freddieb

Hi everyone,
I have a 2013 C250. I recently swapped and replaced a like for like engine because the previous owner seized the previous engine. Swapped it with a similar year and almost same mileage (108k).

The car turns on but the engine doesn’t crank.
I used my foxwell obd scanner to clear all the codes and nothing obvious appears with the engine and tranny.

Do I need to have the dealership or an indy register the ECU to the new engine? Or it it a simple starter issue?

thanks for your replies

JettaRed

iTrader: (1)

So, there is absolutely no crank? I would start with replacing the starter. When you remove the old one, apply 12V to it directly and see if it spins. There is also the old test to hit it with a hammer while someone tries to start the car, but that only works if the car starts. Then you know it's a bad starter. You also want to check to see if the starter is getting 12V when trying to start the car.

If that doesn't work, then take it to the dealer.

Which Foxwell scanner do you have? Is it the one specifically for Mercedes?

TimC300

Did you replace the ecu with the replacement engine, or did you install your old ecu?

If its a replacement ecu I think you have to have it programmed.

Just curious, do you hear the fuel pump turning on, do you have fuel pressure? You should be able to see fuel pressure on the Foxwell scanner.

Is the battery good, tested and/or charged?

Have you checked the fuses? Starter fuse is #7 in the front sam under the hood. https://fuse-box.info/mercedes-benz/...uses-and-relay

JettaRed

iTrader: (1)

The issue is cranking, not starting. Fuel will be a starting and running problem. The car, as described, doesn't even turn over.

freddieb

Thanks for the replies, everyone. Responses are below:

To clarify, there is no crank at all. After I replaced the starter, it turns over but stops after about 2 or 3 revolutions,(probably because the system knows not to continue cranking)??.

>I would start with replacing the starter. When you remove the old one, apply 12V to it directly and see if it spins.
I had the starter tested at my local parts store and they confirmed the starter was bad. So I ordered a part and now the car cranks but now doesn't turn over.

>Just curious, do you hear the fuel pump turning on, do you have fuel pressure? You should be able to see fuel pressure on the Foxwell scanner.
There is fuel pressure. I tested the schrader valve near the driver side bottom of the engine. Fuel spurted out all over my shirt.

>Is the battery good, tested and/or charged?
New battery. I also charged the battery and it measured at 12.7v just before cranking it.

>Have you checked the fuses? Starter fuse is #7 in the front same under the hood. https://fuse-box.info/mercedes-benz/...uses-and-relay
Yes. I checked that fuse and the fuel pump fuse #4 and both are good.

>Did you replace the ecu with the replacement engine, or did you install your old ecu?
I used the old ECU. I am going to ask the guy that I bought the engine from, to see if I can test his ECU (if he still has it)

I also have the Foxwell NT809BT version.

Lastly, there is compression in the first cylinder (gauge goes up to around 30 psi) before the system stops cranking completely.
I do it again and same thing happens. The system stops cranking after around 3 revolutions.

Any other suggestions before I enlist the help of an indy or dealer?

CaliBenzDriver

You have a "crank, no start" with replacement engine swap using your original ECU.
The battery and starter are good.


--- You do have some fuel pressure so let's double-check your spark...
pull a coil + plug to witness spark during crank.


--- Also let's make sure the MAIN GND STRAP at tranny was reconnected during swap - (I know 800Amp cranking current uses main GND) - Just check crusty main GND

--- If nothing else turns up... scrutinize ECU data with a capable scanner.

freddieb

Here are answers below;


> I had a friend of a friend who works for Mercedes and he brought his $30k Mercedes scanner and tested it. He reinitaited the systems to ensure all were syncing up. The only thing that came back was an outside temp sensor and one other thing that wasn’t related to the starting issue.

He thought because the cranking was somewhat slow, the non OEM starter might be a possible culprit but unlikely. He told me to check for spark on the first cylinder with the plug in. And there is no spark.

Any other ideas??

CaliBenzDriver

Ok, you have a well defined NO SPARK on a replacement engine using original chassis ECU.

At this stage we ignore drive authorization with your own ECU.
Top suspect becomes crank sensor.

Don't guess use your own scanner to read ECU faults