My 1995 bmw 318is wont start with the key. the dash lights come on battery is good, but it wont crank. it will start if i pop the clutch. but jump starting doesnt help.

Make sure battery has a full charge and battery connections all good. How long since a tune-up?
Have a helper crank it while you check for spark at the spark plugs. If spark everywhere, use a gage and check proper fuel pressure. Also check for fuel injector pulse.

starter solenoid or starter relay

no crank?
here they are.
http://www.fixkick.com/nocrank.html

battery dead
battery lugs corroded.
fuse blown.
is the CHECK engine lamp glowing> key on?
are all dash idiot lamps glowing key on , showing 12vdc power is good?
or are they dim>?
is car a A'T or M/T auto or stick?
if auto, wiggle the gear shifter, cranking,
if Stick wiggle the clutch, cranking.
got a volt meter?. is battery at 12.6v ?

if battery is good, hot wire the solenoid
crank now? yes, then key line is dead.
if not, the starter,battery or cables are bad.

try jump starting it. if that works the battery was
1; bad.
2; not charged, and ALTenator system is bad. note i said system.

post is good and clear, no engine size stated.>>>
can you jump start it?//
this simple check proves battery is good /bad or just discharged.
yes, jumps and runs. (ever clean the battery lugs ever?
if it jumps the battery is bad/or disharged, so charge it.
no, wont jump cold
bad starter. or funky key line.

1: i hot wire these starters,
cranks ok, good starter.
no crank bad key line
if key line is dead, well wiggle the key and wiggle the gear shifter.
is car a A/T or M/T.
if M/T wiggle the clutch.
now you have your answer, an why. how is a differnt horse.

The first thing to do would be to check all fuses. Sometimes a very random blown fuse can cause this. Also unhook the battery for one hour to reset all systems, and try a jump start if you have not just to be sure it isn't a battery issue. Also try locking/unlocking the key driver's door a few times using the key in the door. If the fuses are good and the battery reset does not help, nor a jump or key in the door, then there are a few other things that can cause this such as bad key - try another one, bad brake light switch, the switch is above the brake pedal, shifter not fully in park (auto transmission only) - try moving it around a bit, bad transmission position switch, bad clutch switch, dead starter/solenoid/relay or bad ignition switch/cylinder/start button.

ill answer for NO ELECTRICAL POWER :
sure and is easy with any DMM meter, got one? any $20 DMM.
my guess;1
engine will not crank
dash lamps out.
head lights out. dead.
post systems of electrical system , all parts that work and those that dont work, and problem is easy.
cleaned battery terminals.
tried borrowed battery that reads, 12.6vdc ? (charged is 12.6)
2012 that is in warranty car.... ?
my guess on 2012
jumping a car, that is battery jump starting.
a battery can short, and no jump start on earth will start shorted battery in car. but does lay down some big sparks, or burns up cheap walmart cables.
if the car will not crank, say just that, my starter motor will not crank
jump started from live running other car.
if true then make sure headlights work , if they dont work fix that first.
HL must always work, even keys in pocket.
best is to put a fully charged battery in the car, jump starting can cause
surges that can damage sensitive electronic$$$, do jumps as a desperate measure,
with a charged battery,
1: Head lights work, no fix that , use voltmeter
2: cranks robustly.
no , wiggle shifter lever, (on A/T cars the park switch blocks cranking) On M/T the clutch blocks cranking.
with any dMM
measure battery voltage before crank and during.
12.6v good. reseted.
cranking.
0 to 10v bad (weak battery or shorted starter motor)
11 and above good. and must crank, if not , starter is bad.
to prove starter is bad, check voltage at starter solenoid coil wire lug.
it must be at 11v cranking , below 8v it chatters, and fails.
if at 0v cranking this lug that means the Key start line is failing.
A/T switch not closes, or bad ignition switch.

If the headlights and dashboard lights are working but the vehicle still does not start, the ignition switch is most likely the problem. or a bad wire from switch. If your battery checks out, but the starter is still silent, it may be a faulty ignition switch. Turn the key to the on position (not all the way to start). If the red warning lights on your dash don't light up (and your battery connections are clean), the ignition switch is bad. If they do light up, turn the key to the start position. The dash warning lights should turn off at this key position (most cars). If you're not sure, turn on the headlights. When you try to start the car, the lights should either dim (a lot) or turn off completely. If they do, your ignition switch should be ok. If not, the switch will need replacement. check the wires to starter and see if you have power when car is switched on, do this first! good-day! if it cranks but does not start. check to see if spark and fuel, and check all fuses also.

you have to figure out where there is a short in your wiring--follow wires, look for broken, missing insulation--if it started in lights, look there first maybe. Also check the connections of plugs. Good luck it may take some searching.

Disconnect the negative battery terminal, using a 12v test light put one end on the battery terminal put the other end on the cable if you have a draw the light will light up, go threw and disconect one fuse at a time until the light goes out, notice the fuse you pull out when the light goes out that the circuit that you have your short or draw in good luck

how old is your battery? sounds like not enough juice from the battery to crank the starter motor. next time it happens, have someone jump you (or use a battery jumping box) to see if it will now crank. if it does, then battery is too old and should be replaced. good luck