dan222000

Hello,
I'm having a no crank no start issue with my 2011 E350 Bluetec. This is my wife's car so I don't normally drive it. We've had it for 1 1/2 years now and it's been a great car but recently my wife was driving home and the instrument lights came on and the car started running rough. She pulled over and turned off the car and tried to restart it. The car would not crank at all. I had the car towed home as I am mechanically inclined. I checked the battery voltage and everything seemed to be in order. I would try and start the car and nothing, not even a click from the starter. I checked the fuses and starter relay. Fuses good and relay is clicking. I then tried to give the starter power directly from the relay #87 & #30, Nothing not even a click. Checked for power and I have power at the relay. So I ordered a new starter, put that in this weekend and it cranked slowly and would not fire. Went and bought a new battery and tried again, it still cranked slow and would not start. Eventually after trying 3-4 times the starter stopped working again. This is where I'm at, any ideas what else could be going on?

I ran my MB cheap scan tool and no engine codes. Any help would be greatly appreciated.

Thanks,
Dan

CaliBenzDriver

Good job narrowing things down all the way to here:
New starter & new battery but still slow crank.

I assume your battery is well charged up to capacity so the issue is likely a poor main batt GND path.
​​​​​​1-- Oxidized chassis GND strap (chassy-tranny)?
2-- Battery GND strap to chassis post ?
3-- Battery connectors oxidized?

100% of the 600A cranking current returns through this GND connection.
Starter power does not route through the prefuse block.


> TESTING:
Use a DVM to measure or a test-lamp to visualize the drop voltage between the batt (-) and the engine block while cranking.
Expect something around 3 to 4 volts where realistically you'd want a number well below 1Volt drop Max.

Because of the extreme current, a marginal single connection occurs an extreme voltage drop ( U = R x I ).

The low voltage condition helps overload the related electrical connections with high currents thus always keep your battery charged up.


> Need to go now... ?
I bet you can easily bypass the GND connection by using half of your jumper-cable!

Here is the link to... HOW YOU MAY PROCEED


Bypass poor connection by self-jumping!

​​​​​​​The amazing issues developing from the single GND strap, really call for maintenance plus a second and third strap for reliable DC power.

dan222000

Thanks for the fast reply! I pretty much already tried the ground strap method with jumper cables to the engine lift point/hook, I'll try to find a good spot on the block as shown on the photo you sent and report back. I also used the ground post near the passenger side strut tower near the battery.

dan222000

Could it be the Pyro/Pre Fuse? I understand it sends power directly to the starter? is there a way to check it?

CaliBenzDriver

yeah you want to bring the BATT (-) to the engine block where starter needs it.

Live the (+) side alone, it already has a good direct connection to the starter.

Of course you need the battery post connections fastened, not loose... just checking

CaliBenzDriver

Here is a junker an old favorite featuring Mercedes GND solution:
GND STRAP is not very glam' but essential for the HEART FOR BRAIN FUNCTIONS.
✌️

​​​​​Taking 5 mn is time well spent to learn about this old favorite. It did not go out of fashion because MB is using poor GND to deliver fish-bites transients to its amazing electricals.


Nothing's good enough here to ZAP YOUR WHOLE CAR with super glitches ... let's see what the 100A PWM fan can do /

FYI: The battery sensor display shows battery voltage with limited reference to engine GND. Drivers can not directily see the oxidized strap glitching.

This is wise video of a sibling Pontiac with cheap single GND strap exactly like this W212 & many more sweet troublesome premium sedans...

Fix this sweet bug only if you own the car, else let this rain awesome busy work.


Rebooting has never made more sense to loose the accumulated glitched stacks in F-SAM.


Ask to fine tune the poor GND
then enjoy days without computer glitches and beeping dashboard errors.

Anatomy and genesis of GND STRAPS modern troubles...

dan222000

OK so I checked all my grounds and they all seam to be in order. I also performed the jumper cable grounding technique directly to the engine block and no change. I am suspecting the F32 prefuse box as while I was trying to start the car after the new starter and new battery replacement my brother observed a small cloud of smoke from the prefuse box. My next step is to remove the prefuse box and test the fuses. Can the prefuse box fuses by purchased individually or is the entire box only sold? Anyone have a good source besides Mercedes fro the prefuse box or Fuses?

Thanks,
Dan

CaliBenzDriver

Okay, I see we are dealing with more than a starting issue here... it sounds like you have a short circuit that's causing a genuine low-battery voltage.

Remember to recharge your new battery to preserve it from premature lead sulfation.

The prefuse box is not involved with starter power per-say BUT starter control certainly as Prefuse dispatches power to the whole car.

As far as buying spare links, it's hit and miss success rate... I am sure we can find a satisfactory way if you don't need everything fixed yesterday (new, used, spares links).


> Figuring The ROOT Cause :
The best option here is ... not roasting many fuse links like marshmallows ...

-- We need to observe the damage to understand the issues that caused it.

-- Before having to trace a schematic remotely, let's first go over a few favorites off the obvious list:

- How is the AUX Battery condition?
- Any signs of FLOOD damages?
- Any custom electrical TAP for audio .... ?

-- There's a chance Prefuse bolted connections may have gotten loose and oxidized without a short-circuit. Let us see what this looks like inside if you will.

-- K2 Main Relay lives inside the Prefuse to disconnect battery from the main circuit at cranking time. It's one of the major path to consumers.

-- Get the schematic for your VIN handy.

Let's see what pans out...

S-Prihadi

Try to spin engine by hand first, from the main pulley.
It is internally having massive friction as such the started overloaded ?
Check engine oil level from fuel dilution, just in case you have leaky injector which is flooding your chamber and surely very heavy to crank.