mssaddleback

2011 E350, 135,000 miles is exhibiting an occasional long crank, usually 5-6 seconds before starting. It was happening once in a great while, now it's more like 25% of the time. Could it be a cam positioning sensor begining to go bad? Otherwise the car has been bulletproof, new plugs at 100k mi, other maintinence up to date. What am I missing here?

CaliBenzDriver

Look up your fuel pressure using your scanner and scan the chassis faults for additional clues.

If there is a difference between engine cold vs. warm engine this will help sort the issue between fuel vs. cam sensors.

Any oil leaking out of cam sensors?

Arrie

In my 2010 E550 it was the starter motor. Changed battery twice for the problem but it turned out to be the starter.

mssaddleback

No difference between cold vs warm. Can start right up when cold, then on the way back from somewhere with a warm engine it could fall back to a long crank. Also, this is a So Cal car.

Also, it seems like the starter motor is fine, it's just that the engine is not lighting up. Also, I discovered that while the engine is cranking, I could take my fingers off the key and it will continue to crank until it starts.

CaliBenzDriver

Your long-crank is interesting because it's a bit inconsistent.

So this is aiming more towards oily Cam sensors than fuel but double-check pressure. In tank pump/filter may still be main suspect.

Any misfires show up when fully warmed up ?

Also check DTC faults for CKP clues.


Starter short-brush is sudden and causes slow crank not randomly long. It's got two pairs and one of the four is setup to fail.
​​​​​

Arrie

So did I think as the starter was turning the engine fine every time but sometimes took several seconds to start.

There is easy way to prove this if your long crank now happens daily or weekly.

Charge your battery full, I mean good charger on it overnight for so long that battery is completely full of charge. Then use car as you normally do and see if the long cranks disappear for a couple of weeks, but then return.

My theory here is that the smart charging system in these cars let battery charge go down that then bring the starter induced issues when starting the car. Bad starter robs power so bad there is not enough of it for all the modules needed for starting the engine. Fully charged battery has enough power even when starter is giving the issues but when that charge in the fully charged battery goes down in a few weeks the problem returns.

When I had the problem I first had the battery changed at the dealer for $400. Problem went away for about a month. I then went and replaced the battery again. This time with an AutoZone one and exactly the same thing happened. Took about a month and long cranks returned.

A very similar thing to your experience was that with cold engine start was normal but then with hot engine long crank was there. You would think hot engine starts easier…but with compromised insulation in the starter heat will make it worse.

I came across info in this forum about the starter being the likely culprit. I went and got me a cheap starter from AutoZone and this completely fixed it. This all happened 6 years ago and I did not have any issues at all until two weeks ago when long cranks came back but this time it was the battery I got from AutoZone. I still had the $400 MB battery and installed it and all is good but I’m afraid this battery will not last very long even when it has not been used. It is 6 years old.

Long cranks are symptom of the starter going bad and one day it will not crank at all.

S-Prihadi

If your cranking RPM is 180 - 200 and that does not start the engine within 1-2 seconds in say 20C ambient temperature, starter and battery issue is not the problem.
180-200 RPM means battery is decent or good.

Yes, our ignition key is an electronic command and not true mechanical command. So the actual cranking is timed by the module even though you do not keep pushing or turning key to CW.

Arrie

With all due respect, I disagree with this statement about the starter RPM. Mine did just normal crank speed with long cranks.

After I removed the bad starter, I tested it using 1.0 mm dia wires connected to the new MB battery that I had replaced with the AutoZone battery. The wires were glowing red until one of them burned. This is how much amperage the starter took just turning itself.

S-Prihadi

Did you measure your cranking speed during the problem you had with long cranking ?
I doubt you did.
Two ways to measure. Use average cranking speed using Xentry Compression Test, or using a scope to read CrankPos signal raw .

Well starter motor is big power sucker.
When it is zero speed to actual designed speed, it has to go thru LRC, Locked Rotor Current, that will take approx 600+ amps when scoped or 570ish amps
when using current clamp with INRUSH function, which is slower data reading than a scope but it is industry acceptable speed.
When it is already spinning ( with engine load ) to start the engine , a normal healthy engine M276 will need approx 220 amps.

So what could happen in your case is, a not so healthy starter eating up LOTS of battery power while not doing fast enough 180-200 RPM.
So not only the engine spin is too slow for first say 2-3 seconds, your battery voltage drop is massive too and the engine and tranny and Ignition key modules can't get proper operating voltage...yet.
As the engine spins and spins past 3rd second , the electrical load a bit lighter and then your engine actually managed to start.

Arrie

All starting problems went away with the new starter. That is all I can say.

