2008 E90 M3 - No Start Issue

[AquilaBMW]

Hi Everyone -

I am scratching my head over an issue with this car. It's a 2008 M3 with 94K miles on it.

The car broke down recently and it was towed to the nearest dealer. The diagnosis was a dead fuel pump. $2K later, the fuel pump was replaced.

On the day the car was to be picked up, it would not start. The dealer then apparently performed a compression test (not sure why), and they have now come back with a diagnosis of a Camshaft error.

Then it gets weirder - they now say the Camshaft error had led to a clutch and flywheel replacement for $4K !!!!! I cannot for the life of me figure out how they went from fuel pump to dead car to camshaft error that supposedly led to the car needed a clutch and flywheel.

Any body have any ideas at all? The car is about to be removed from the dealer. There are serious doubts about their competency.

[deansbimmer]

There are literally thousands of possibilities...

Was the engine recently replaced?

What does "broke down" mean? Were you driving along at road speed and it suddenly died?

Details details details!

[///M Power-Belgium]

That's a strange situation and it sounds not good ...
How long and how many miles you drove with this car ?

[AquilaBMW]

I got the car yesterday and had a chance to quickly check it out and also whatever the dealer had done to it.

The work sheet shows they replaced the EKPS and fuel pump and had to do some programming. There is no mention of any codes, etc. The work sheets then "recommends" replacing a faulty flywheel and suggested clutch as well. How they know the flywheel is bad is beyond me since the car was not running when it got there.

Supposedly, after they replaced the fuel pump, the car started running rough which it had never done before. They then decided to do a compression check - like what ????

Anyway, compression check supposedly resulted in the engine getting a clean bill of health and everything was okay. However, when the car was supposed to be picked up from the dealer, it would no longer start. Then dealer claims it was due to potential faulty flywheel or sensor.

Here is a kicker.... the car gets to my place and as soon as we get it off the AAA flat bed, damn thing starts up. Car fires up, but runs / idles rough. So I shut it down and planned on working on it later.

About a couple of hours later, I try to start the car and it turns over very weakly. At least it turns over, but it won't fire. Classic symptoms of a dead or weak battery.

I go check the battery voltage and sure enough, it shows 11.6V. My experience is that anything below 12V will not start up a typical BMW V8. The battery probably also has low amperage at this point.

Could this be the source of all the issues? What's the best way to remove the battery on this car? Well remove and replace?

[AquilaBMW]

So.... finally had time to work on the car. Installed new battery and synched it to the car. I scanned the car and as expecting, got a ton of error codes, included one that kept coming up - Please Tighten Gas Cap. Not sure why that kept coming up.

Anyway - cleared the code and ran the car again to see what was left. Lo and Behold, the one code that would not go away was the CRANK SENSOR ERROR code. I replaced the Crank Sensor with a BMW Original part. The car still barely starts and barely runs. It sputters at start up and will barely run, it basically dies once you release the clutch. When you get it running, you can drive it and it shifts very well and very smoothly, no issues until you have to come to a stop like in traffic. Usually, it just dies, but occasionally, it will idle in traffic.

It runs really rich and seems to misfire a lot - however the only code so far is that Crank Sensor code. Any ideas would be most welcome.

[deansbimmer]

I asked before but you didn't answer... Has the engine been out of the car?

This sounds very similar to an M3 I helped a customer with who had a shop replace the engine due to RB failure. The shop didn't route the engine harness correctly and the wires that lead down the back of the engine contacted the headers and melted. Symptoms almost exactly like yours.

[AquilaBMW]

Originally Posted by deansbimmer

I asked before but you didn't answer... Has the engine been out of the car?

This sounds very similar to an M3 I helped a customer with who had a shop replace the engine due to RB failure. The shop didn't route the engine harness correctly and the wires that lead down the back of the engine contacted the headers and melted. Symptoms almost exactly like yours.

As far as we know, the engine was never removed. However, the dealer did supposedly do a compression check on the engine. Could they have misconnected some wires?