aeb28

I am having issues with my MB. Car was running without any issues (aside from an intermittent coil issue causing rough idle) until yesterday. Platform is 07 SL6 amg, v12 5.5 Biturbo.

Current issue: Car dies a couple seconds after turning over. The first time it tried to start it, the motor would not even turn over. Each time after that car turns over then immediately dies. Pressing accelerator does not change anything. The couple seconds the engine does turn over, engine runs smooth. No warning lights light up, no error message comes up on the console aside from the routine "service B" a few hundred miles away.

Began yesterday. Two days before, the car ran without issue and it is driven a couple times per week.

The intermittent/rough idle coil issue began a couple months ago and I doubt it is related. It only occurs occasionally after the car has been running a while when the outside air temp is very hot and can be solved by shutting the car off then starting it again. Check engine light comes on then turns off again after a while. I have been putting off taking it in until I can take it to a reputable dealership/mechanic, as there aren't any in my immediate area.

Anyway, my experience is pointing me towards a fuel issue however I am not an MB expert. I wanted to get some input before I start ordering parts to troubleshoot. I have done some reading and found members who have had similar issues that turned out to be slide idle position sensors, crank position sensors, fuel pump actuators, etc etc. but most aren't experiencing the exact same symptoms. Any input/advice would be much appreciated.

biker349

had this on 2004 cl600, turned out to be the accelerator and i believe it's called ignition transformer on top of engine. transformer had an intermittent short.

aeb28

Biker, was it the starter issue or the intermittent idle issue you experienced that was caused by the ignition coil short/accelerator? How was the issue resolved, did the transformer need to be replaced completely?

biker349

intermittent idle issue and the accelerator and and transformer were replaced. get it checked out with a code reader. the accelerator showed up as a fault, but the transformer had to be diagnosed by the tech.

aeb28

Thanks for the info. Is it even possible for the motor to turn over at all if the transformer completely crapped the bed? I am trying to figure out what needs to be replaced without throwing lots of new parts at it.

mohd.awaly

Best thing to do is pluging a code reader and obtaining those fault codes .. and we can build from there ..

If its a fuel pump or fuel related issue the engine dies just like you ran out of gas ( rough running untill the engine turns off ) ...

However if its suddenly turning off then its most probably a bad crank position sensor ...

Now the other thing is that both these faults would not cause the engine to stop cranking , if the engine isnt turning at all it might be a bad starter ... if its cranking but not starting or seems its going to start but doesnt im 99% sure its the crank sensor ( common MB issue )

However Dont order any parts before obtaining the fault codes . These codes will point u the right way .. gd luck

aeb28

I finally got around to pulling the codes. I am getting a P0300 (cylinder/s misfire) along with P0301-11 (specific cylinders)

No problems with starter, and I doubt it is a fuel issue. Still the same problem previously stated.

When the car is completely cold, the first time you try to start the engine it does not turn over. The starter just turns about 5-7 seconds and gives up. Each attempt following the first, the engine turns over for about 2-3 seconds and suddenly dies.

Are those codes any positive indication to what the problem is most likely? Owners with similar problems have indicated ignition coils (about $3300 fix)

mohd.awaly

Ok.. so when its on does run rough ??? Anyways man i think you should go for some new spark plugs, its plugs last for 100 000 kms ... if your close to that and ur plugs are still the original ones u should change them ...

Might be a bad coil too .. you should clear those fault codes and check it again after a drive cycle in order to pinpoint the exact faulty cylinder/s ... could be a bad coil . Bad plugs . Clogged fuel injector ....

biker349

my guess would be the ignition module.

aeb28

Thank you for your replies. Cleared fault codes, still getting the same thing.

Ended up having it towed to dealership. I just spoke with them, I pretended like I didn't know anything about it to see what their input would be. They said they couldn't find anything wrong with it other than it wont start, and they want to start with the fuel pressure sensor.

I would think a faulty fuel pressure sensor would have thrown a code. According to them they aren't seeing any codes They said at $600 for parts and labor it would be the cheapest place to start and the most likely, but that doesn't seem right from what I have read thus far, what do you guys think?

hillcreative

You shouldn't have cleared the codes

aeb28

That's helpful.

I have all of the codes noted before I cleared them. I can't see if they re-occur with an OBDII without clearing them first.

Going go start with the fuel system after all, Fuel pressure is 0 bar. Diagnostic reads fuel pump is good. Disconnecting the fuel pressure sensor puts fuel pressure at 8 bar. Hopefully a new fuel pressure sensor will fix it.

Apparently the fuel pressure sensor talks to the the sending unit/pump directly, therefore if malfunctions while the fuel pump doesn't no codes come up.