1986 BMW 318i;Turns over but engine wont run.I'm

Have you checked for voltage to the injectors? If all of them are not working it could be something as simple as a blown fuse or a faulty relay. Try this website as there were some updates done to some 3 Series models around 2007.

fuse-box.info/bmw/bmw-3-series-e90-e91-e92-e93-2005-2013-fuses-and-relay

Ignition firing order is 1-3-4-2.

have you measured the voltage @ the fuel pump or are assuming it has no power because it's not turning on? with that age of vehicle it could be corrosion of the electrical connectors. You really need to measure the voltage at the fuel pump to ensure no power is getting to it. If it has power, then likely the fuel pump sender unit (replace entire mechanism), if no power, then likely corrosion of the connectors.

you low on rad fluid? Most common reason.

check fuel pressure

the plug into the pump cud be corroded--pull and clean--chec fuses--pump may need replacin--must hav about 35psi--

Check a few things, check your spark plugs, spark plug wires, also check your fuel filter, fuel pump, but the first thing that you should check is the ground wire from your battery to the engine block

You will need to check for fuel pressure or dirty filter. If you do not have fuel pressure; be sure to check fuses or any relay pertaining to fuel pump (if electric). If fuses and relays are good check or replace fuel filter. If the fuel pump is mechanical disregard fuses & relays and check or replace fuel filter. If this does not resolve the problem then the problem could be the fuel pump if mechanical, If its an electric fuel pump it could be a fuel pressure regulator, fuel pump, crimped fuel line or other wiring issue.

These are the most common things I run across, oh, a crimped fuel line can cause the problem in either case electric or mechanical. Hope this helps in some way, been awhile sense I worked with an older car.

try and run compression tests on the cylinders..other than that its really hard to say if you have got air, fuel and spark..it should work

Does it crank when you try to start it?
Does it even makes the effort to hump a little and the goes off again?
Probably a good tune-up and a new gas pump and fuel filter and you should be good to go.