CaliBenzDriver

When you can hardly see anything and must work by touch, it helps if you have practice to open the tiny MB connectors.

Working with Spark plug coils is great practice where you can see well up close.

The logic in these connectors is like door locks. There a knob, a lock and a latch... all of that.

Procedure to release MOD1. connector:
1 slide the white lock
2 lift the fragile latch gently and hold it up
3 pull apart the connector body

The hard part is #2: lifting the plastic latch just a little without braking it.
I would recommend using a 90° pick to help release the latch.

If you broke a latch then RTV glue connector should be all right especially in this application - There is No stress pulling things apart, only engine vibrations.
✌️

juanmor40

You can see how the connector is separated at a few different locations

JettaRed

iTrader: (1)

New Compression Test after changing my oil to Pennzoil Platinum Euro 5W-40. Interesting results. There is now about a 15% increase in rpm speed. I did capture oil, coolant, and transmission temps this time (see note in image). Ambient temperature is 78°F. Not sure how to interpret a faster spinning engine. Certainly there is less resistance to compression that the starter has to overcome. I know my battery voltage was 14.4V this time and with a battery charger attached. I do not know the voltage of the previous test, but I did have the battery charger attached then, as well. Master Investigator @S-Prihadi and Master Analyst @CaliBenzDriver , any ideas?


New test results



Previous test results

CaliBenzDriver

Thank you JR, non anecdotal live data is always interesting.
+++ see edits at bottom +++
We do see RPM difference between these two captures on different oils.

Is it better lube or better battery ?


We see the same relative cylinders differences.
I bet a new engine with this test may show similar differences, right?
The significance of the test is indeed relative.

It would be significant to see cylinder differences go flatter from better ring seal, they don't.


What can we conclude with this side by side??
​​​​​​This is definitely a good candidate oil.

Lets do a little brainstorming on how we can measure MOD improvements.

-- I think MAP is going to reflect blow-by none of us TT or NA really like to keep high.

-- We don't all have a complete set of sensors... ppl with true oil temp can measure oil temp vs MOD2.1 spray-cooling at 1500.RPM

++++ EDITS: there are differences...
Let us consider individual cylinders before vs. after


--1-- prior oil mixture

--2-- Fresh euro Pennz


Zooming in close for "apple to apple" before/after cyl. to cyl.:




-- Cyl.1: small difference
-- Cyl.2: bigger difference
-- Cyl.3: small difference
-- Cyl.4: small difference
-- Cyl.5: bigger difference
-- Cyl.6: bigger difference

> HOW IS THAT.... ???
-- A difference in contribution improvement.
Cylinders that have a better seal contribute more.

-- Wait..nope! This test is free spinning without fuel, so there is zero contribution, right?
Difference are all about friction drag and leaks.


> TEST SIGNIFICANCE:
What is the significance of a cylinder free-spining RPM before/after oil change?

-- What we do see is lower RPM cylinders change less after oil change.
-- Cylinder with higher RPM improve more!


-- What is counter intuitive here is LOWER IS BETTER!
- Lower RPM means more efforts against free-spinning.
- Either a better seal or more friction.

- Ultimately this test is showing relative compressions without fuel.
-- Cyl.1: contributor
-- Cyl.2: follower/leaker
-- Cyl.3: contributor
-- Cyl.4: contributor
-- Cyl.5: follower/leaker
-- Cyl.6: follower/leaker

What we see is contributors don't change much RPM between the two tests sessions.
Based on that I would hope rings keep improving... I don't think this is showing leaky valve seats, right ?

Wet cylinders improve dynamic seal.

JettaRed

iTrader: (1)

Correct. This is entirely measuring the resistance from compression and the lubricity of each cylinder. Faster spin=less resistance. Warm oil no thinner than 40W. But both Mobil 1 and Pennzoil are 40W on the warm end. However, there are statements that Mobil 1 actually thins out to 30W.

So the possible variables are oil and engine temperature, battery voltage, oil brand, and actual viscosity. Higher ambient temperature is less dense air, but really doubt that is it.

CaliBenzDriver

We see second test spins a little faster than first one but considering that higher RPM are worse cylinders.

