.
> INPUT VS. OUTPUT...
Use the duty cycle to plot actual VVT postion as seen by CPS on a hot running engine with matching Rpm (not idle pressure) else numbers remotely significant.
It won't be exactly 100% acurate measurements but still useful trends.
> MEASURING ERROR...
You can study how external variables derate the position acuracy vs. your set baseline.
We know accuracy likely skewed by ...:
Engine Rpm : 650 / 1200 /2000 /2500
DC chassis voltage: 12.6 /14.9V
Oil temp: cold /hot engine
(Oil viscosity)
Min + Max values likely static at both extremes but linear section in-between significantly distinct enough to corrupt the throttle logic .
The oil valves have no return spring...
Rpm oil pressure is used to exert small positive pressure on the valve against plunger. That's why live conditions are more meaningful than static numbers.
rarity downtown Tokyo, JP.
Last edited by CaliBenzDriver; Nov 3, 2025 at 01:23 AM.
My favorite, google search, pulls up tons of diagnostic procedures of direct 12v hook up for testing of PWM magnetic solenoids on engines (and industry) . Do you really think mechanics in the field are using PWM drivers to test these? LOL
As I mentioned in my PM, I used a variety of methods to drive these including PWM signal generator in search of maximum force magnetic solenoid was capable of providing.
Diagnosing a malfunctioning camshaft adjuster magnet is generally straightforward due to its location at the front of the engine. For M272 engines, while access may be slightly more complex, it is still manageable. A simple test involves applying 12 volts of electrical current to the magnet contacts; a functional magnet will produce a clicking sound. If one magnet clicks while the other does not, a replacement is needed.
No need to turn this into another confusing mega thread. This is pretty basic troubleshooting. But I guess this thread is about overcomplicating an easy test performed by PROFESSIONAL techs daily.
Good Luck.
Last edited by crconsulting; Nov 3, 2025 at 03:55 PM.
You're showing the coil variable duty-cycle used by ECU to position camshafts by positioning oil control valve to route pressure Fwd/Rwd chambers.
The pulse is controlled from 10 to 90% duty, right? narrow pulses
I don't believe a DC current measure is significant in this AC circuit.
DC Amp setting shows tiny number in AC circuit
The use of electric pulses make this circuit a power efficient hydraulic control.
> INPUT VS. OUTPUT...
Use the duty cycle to plot actual VVT postion as seen by CPS on a hot running engine with matching Rpm (not idle pressure) else numbers remotely significant.
It won't be exactly 100% acurate measurements but still useful trends.
> MEASURING ERROR...
You can study how external variables derate the position acuracy vs. your set baseline.
We know accuracy likely skewed by ...:
Engine Rpm : 650 / 1200 /2000 /2500
DC chassis voltage: 12.6 /14.9V
Oil temp: cold /hot engine
(Oil viscosity)
Min + Max values likely static at both extremes but linear section in-between significantly distinct enough to corrupt the throttle logic .
The oil valves have no return spring...
Rpm oil pressure is used to exert small positive pressure on the valve against plunger. That's why live conditions are more meaningful than static numbers.
rarity downtown Tokyo, JP.
Cali, the scope capture in with engine running and that small PWM pulse is at idle, which is 6.6% duty cycle.
The 0.5 milliamps on the DMM, that is engine not running , only ignition ON and no duty cycle.
Have fun in Japan my man....
My favorite, google search, pulls up tons of diagnostic procedures of direct 12v hook up for testing of PWM magnetic solenoids on engines (and industry) . Do you really think mechanics in the field are using PWM drivers to test these? LOL
As I mentioned in my PM, I used a variety of methods to drive these including PWM signal generator in search of maximum force magnetic solenoid was capable of providing.
No need to turn this into another confusing mega thread. This is pretty basic troubleshooting.
Good Luck.
Holy cow, what is wrong with you ?
This thread is to help member Alpina. It is stated in the 1st post with video.
That youtube link is UNLISTED, its for members here only.
How you want to test your magnet is up to you and you have lots of parts to play with, most members do not have parts to play with because they are not professional tech like you.