CaliBenzDriver

Around what mileage did your starter give up?
Did you replace it yourself, from the underside right?

CaliBenzDriver

MS, you know there might be more to that story about cranking these M276/8 engines. Starting is not as simple as it used to be with carburetors.

We can either get mad about engineered chaos or make sweet lemonade with it - Which is it gonna be ??

A few month back, I noticed my engine cranking had drastically IMPROVED while some ppl report abnormal cranking issues...

So here, I am wondering if the two can be linked by what Mercedes Bosch created for us.

Meaning brilliant design owners crafted a new factor that can either strains or help the engine starting process.


(This is regardless of battery or starter being in normal condition - No miracle with junk, duh.)

Laborious extended cranking is what chews up the ultra-soft carbon brushes and crumbles the battery plates in the process. Nice sweet bu

A great crank is when the starter shoots up the engine straight into high RPM. Either by cranking the conventional way or "start no-crank" by ONE single compression.

Mind you, I am getting that from my 11Yrs old battery ie. not the strongest crank amperage in town... quite the opposite, right.
In other words, I have a questionable battery and a 60kMi starter that deliver remarquable moonshots.


So what are the factors involved in crank quality:

• WTF secret strap doubled up for low drop voltage
• HPFP accurate timing for tuned injection
• Normal starter/battery (vanilla grade)
• Wet lubricated engine (not only dry-lubed)
• Minimized electrical issues (GND, solderless)
• ....

These excellent cars are carefully built with a collection of engineered defects. Cranking is only one example.

S-Prihadi

Surely the ignition readiness air+fuel+ignition and all sensors in order ,,,,,,,,,,,,,,will speed up actual engine crank to start of engine.
Amazing your 11 years old battery .

If crank to start takes more than 1.5 second, for me I will start finding the fault already as that would be Abnormal for my engine.
Usually 0.5 second is my crank to start duration.
Based on no cooler than 18C ambient temperature, the coldest my car been in ...LOL.
I can't imagine thick sticky oil if at freezing Zero Celsius or colder.

Often crank-pos sensor weak signal may make long crank to start , ECM will then use Cam-Pos sensors as alternative.
I do not know the threshold limit for DTC to be triggered if indeed just simply a weak crank-pos signal.

CaliBenzDriver

let me finish my dinner then we can hammer moonshot cranking.

HPFP timings involved!


High pressure GDI pump

BenzV12

We had a similar problem with what Arrie said before. It was not a Mercedes-Benz but the problem was same as described . Battery and starter replaced and no more long cranks . Aside from that , if long cranks only occurs when your engine is warm then it might be a fuel pressure problem as well .

CaliBenzDriver

Yes, that totally makes sense:
an old starter loaded with soft carbon dust short-circuits it's battery.
Both get cooked prematurely and everyone goes home happy for a while.

The question is what sort of high current wasted the brushes ?

You know when voltage is low current goes up to deliver power... exactly what abuses everything in starting path.
This is factored as: P = U x I

​​​​Meaning... charge your battery or pay for it.


​A good friend of mine was a die hard V6 transversal Ford Taurus fan. He was a bank loan officer driving distances seeking his bonuses pay.
He well expected his car to brake down regularly but was getting great dealer service. So everything was normal just like us with what we got: mandatory high maintenance.

When I told him about Honda/Toyota only needed gas and oil, he was in disbelief. How could Japanese cars be better that once legendary Detroit city.

He had no idea man made chaos was unavoidable then he got a Honda and now he drives a BMW.... It's all about expectations.

CaliBenzDriver

So we were saying that starting M276/8 engines can be good for a while until the starter cooks the battery.

Personally I found out this does not need to be.

Instead some of us can get "moonshot" start with an old starter on an old AGM launching the lubricated engine into high RPM.

So there's a big gap right there. Either you enjoy the luxury money-pit experience or you look for answers.

The bad news is the fix is not up to me, Master Surya or yourself... it's up to your ECU only.

You have to void your warranty to set things well so your ECU can run your engine better.

Moonshot starting is an unintended consequence to having great Bank1 intake timing with MOD2.x

Clunky starts are the norm, new battery, new starter once a while who cares

Whatever luxury Mercedes sold 1st owners and did not materialize is in there ready to be enabled for free.

+++ HPFP interworking +++

HPFP
We see the high pressure pump is controlled by an ECU solenoid and actuated by the camshaft lobes. These two better work precisely together.

On the outlet side towards the rail we have two check valves as noted by MS as 1 + 2.

On the onlet side we have a proportioning solenoid valve driven by PWM cycles to control pressure.

The fuel pump piston is forced up by camshaft roller following steep lobes to compress high pressure.