I got confused at first thinking that higher was better.... I think it's the opposite, like so:

Cylinders with better compression spin slower in this zero fuel no-contribution setup.

Cylinders with weaker compressions spin faster.


In this test, higher RPM cylinders are weaker than slower ones, yes?

I don't think this test can show the drag differences between oil1 vs. oil2.

What we really want is even cylinders contributions so the timings can be extremely predictable. ECU injects cylinders individually to help even out contributions.
Learning those data requires ECU driving time.

+++ 20HP on V8 +++

When Lake Jr. wants to showcase his slim rings that saves 20Hp friction on a Ford V8, he compares the dyno output.

He calls that difference very significant.

Difference of Oil1 vs. Oil2 I doubt can be picked up by compression test.

There must be a better way to instrument differences...

Without sweating too many bullets with test significance, we know which direction things go... that's the method I've used.


It's fine to evaluate compression to see how cylinders evolve with cleaner wet rings, right?

JettaRed

iTrader: (1)

@CaliBenzDriver intuitively, I agree. However, step back and look at what is happening. 1st, we are not doing the test in a controlled environment, meaning that I did not capture various temperatures and battery voltages in the first test. 2nd, faster spin means less resistance (or greater voltages), either to less compression, less friction, or both. So if compression is the same as it was only 5 days and 108 miles ago, less resistance could be the result of better lubrication. The speed difference is around 15%, which is significant in my uneducated opinion. I don't see compression loss in 108 miles equally across all cylinders. As you observed, the relative differences between cylinders did not change much.

W205C43PFL

Thank you, I agree guess I will get a helper and try to get this done this weekend, as I have a injured back I will need some help if going from beneath.
Is there a specific borescope you recommend by chance?

Thank you! I will keep this in mind.

Appreciate the video, might help out thank you for sharing.

JettaRed

iTrader: (1)

This is what I used: Teslong NTS300. I had gotten a cheaper one before, but the camera was not a clear. So, I returned it and got this one. Dual lens, straight and side views.

W205C43PFL

Perfect, thank you!

JettaRed

iTrader: (1)

Actually, it's cheaper direct from Teslong. Also, the one from Amazon has a 16' cable, which is way too long for automotive work. You can order one with a 1m or 3m camera cable. https://teslong.com/products/nts300-...39733693579377

NOTE: When you register with Teslong, you get a 10% discount on your first purchase. Wish I had known this! With the discount, the price drops to $113.39 plus shipping (about $8).

W205C43PFL

Ah, I see. It is shorter, that explains why it is cheaper. Thank you! Perhaps you can find something you might want with the 10% off you get from registering?

JettaRed

iTrader: (1)

Actually, on the site, the 16' (5m) cable is less than the 3m cable.

TomZVB

Didn't MB discontinue usage of this particular diagnostic test?

CaliBenzDriver

Yesterday Master @S-Prihadi and myself were out digging stuff about VVT troubleshooting when I stumbled on a smoking gun Surya had just tossed over his shoulder -
​​​​​​
We saw the VVT gear Offshoot timing no less two times times 4x units.

Once above idle and secondly at 3500.RPM.
This is no joke, it's a Mercedes!


Now we are deconstructing poor acceleration caused by oil surges. Say we try ironing this chaos with MOD.2.1 - - lets atch more hummingbird easter eggs.


VVT Overshooting from starved idle pressure


3500.RPM Pressure surge overshoots VVT



super lazy flat VVT across RPM... only used to correct chain stretch??

This hints you that ECU does not expect VVT to change timing - No algorithm to track active change. When that happen HPFP gets off beat and pfessure dips. ..... anyone familiar with poor pressure under acceleration now you get TORQUE when HPFP plays on-time.
Beats low pressure lag, easy?

I believe minimizing these abnormalities improves steady HPFP timings.... yeah Duh !

Now go read the source thread here.


caught 'N released like our engines
When diving with Surya we always find pieces of puzzles.


Thanks to @BenzNinja for empowering his members to use sweet software suite.

W205C43PFL

Ah, good eye! Thanks again.

