[s-cars] Checking for spark

[John Cunningham]

The BMW immobilizer ("EWS") on those cars has a couple of failure modes 
and can cause no starts.  If it is turning over then the key-EWS 
validation sequence is working.  Then there's a second ECU ("DME") to 
EWS authentication that has to happen. That could have gotten out of 
sync especially if you had a low voltage issue at some point.  However 
that said... the report of gas flowing suggests that should be fine as 
the injectors would not fire, and poor running prior to the issue says 
something more fundamental is wrong.

I suggest you pull codes on it using a true BMW scanner.  When you said 
no codes I am guessing you used a generic OBD scanner, these cars will 
often store more information than a 'generic' scanner will reveal.  
Although not impossible it would be unusual for a 3-series of that 
vintage to not have any codes after running roughly let alone not 
starting.  Options range from BMW-authorized software on PC's, to 
various free 'in the wild' BMW PC software options using eBay cables, to 
pro-hardware scanners w/ BMW compatibility, to now some decent 
iPhone/Android compatible devices (look at "Carly" - requires you buy a 
hardware item and the software, total around $110 but really user 
friendly and convenient).

In the meantime, try the quick pull the plug trick on the MAF.  The MAF 
is known to go bad on those with time and can cause intermittent no 
starts, just happened with my friends 530 a few months back. Beyond that 
yes cam/crank sensors.  Because the car wasn't running well before, 
likely something significant is going wrong... other rough-running 
causes on those M54 motors are:
- CCV (i.e. PCV)
- Vac leaks - boots / intake manifold (they can crack) etc.
- Coils
- "DISA" valve
- fuel pressure / pump
- O2's

/off-topic-bimmer-talk

On 1/27/2016 2:49, tedebearp at yahoo.com wrote:
> My question was prompted my wife's E46 (BMW) 330i that won't start.  At first I thought it was the battery, but the battery passed the load test at the FLAPS and is fully charged.  The engine seems to be getting fuel, judging by the smell of fuel at the tailpipe after unsuccessful attempts to start it.
>
>

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*John J. Cunningham*
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