I still stand firm that I will only test my magnet to the duty cycle I captured, which was highest 40% during the 1st post video.
Why would I test it to 100% long term when the application on the car itself is not showing full direct system voltage ( full power ) by ECM ?
Sure, I tested full power for 2 seconds, but that is all I will do because I want to be able to re-use this magnet in emergency.
MB or any modern cars Professional Tech must own PWM driver, it is too cheap to not get one. Mine is under US$40 only. I got a few PMW drivers, but this Hwaut P200 is the easiest to use.
So many components on our car is PWM powered....how to test the component characteristic as per ECM command if we cant replicate the
PWM pulses ?
Must have picoscope too. You know MB official scope is Pico 4 channel automotive version....right , it even has MB logo on it.
-----------
On the subject of our PM, that we still need to communicate... you are VERY good and senior tech, must learn from you
As I said in my PM, it’s not clear what you’re trying to convey here. Firstly I’m on (was on ) a phone which is tough in general.
There are multiple threads going with the poster Alpina. That’s probably not helping either.
Originally Posted by S-Prihadi
Holy cow, what is wrong with you ?
Apparently nothing, since I know how these are actually tested daily all over the world. Probably because I actually worked in the field.
Wanted to make sure we are clear on how these are tested in the field. As things get lost in the obfuscation of over complicating a simple field test used every day. It’s a test, you’re not driving to the grocery store like this for gods sake….
Originally Posted by S-Prihadi
MB or any modern cars Professional Tech must own PWM driver, it is too cheap to not get one. Mine is under US$40 only. I got a few PMW drivers, but this Hwaut P200 is the easiest to use.
So many components on our car is PWM powered....how to test the component characteristic as per ECM command if we cant replicate the
PWM pulses ?
While you would think that, and I agree with you, the reality is most independent techs in the field won’t have this. And test these magnetic solenoids without damaging anything. (MB factory techs of course have this supplied in house to test other electronic components too)
But few independent techs will have invested the $6k required for the MB pico scope kit. https://www.mbusassep.com/equipment/product/19135
Why would you think a DIYer would have this scope kit? Why overcomplicate a simple test they can run themselves with the simplest of equipment? He ( (Alpinaturbo) doesn’t even have XENTRY yet?
On a different note, @CaliBenzDriver
If you get a chance the Honda Museum is a must stop if you have the opportunity.
The Japanese are fiercely loyal consumers, they have their share of exotics, and foreign cars but for the most part everyone drives Japanese.
Couple of foreign cars sightings in Tokyo, from my last trip a few months ago.
The E type Jaguar had come out of Naito Auto
Not to mention the models not for export
Last edited by crconsulting; Nov 3, 2025 at 04:48 PM.
Holy cow, what is wrong with you ?
This thread is to help member Alpina. It is stated in the 1st post with video.
That youtube link is UNLISTED, its for members here only.
How you want to test your magnet is up to you and you have lots of parts to play with, most members do not have parts to play with because they are not professional tech like you.
I still stand firm that I will only test my magnet to the duty cycle I captured, which was highest 40% during the 1st post video.
Why would I test it to 100% long term when the application on the car itself is not showing full direct system voltage ( full power ) by ECM ?
Sure, I tested full power for 2 seconds, but that is all I will do because I want to be able to re-use this magnet in emergency.
MB or any modern cars Professional Tech must own PWM driver, it is too cheap to not get one. Mine is under US$40 only. I got a few PMW drivers, but this Hwaut P200 is the easiest to use.
So many components on our car is PWM powered....how to test the component characteristic as per ECM command if we cant replicate the
PWM pulses ?
Must have picoscope too. You know MB official scope is Pico 4 channel automotive version....right , it even has MB logo on it.
-----------
On the subject of our PM, that we still need to communicate... you are VERY good and senior tech, must learn from you
I 100% second your reserve about NOT following professional advice to do monkey business with good AC solenoid coils.
WHO in his right mind powers up an AC coil to unlimited DC current and watch it blow up ?
