Weak spark - 2003 BMW 5 Series

Your engine has a separate coil for each cylinder/spark plug. Are they all weak? How did you determine the spark was weak? And is the weak spark causing a problem?
You're guessing at a cause, but haven't stated what the problem is. Post a new question and tell us what type of problem you're experiencing -- engine doesn't start/run, engine doesn't idle, poor performance, etc. Also include engine size and type in the question.

The coil makes the spark. If it's weak the coil's secondary winding is bad. Replace the coil.

this can be caused by a weak battery check battery and charging system to verify a good working system. it could also be a weak coil not being able to supply enough output voltage for the ignition system. you don`t say if its weak coming out of the coil or at the plugs. if spark is weak at the plugs it could be a bad cap/rotor, ignition wires. it could also be an ignition module problem or pick-up coil in the distributor.

This is just a shot in the dark but have you checked your ground wire from the battery to the engine/frame.A bad ground wire could be rotten on the inside and you would never know it.This would give you a bad path for current completion and therefore a weak spark.Just a thought Good luck

06 GC
v6,weak spark 3.7L V6 , WEAK ON ALL 6 SPARK PLUGS?
franco (even google cant guess this.... )
pulling sensors proves nothing.
did you use a SCAN tool yet, that be first, and do it 5seconds cranking
and see those DTC pop?
getting P03xx codes, cranking? huh? any scan tool works... rent one.
weak spark is weak battery, in most cases. on all 6 plugs.
your v6 has cops, coil (ignition) over plugs, COPS.
it has 6 COP, all 6 must work or running will be hard.
check all 6 for spark with a new test spark plug at the end. gapped right. (ground the spark shell and keep hands away)
now crank, all 6 work>? these COP are very hot. the make nice
fat blue white spark , with a charged battery.

lets run the list.
did you check all fuses in both boxes from blown(using ohm or volt meter)>>>?? 0 ohms is good, infinity is bad, some look good but are in FACT bad.
is battery charged to 12.6vdc rested???????
are the head lights full bright turned on??????
Due all dash cluster warning lamps come on , for the self test, all jeeps do, key on?? and for sure the CEL lamp?
Do you have an Immobilizer? option? on car. if yes?, does the IMMO lamp go out, before you crank, (if not it will kill spark and fuel)
for sure. see IMMO here.
http://www.fixkick.com/Jeeps/SKIM.html

now how does (ASD) really work?
the first test is to be sure the ASD relay stays closed for the full time
cranking. if it drops out in 2seconds, then that is ASD drop out.
http://www.fixkick.com/Jeeps/ASD.html

It is tricky , if the PCM sees weak spark , it will drop out.
so check spark carefully during that 2 second event (yes, painful)
yes, takes 2 persons to do this.

check spark timing, to make sure the cam chain did not fail.
ill stop here, it only takes 3 things to run.
good engine (compression and vacuum good)
good spark (all 6 COPS, and timed right)
good fueling. (lots more tests, i stop here.)

A timing chain could be put on wrong, for sure but it has ab solutely no control over spark. Weak or no spark is an ignition problem, the timing chain only controls where everything is when the spark occurs.

if the ht leads to the plugs is separate to the coil/s replace the leads
they are carbon cored and fail with super high resistance causing weak spark

cam shaft sensor

your current passing coil is weak! may be your sparking plug is weak and there is a problem in your sparking wire! your engine is ok go to any machanic shop and repair it from there! vote me if it is helpful for you!

id be leaning twords a coil pack on this one, if the spark is weak change the plugs and wires first since its cheaper, then if that doesnt cure it change the coil pack.