MerchantM5arine

Idle may be quieter, but I've always thought I had a pretty quiet idle to begin with. Its definitely on the quiet side of the M157's I've heard. The temps under the hood feel 50 degrees cooler to me, that is shocking enough. I work in an engine room and me and my watch-standers are hyper sensitive to touch, feel, smell and temp. The engine just feels happier, less stressed.... proper lubrication will do that to a motor. The lack of oil pressure gauge always irked me for a high performance engine, that's my next goal, is getting one fitted. I actually have one from 63 motorsports, but need to find the time to run the cable and find a nice place to mount the display.

TomZVB

And more from LN Engineering… might be better than reading. Porsche-centric, but alusil/silitec/lokasil/etc are all doing the same thing. Three parts….

TomZVB

I listened to one where he’s talking about the wear differences between Castrol GTX and Castrol Classic. The higher zddp and detergent of the Classic kicked the GTX’s butt. Was there another on I needed to look at because he seems to make the case for more zddp.

kevm14

Yes I want to say a more recent one on Pennzoil Ultra Platinum. Their GTL oils are very interesting.

CaliBenzDriver

Some of us are familiar with
-- NO CRANK / NO START
-- CRANK / NO START
Around 1500.Mi you may be graced with :
-- NO CRANK /START!!

The MED17 litterate folks know about the crankshaft sensor having a high resolution and how the ECU saves the exact crank position before powering itself down - That's all pretty amazing but until today I had never encountered that.

Today for the 1st time my ENGINE JUST IGNITED WITH NO CRANKING.
It's like: bam > idle !

I guess it really needs to get one good compression to launch the rest of the engine.
The ECU has a precise logic to know what cylinder needs to be injected how much to get multi-spark ignited.

Of course you'll need to have enough HPF stored ready for action., such as less than a 30mn stop and a hot engine - Best use case is ECO, short stop.

Every pre-condition needs to be right else expect a conventional short crank to pump up high pressure.

kevm14

Oddly enough I experienced that more before pulling the plug. But it's been colder. I think a warm start on a warm day was most likely to do the insta-start. I did think that was cool and I attribute it to part of the overall stop/start engineering to get the engine started as quickly as possible. The car is going to become a garage fixture as soon as the first salt goes down so 1,500 miles is going to be way next year....

CaliBenzDriver

I have had the "ignite style" only once today. Other starts were easy cranks launching the engine high into idle. Even that's a new way I wasn't used to before.
I guess the "ignite starts" are going to happen more often with better mixtures, slick cylinders and better compressions.

​​​​​​Do you want some homework to practice your soldering iron skills during salt-season?

TomZVB

I’ll check it out. Thanks!

BDC90

Yikes, I pulled the plug and there is oil on the wiring harness side. Now what do I do?

PeterUbers

Check the ecu pins for oil... this is another place for oil to wick into the engine harness. Disconnecting with no plans to re connect it essentially solves the issue but if you plan you re connect you'll need to replace the solenoid/sensor

BDC90

No oil in ECU , replaced CPS and added pigtails to magnets awhile back. If there is oil on the pressure sensor harness won't it leak oil all the time ? Or only when in " low pressure" mode?

BDC90

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?

BDC90

The sacrificial pigtails I got from FCP Euro are the same connector.

PeterUbers

totally fine to use then

BDC90

Seems like they should plug the leak and protect the wiring hrness end from damage. Thanks for talking Me off the ledge.

ImolaSix

I wonder if unplugging the pressure valve to increase oil pressure during low/moderate load will accelerate/exacerbate the oil leaking past the cam sensors issue?

juanmor40

Recall the oil solenoid has been described by MB a NON essential part to the 4 cylinder engines. Only because it was exposed because a g
high failure rating; otherwise, there would have never been a TSB

also, do you think that low oil pressure between 600->2500 rpm is beneficial for these engines?

BDC90

After close exam of the sacrificial pigtail, it doesn't look like it will prevent oil leakage from the oil pump solenoid. I need to determine if the soleniodr leaks all the time or only when it's restricting oil pressure.

Mojo20032004

Do you think it's a good idea to have a dry engine when your car is making 700-800ft of trq at 2500-3k rpms.. Imagine how much heat gets applied on the pistons and rods when that torque kicks in

ImolaSix

You're missing my point. Oil leaking past cam sensors and into the harness/ecu is a known issue with the M157 and some other models as well.
The higher oil pressure under low/moderate load should be beneficial however it's still worth considering if this will accelerate the process of oil weeping past the sensors and into the harness.

JettaRed

iTrader: (1)

So, add the sacrificial harnesses to your engine and don't worry about it. You should have these on anyway. There's a reason Mercedes makes them.

https://www.fcpeuro.com/products/mer...des-2711500156

TomZVB

It may actually have the opposite effect. The seals will receive more adequate lubrication and hopefully promote a longer life. This could be especially helpful with new seals. Older - ymmv.

CaliBenzDriver

Most of us want the good without the bad, true?

Let's not bunch up too many things together. This is the formula used to create "snowballs": in the end no one is able to understand a thing.

> Replace known leakers after inspection and change engine oil/filter as usual.

> Normal oil pressure is no replacement for good maintenance. (the next thing you know... the advisor said it caused oil in my $10,000 ECM repair - )

> I read this on MBWorld: **¡ DON'T DO IT ! **


> LEAK SOURCE :
First of all, if you don't like $10k "oil-in-harness" deal with toasted CPS sensors and check VVT Solenoids ASAP or before misfires call your attention.

> OILING GOODNESS:
--1-- Normal unlimited oil circulation lowers heat in both heads and prevent toasty plastics failures.

--2-- In addition crankcase pressure will be reduced by less blow-by wet ring seals and no vaporized burned oil. This is witnesses by vacuum brake booster improvement and oil consumption back towards zero.

->> These 2 factors should essentially cancel chances of $10k surprise if you start ready. Proceed under your own supervision and understanding that we know less than you do.

-- That is not to say you should ignore plastics already on the edge of disaster.

-- The sacrificial pig-tails are easily replaced if/when oil leak is found . They do NOT prevent oil migration by capilarity. Only good sensors can do that!!

Like I said elsewhere this is one spaghetti ... our friends have been busy spinning other amazing opportunities.

Happy Thanksgiving holiday ✌️

ImolaSix

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.

BDC90

So My question is still. Will the oil pressure solenoid leak oil if it's unplugged/ deactivated?