I dont understand WHY a trained expert keep lecturing us on topics he demonstrates having remote ability to grasp ? (the "AC solenoids", the "ON/OFF Phasers", ....) - Consistently backwards advice from a trained professional... it's suspiciously hard to trust.
So many ppl drastically modify their Benz more than a few experimental plugs. What is wrong when curious ppl experiment making their powertrain run better + burning less oil ??
Most owners happily run stock: MOD-0 has top value.
Smart folks have realized that... :
VVT Phasers are NOT positioned ON/OFF nor by DC voltage: OUCH!
Nearly everybody understand why this detail is essential for results.
Camshafts are positioned where the ECU needs them to match with map-stored fuel.
Mismatched mixtures earn a map-stored LEAN penalty = slow poke!
Thank God For Intelligent Honest Ppl that are able to learn as they go. They enjoy better karma.
MBW readers recalls friends recently purchasing dead VVT Solenoids new from FCP Euro trusted supply chain... likely fried by DC Voltage testing then returned - Begin by using your favorite Ohmmeter to test coils.
BTW for the same price... No one should overload an ECU by testing two solenoids on one channel: OUCH!
Beginners 101 don't make rookie mistake because they know better than overloading circuits.
Last edited by CaliBenzDriver; Nov 3, 2025 at 10:43 AM.
WHO in his right mind powers up an AC coil to unlimited DC current and watch it blow up ? It's expensive to fool around good parts.
Oh boy, welp, that’s the end of this thread. Another time suck leading to endless confusion with AI posts and the usual misinformation.
I figured it would come down to insults with you because that’s pretty much what people resort to when they can’t post substance. You’ll notice the tone of your post vs mine.
Anyways, the answer:
Nobody.
Enjoy your echo chamber, just refrain from posting more nonsense and you won’t look foolish. It’s pretty hilarious at this point.
We can tell you repair phones and PC’s, NOT CARS.
Good Luck in your quest to re-engineer large manufacturers proven designs, who have endless resources, with your “discoveries”, generated from a dark basement with a handful of sockets and pictures of your dash.
Diagnosing a malfunctioning camshaft adjuster magnet is generally straightforward due to its location at the front of the engine. For M272 engines, while access may be slightly more complex, it is still manageable. A simple test involves applying 12 volts of electrical current to the magnet contacts; a functional magnet will produce a clicking sound. If one magnet clicks while the other does not, a replacement is needed.
Last edited by crconsulting; Nov 3, 2025 at 03:54 PM.
Oh boy, welp, that’s the end of this thread. Another time suck leading to endless confusion with AI posts.
I figured it would come down to insults with you because that’s pretty much what people resort to when they can’t post substance. You’ll notice the tone of your post vs mine.
Anyways, the answer:
Nobody.
Enjoy your echo chamber, just refrain from posting more nonsense and you won’t look foolish. It’s pretty hilarious at this point.
We can tell you repair phones and PC’s, NOT CARS.
Good Luck in your quest to re-engineer large manufacturers proven designs, who have endless resources, with your “discoveries”, generated from a dark basement with a handful of sockets and pictures of your dash.
my friend, you have a condescending view on all the things you ignore.
It is computers and signal wires that power the finely crafted engine parts you're familiar with.
It's not rocket science...
what's so difficult for you to learn?
Help us with true advice that complement WIS, not contradict reality ("ON/OFF positioning", "DC coils", ...)
I wasn't gonna volunteer my opinions to set your record straight but Surya picked up exactly on your advice to "Power AC coils on DC"... Unbelievable.
Insultes where ?
What is YOUR continuous hate supposed to mean: "with your “discoveries”, generated from a dark basement with a handful of sockets and pictures of your dash."
- All your premium training and experience should help accomplish something worthwhile we can like.
All honest contributors are very welcomed. Just honest pragmatism, not drama-mama insults. Please help us HONESTLY.
Well see what materialize: actions speaks louder than words.
we agreed to help sell more defective parts
we agreed not to deal with professional racing
we agreed "stock is ok"
That's very fair accommodations, right?
We're experimenting smoother timings with good oil.
Why don't YOU pick a useful topic to honestly contribute YOUR real expertise. Show us YOUR mojo: bore-score possibly ?