JettaRed

iTrader: (1)

W205C43PFL

Forum member JettaRed, and others who commented on my replies including but not limited to how to unplug the connectors, a video of it, again I appreciated everyone's attempt to help. So I went to tackle this project again the weekend that went by.

Sorry for the disappointing update but I still wasn't successful.

I am jealous that you were able to get it unplugged from the top for the M276 turbo model with the intercooler in the way, I even went down, placed the car on ramps and dropped both underbody panels to try to unplug it, I can barely see it but the borescope helped shine a light to it. I then tried to get more ground clearance by jacking the centre jack point then placing jack stands on both sides of the vehicle.

If I look straight in, the rubber coolant hose is in the way, if I look at an angle the silver coolant hose (or part of the turbo? that connects to the intercooler is in the way). My hand doesn't fit. Used a hook tool and didn't help at all.

The rubber coolant hose at least I can slightly bend and without damaging it but the silver one is metal. That said, even bending the coolant hose slightly away doesn't help, I even accidentally removed the white clip to the connector. Now how would I be able to unplug it without the white clip?

How did you managed to tackle this without removing anything, including but not limited to part of the subframe? Here is a picture of a phone camera pointing from the bottom. That connector is hiding right behind that coolant hose as you know.

I thought of removing the ziptie to the rubber coolant hose to move it away so my arm can get inside but then there is the plastic holder thing as you can see so it will be in the way still.

S-Prihadi

I have to remove my aftercooler if I want to access that connector. W212.065 E400 RWD

Seen without aftercooler. Ebay photo.


The oil pump solenoid connector in green circle.



My engine. Use water pump input hose ( red cap if at above photo , red arrow at photo below ) to imagine connector position.




Aftercooler removed.





My type of subframe will not allow hand to access the oil solenoid from under the car. If aftercooler is not removed.



W205.064 is 4 matic. The subframe probably more "crowded" / complex. less access by hand too.

JettaRed

iTrader: (1)

Darn! Sorry you couldn’t get it done. Viewing (seeing) the connector is nearly impossible. You have to do it by feel and visualizing what it looks like and where it is.

Disconnecting the coolant hose may be an option. Changing the coolant may be good depending on how old it is. BUT, the process is to vacuum fill the system to prevent air pockets. These YouTube vids on how to do it.

W205C43PFL

Thanks for the pictures! Thank you for correcting me as well : ) aftercooler not intercooler I meant, which makes more sense.

True, I do have 4MATIC and forum member's SL 400 is RWD, that might complicated things indeed.

W205C43PFL

Ya : ( it is so frustrating I can literally see it with a light on and the borescope but my arm is too short and my tool is not working with me. What made it worse was that I broke the locking pin/clip. Well, it isn't broken just came out but I have it in my hand which is not where it should be.

How do I proceed to unplug it now without that locking pin which I would had been able to press down on and pull the connector off if it was there?

Thanks again! Really do appreciate all the pictures and the help with the explanations and recommendations.

S-Prihadi

The correct name would be CHARGED AIR COOLER
But I don't care INTERcooler or AFTERcooler, as long as you know which one I meant ....its all good.

W205C43PFL

Yup, I know which one you are talking about : )

Thank you!

As my understanding this clip has two locks/latches. One is the sliding pin that slid off (in my hand right now), the other is the grey one on the rear which the sliding pin would had kept it in place, with so little clearance, I had trouble getting my tool to the back there when doing it from the bottom.

From the top, like how forum member JettaRed was able to do it, I did feel the connector but sadly my arm was too short to reach enough to unplug it, from the bottom, the water pump hoses, coolant lines and of course the aftercooler were blocking, the subframe wasn't helping either. Now I even pulled the sliding pin off so the only way to do this is to find a way to get a tool in there again and attack from the back.

CaliBenzDriver

You know you could simply cut one of the two solenoid wires and be done under 5mn .... unless your ECU is the type that pop the CEL on dash then you may prefer an optional "dummy load" replacement coil, plugged-in or soldered to pigtails.

++++ HPFP proportioning valve

high pressure pump control
Link to TIMINGS description....