BMW Repair: PLEASE HELP, fuel pressure gauge, fly wheel

Question
I just bought a 1985 BMW 735i, the guy i got it from said it
ran and just needed a battery so i bought a battery and like
a retard i didnt look at the way the old battery was hooked
up and i hooked the new one up backwards now my car wont
start i have fire going into the coil but none coming out
and all the car will do is turn over i've checked all the
fuses and relays they are all good. When i hooked the
battery up backwards the ground from the alternator burnt
off so i replaced the end on it and regrounded it to the
chasis, but the car still will not start, any ideas?

Answer
You said you have power at the coil,which is good.Have you put a fuel pressure gauge on and checked that yet.And have you checked for spark at the plus?Hooking up a battery backwards isn't a good thing to do.You replaced the ground wired from the alternator,I do belive it was on the block,that should where it was if you moved the location.There is a relay on the firewall passenger side,it often fails in older cars(which this is)clean connections in the connecters are important also with age they tend to turn green internally,so you may need to replace wires if the casing is green and bumpy.
They also use sensors in the bell housing to make spark(the reference sensor has a grey tie on it)make sure the pin is still in the fly wheel,you can check that if you remove the sensor and turn the motor over by hand.