I do not insulte anyone to feel better, I use my tools...
Last edited by CaliBenzDriver; Nov 3, 2025 at 10:54 AM.
Both of you can argue all you like ......
I does not do any good to members here...........
Time out please
Here's what I really see out of my not so dark basement window... Mount Fuji JP - this morning scene
Mt Fujisan local HONDA specialist 👍
actually real Japanese FUJI apple at Fujisan
These original apple type is bigger and unbelievably much sweeter than American Fuji apples... day & night!
Lot's of genuine intelligent ppl around here.
Last edited by CaliBenzDriver; Nov 4, 2025 at 06:24 AM.
Back to topic......... ( image upload seems to be delayed today, 5 minutes approx between I PRESS SUBMIT and the post having the said images )
When car is not in gear, the VVT timing algo is different compared to when car is on the road. Logically, as the engine load is different.
As far as VVT degree change, based on my archive for road test in 2023....it is below :
Stationary test Only INTAKE LEFT BANK magnet is logged for its milliamps, frequency and duty cycle
Intake VVT will do only 33 to 5 degrees, not all the way to -5 degree
Exhaust VVT will do from its -23 degrees all the way +2 degrees , which is 9 degrees more than when on the road test of 2023.
All video capture showing electrical data from 2 different tablet and laptop video capture, is accurate at least to 0.08 second.
However electrical response of the DMM is probably1 time per second update as it was on Auto ranging mode and via blueetooth to tablets...Dugggh.
The highest power consumption when engine already decently warm at 60C or so coolant temp is approx 510 milliamps at close to 40% duty cycle.
When engine is still cold/cool, magnet power consumption highest can be 550 milliamps, while at 38.7% duty cycle.
The frequency applied to the PMW is higher when engine is cold, can be approx 500hz and when engine is warm enough usually 200hz.
I would say no more than 600 milliamps for the INTAKE camshaft magnet is what I will be seeing in 30C ambient temperature I am in.
For colder country, I don't know.
============
To know better the overall electrical characteristic of the way ECM pulsed this magnet, EXHAUST camshaft will need to be logged too.
I know/read from Schaeffler presentation on VVT , the camshaft own spinning torque itself does effect how VVT perform, that meants also the magnet amount of work = milliamps = watts
Attached the document, a 2014 edition. The document title has Kolloquium .
A "Kolloquium" is the German spelling for colloquium, which refers to an academic meeting or seminar for discussion, often featuring a presentation and a question-and-answer session
We know the camshaft seen from front of engine is CW rotation.
Advance or Retard is CW and CCW rotation. I suspect CCW rotation of the VVT would need more power for the magnet ... maybe.
Thank you for your clear study of the therory and practice of the VVT phaser positioning.
The reality you're showing with Xentry clearly closes the loop with WIS theoretical presentation.
It's hard to miscontrue clear reality - Enough said.
From there it's interesting to understand HOW camshafts get positioned where they are.
The ECU manages the distinct target position of the 4x camshafts. This is not done by pulse values carved in stone.
Camshafts reluctors do not directly read individual positions. It's computed from the relative tic-marks of [CKP + CPS] (true but unnecessary).
ECU does not blindly apply a fixed pulse-width to electro-magnets. ECU learns what pulse values are necessary to reach individual targets. These values are stored in a lookup table, so called mapped data.
This is done to SLOWLY self-adapt the engine against ALL current operating variables.
Is that all very clear ??
The next step is also clear: when any of the variable factors change, the result is an increase of positions error rate.
The intake/exhaust positional errors significantly affect the engine timings.
Stabilizing variable factors minimizes variations to reclaim GDI performance.
What proves these understandings is the experimental practice to reduce errors.
The conclusion is the cam positioning require stability not available with stock.
ECM variable pulse the magnet slowly........ when needed, like minor degree change.
I am too lazy to upload the video, it is near 10 minutes long.
I use the video to see better.
Here is the ECM low power pulsing the INTAKE camshaft magnet because of low degree of change
The VVT electronic control is amazing , I wish original Xentry C4 or newer can data log VVT at 20hz and I can borrrow one someday to see better ( I am drooling )
with an oscilloscope the Xentry 20hz data will be complemented to see how fast is the PWM pulsing rate of change. DMM is too slow.