We have a controlled inlet and an automatic pressure outlet.
Now let's consider the interactions of pump piston, inlet and outlet. We have no control over the two outlet side ball on spring valves.

The only control of this pump is the opening of the 70Psi fuel inlet through proportioning solenoid. This has to match the travel of the the pump piston.
Essentially this is like an engine inlet valve.
The timing has to match the surrounding mechanicals.

The PWM pump solenoid must open when pump piston travels down and hopefully **** when piston travels up to compress liquid gas out.

In the details the pulse width is in charge of opening the pump inlet valve based on what the ECU calculation requires.

If that doesn't not happen then the pump simply draws from the existing pressure through valve No2. No new gas gets added until cycles allows in additional volume into pump.


> WHAT CAN HPFP IMPACT:
When the proportioning valve is delinked from the piston....rail pressure simply drops as fuel is getting consumed by piezo injectors.
However we see that the minimum pump pressure is that of the rail by virtue of No2 valve... if prop valve opens any time outside downward intake stroke, pressure can leak through towards the tank.
✌️
(lets not talk about blowing tank seals here)

Instead:
"WHAT DO WE WANT... WHEN DO WE WANT IT*

We want the solenoid to jokey the pupm valve open on stroke down ONLY. Okay:
How to keep timing in synch?


Order of controls may be:
--1-- VVT unlocked kind of adjusted angle

--2-- ECU doing the pulsing on schedule only a fine amount of additional pressure.

Srewing that up guarantees a penalty by Lambda or a plain lean when ECU quit playing... ECU's middle finger lol
(screws up lean accelerations.

This is the kid of chaos the ECU IS DESIGNED TO DEAL WITH but not to our advantage so we want to help the ECU stay in GDI MODES... cheap oil pressure!


My goal is to minimize that and so far I found BIG hidden nugget ( torque, temp, pwr, brakes, velvet shifts, Normal G1-2-3, (consistent hot/cold)


Here is once upon a time a pair of worldly PADI dive buddies spotted something in the murky distance...

--- > the "crappy cranks": suggested interests:
1- oil pressure above MOD2 + 300ml
2- chain tensioners
3- smooth running sealed cylinders
(...??...)
4- we may still miss basics like (ALT, STRAP,...)

In other words, bad timings >>> poor starts!
Experimentations starting nearby: "5W40 +"


In this section the only one grading your engine is your Bosch ECU...
Try to make your engine fit within ECU boundaries!

You setup rhe engine, ECU mesures its performance dynamically.
The Engine Control Unit likes regularity, opposite of misfire.

Gota have firery normal Bosch working spark, nothing fancy. Bosch fly's. The ECU has many ways to deal with marginal timings.



+++ As far as long cranks OP: Check fuel pressure and colapsed tensioners.

S-Prihadi

I miss the day of tuning carburetor engine.
My dive compressor uses Honda single piston 6.5HP multi purpose gasoline engine, this type :



I can tune it as such it will surely fire with 1 pull from COLD or WARM.
If COLD, I only need to open CHOKE 50%, if WARM no need to open CHOKE at all.

My 1 liter carburated Toyota. Manual tranny.
Engine easy start test I love doing is : get a mild sloping down road. Kill engine. Apply hand brake. Car will stop.
Ignition ON, but no need to crank. 1st gear chosen, clutch depressed. Release hand brake, car will roll so very slow,.......
release clutch, engine will fire immediately...I love it when it get tuned that well. I think it is less than 50 RPM crankshaft to kick start the engine.

I do a lot of engine start on small 25 - 30HP outboard using hand pull. 2 stroke engine back then.No battery needed.
When the tuning is not optimal, dang my hand got tired. I need to do like 3 pull.
Older 200HP Yamaha 2 stroke outboard also have emergency hand pull facility to start it . But heavy.


Now modern engine, true as you said Cali. ECU will expect all parameters to be OK before engine start ( ignition On ) and while engine cranking, up to engine running.
And then how smooth the idle is after very 1st firing of engine to its RPM settling down to normal 600ish RPM....maybe 60 seconds window.

The key is maintain the engine with love. There then 0.5 seconds cranking to engine running one will get.

Arrie

I don't remember the exact mileage. I think it was around 100k miles, car now has almost 190 000 miles.

I bought starter from AutoZone and it has been working fine. I remember this starter was physically longer than what the car came with but it fit in.

I did the change myself under the car and I remember it was a trick to first fit the old one out and then the new one in, but it all worked out fine at the end.

MRLE550

Had a similar issue with our E550 and GL450, both times it was the starter. Starting the car was night and day after replacement and have had zero issue with either for years after.

matt