dana.jackson

I need help please.

My ML320 would not start after driving it 3 miles, shutting it off to run errand and tried starting back up 15 minutes later. It would crank but not start. No problems whatsoever before this. We have replaced fuel pump, still cranks no start. Then replaced Crank Shaft Position Sensor, cranks still no start. Then found 3 coil packs were not getting spark, replaced those, cranks....still no start!

What else is there?

Maj. Dundee

Which coils did you replace? Were they all on one side?

dana.jackson

TY for asking. We replaced one on the driver's side of the engine and two on the passengers side of the engine. My son in law did this and he said if you are standing in front of the vehicle the coil closest to you on drivers side was replaced and the two last coils on the passenger side replaced.

Do they all need done if there is some spark?

dana.jackson

should i have replaced all 6 at the same time? and 2 of them were different brands than the 3rd. does that make a difference? is there a security code to reset for this problem? I'm so clueless and have googled for 2 weeks now and called dealership....they say bring it in and pay $250 so they can tell me whats wrong.... any help/ideas is much appreciated.

Maj. Dundee

No you shouldn't have changed all 6 coils. As a matter of fact I don't think you should have changed any.

What are the odds (bigger than winning the lottery) of three coils going at the same time, especially after running an errand?

Hints:

1. Fuel pressure (checked with a gauge).

2. Fuel filter.

3. Check fuse #26. With key in pos #2 both contacts must illuminate a test light.

4. If fuse #26 is OK, turn key to pos. #2 and with a test light probe the Blk/Grn wire on each coil on the R/S (passenger) and then probe the Blk/Yellow wire on each coil on the L/S (driver's). Remove each connector and check for voltage on the connector pin. The wires mentioned are the middle wires on the connector.

5. Where did you get your Crank Pos. Sensor? Anything other than Bosch, you made a mistake.

yourbenztech

Under the motor plastic cover on top of the motor on the front section there is a little nipple that looks a lot like the AC charge but smaller , I believe there is a little screwable black cap, remove the black cap and take a little screw driver and push it in, see if fuel is coming out and let me know so we can go to the next diagnosis.. if fuel is not coming out and you do have new pump, we will need to check electronics..

Rumelflowers

Hi I bought a ml two weeks ago and already having trouble ! Starts first thing in the morning fine but when I turn off and try start again it doesn't want to I have no idea what this is and yesterday it's starts to stall when in traffic .

Maj. Dundee

You must change your Crankshaft Position Sensor. Buy a genuine Bosch sensor at a parts store.

Here are the instructions and location.

https://mbworld.org/forums/5217194-post2.html

https://mbworld.org/forums/5645497-post2.html

Rumelflowers

Ok thanks I will try that

yourbenztech

Do you have a check engine light on??

Rumelflowers

No there's no light on the all go off

Rumelflowers

I've just realised after you saying about the engine light just checked and doesn't even light up when you turn the key so thinking that maybe it's been takin out

yourbenztech

That was my next question... No worries, can you put your hands on an obd|| (on board diagnosis)

yourbenztech

Before you try anything it is important to correctly diagnose the source for the problem, a quick reading of codes can give us a general direction..

Rumelflowers

I'm going to get someone to come to my house today with a diagnostic computer and hopefully give the codes I need .

yourbenztech

From going briefly through what you wrote it can be many different things, the last thing you want to do is start buying new parts and making assumptions, a good mechanic is not the one who knows how to replace a part rather than the one who knows which part to replace.
Get the codes and I believe you may get more than one, don't panic and next time you buy a car pay the fee to have it checked, it will save a lot of frustration.

Rumelflowers

Good advise. I will had the diagnostic done and it came up that it is the crank sensor so off to buy one tomarrow .