Today you're showing Xentry actual VVT positioning.
These details sum up the reality for the trained eyes.
These evidences are essential to understand the VVT Phaser shortcomings not described in WIS design description.
The control pulse is modulated over a 500.Hz low frequency signal.
Only the duty cycle is significant to tranfer variable energy through the magnetic core. It ranges from 10% to less than 50%.
There's a lot of power reserve available to move oil valve through with 90% pulse should the system get weak.
Then what gives... let's have a closer look at what errors in this hydraulic system look like.
We get to see exactly the VVT initial positioning when it is able to move.
unchanged at low Rpm: perfect!
activation above idle jittery while locked
The Surya's VVT lock pin is not worned loose. The position is a solid lock yet the actual position varies around by couple degrees. This is the computed actual number from [CKP + CPS] -
Locked VVT CPS is not changing, what is jittery is the CKP (The ask/get are fixed/unchanged)
sudden reposition disrupting Rpm
one bump plus linear position vs. rpm
"Ask vs. get" position shows a difference about 3degree error. This is the static error the control logic learns to correct to become precise.
The correction is useful to hide any chain stretch by adjusting exactly when valves open in relation to TDC. This camshaft timing manages dynamic valves overlap between intake/exhaust.
...///...
Last edited by CaliBenzDriver; Nov 5, 2025 at 12:47 AM.
It’s really amazing the level of automotive knowledge, technical expertise, and, troubleshooting skill shared by some of our MB gurus with the rest of the forum.
I don’t know if I would ever personally put this knowledge to work with my own hands, but it is very nice to be able to refer to it if needed, and be somewhat familiar with it, so that the “experts” at the stealership don’t take advantage of any ignorance.
I have noticed, that in my lifetime, I have been able to prevent incidents in advance of them happening, from just this type of familiarity.
I just don’t know how many of the stealership technicians have this level of knowledge and understanding.
We were running down the evidences of what CAM. timing issues can reduce our engine driveability.
sidetracked by street scenes
> Minimize camshafts errors...
Normally the VVT Phaser correction helps hide any chain stretch by adjusting exactly when valves open in relation to TDC vs. engine torque demands.
This camshaft timing manages dynamic valves overlap between intake/exhaust.
The errors on camshaft timing are extremely meaningful for de-tuned performance. Rpm jumps as a result of cam timing changes **
The heart of engine timings are the valves position in relation to piston. Even more important than the ignition spark 10° timing.
When the valve timing is approximative, it's exactly like artificial chain slack from loose tensioners. This is one big serious No-No.
This must be ironed out to become a non-issue.
You can help yourself towards precise positioning by identifying the sources of system variables and minimize all errors as much as you see fit.
> What's He Talking About Here ??
This essential topic is clearly NOT unheard of because XENTRY tracks camshaft error rates of "ask vs. get". There should be none of this on new and low mileage engines, be it MB or JP.
MB obviously has knowledge and visibility about this feature, do you think ?
What's rare is having to using knowledge research to deal with status quo without DTC's.
If your low mileage Mercedes acts heavy off the line this is likely the reason why.
Precise camshafts timings are absolutely essential to A/F mixture. None of this is new discovery to engine basics - Finding that on expensive engines is disconcerting.
ECU adapts best to predictable smooth variables else it's an additional wrinkle to iron.
Surya has shown early on what happen to camshafts position when MOD-0 switches the oil pressure low/normal. That's No1 offender with firmware that doesn't compensate for pressure ridge.
This all ordeal is proven experimentally to some extent (MOD-0/1/X) by a growing list of educated folks. I can't put up with the short comings of stock. I'd rather deal with managing unknowns...
There's are many effective formulas the ECU firmware could run to cancel most shortcomings one by one.
Enough ECU updates have gone by that instead of popping new CEL on all failed solenoid harness, ECU code should be more robust to enable solid driveability.
At least there are ways to experimental closing known gaps!
> De-tuning variables:
List of combined variables that should be minimized...
variable low oil pressure vs. solenoid ridges
variable pressure drop when squirters open up
variable oil temperature vs. coolant vs. sprayers
variable oil viscosity vs. temp vs. mileage
variable solenoid chassis voltage
variable Phaser torque vs. camshafts Rpm
Variable significant CKP timing jitter (***)
Variable pressure leaking tensioners
I'm jetlagged in the land of precise-engineering: did I forget any other favorite variable ?? Anything that impact cam. position is a de-tuning factor.
There are programmatical way to filter out these variables smooth so they can't affect engine + tranny driveability.
My rig responds well to oil pressure improvements.
** : my setup may allows for VVT to unlock at lower Rpm so activation ridge does not corrupt throttle position. Perhaps ECU has learned it can effectively unlock sooner with working pressure.
*** : the sealed contributions becoming smoother lower the timing jitter of CKP rotation. That is used in the computation of CAM. position with CPS.
Last edited by CaliBenzDriver; Nov 5, 2025 at 08:54 AM.
Cold start little dance for left bank exhaust been that way since I started logging.
If there will be the final knocking dance, probably it will be the one dancing loud.
Do me a favor,since you are in the US.
Get MB official workshop with their original Xentry scanner to do VVT logging on your car.
The data will be good for us, based on original Xentry.
VVT able to maintain such accuracy for command vs actual is incredible.
A rotating mass having its position set by hydraulic within millimeters left or right side... at such speed is simply amazing.
Cold start little dance for left bank exhaust been that way since I started logging.
If there will be the final knocking dance, probably it will be the one dancing loud.
Do me a favor, since you are in the US.
Get MB official workshop with their original Xentry scanner to do VVT logging on your car.
The data will be good for us, based on original Xentry.
VVT able to maintain such accuracy for command vs. actual is incredible.
A rotating mass having its position set by hydraulic within millimeters left or right side... at such speed is simply amazing.
You always have good concerns when you go in-depth.
I think you have the greatest collection of Xentry evidence for the way your engine is running. Is that a proof of anything?
> You have shown us live evidence of :
squirters opening
solenoid pressure ridge
locked timing jitter !!
VVT activation throttle jump
....
I don't know anyone that has your expertise to instrument valid engine data the way you can! It's too easy to capture irrelevant test data. It would take me too long to get un-biased data.
> SHORTCUT... here:
I have an idea you should be comfortable with... :
Look at the differences between your new PAO 5w40 oil when its new and warm only
vs. when its old and hot.
This will give you an easy test for viscosity impact on what you study.
No need to load 5w50 to evidence some of the viscosity changes.
The setup I am running is an EXPERIMENTAL WORKAROUND, NOT a design fix for MB engine production.
No matter what I do or test will change MOD-X experimental scope is outside factory specs, yes?
Everyone goes by their own priorities within their comfort limits, very well.
I totally agree WE ARE NOT PROVING ANYTHING beyond reasonable doubt either way. I don't care about prooving or disprooving anything for free. Factory service Is The Best stock setup for predictable outcomes.
Ppl can select whatever wheel tires, brake parts and engine oil based on their priorities.
I am not trying to sway anyone so I will not enumerate the list of benefits that are not universal. Not all engines the same!
I believe no one mentioned that M276-TT has both MAF+ MAP where M276-NA has only MAP, right?
The air charge is computed differently - That certainly can explain some differences with VVT response.
> Your "start-up dance issues":
-- What's going on with your EXH VVT Phaser?
Is that Bk1 with the most easy job driving PCV vent?
-- There is definitely something to be noticed with MOD... startups are different in a good way.
The cold starts drop to low idle really fast
The hot starts do the "start /no-crank" (given rail pressure ok)
This is only with viscosity in 15W40 range or greater.
Bk1 EXH phaser gets oil pressure last at start-up
Let me ask what your PAO oil upgrade bring your engine... anything particular?
Did you notice more stable viscosity vs. heat ie. more consistent response instead of lumpy when hot ?
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Last edited by CaliBenzDriver; Nov 6, 2025 at 06:26 AM.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
