So my engine won't start

[cello2119]

Alright so a few day ago my 85 318i wouldn't idle so I adjusted the AFM a few clicks, adjusted the idle and the timing. It was driving beautiful the next two days, then all of sudden when I was driving it it's cut out, the engine turns over, has fuel and spark, unplugged the afm, cleaned and regapped all the spark plugs but still no luck...

[Andy.B]

I would set the AFM back to where it was, and then check compression and fuel pressure. If they check out, search thoroughly for vacuum leaks.

[cello2119]

I would set the AFM back to where it was, and then check compression and fuel pressure. If they check out, search thoroughly for vacuum leaks.

Done everything Exocet the fuel pressure, I reckon it might be the fuel relay

[cello2119]

Except*

[hahaitzskippy]

not starting can mean a lot of issues... only way to solve this one is patience and time.

i guess you should start with your easiest checks.
1) battery voltage
2) check hoses for vacuum leaks.
3) check spark while cranking
4) check ignition coil for proper resistance between the terminals (i forgot the proper measurements but they are for sure in the bentley, also forgot in which pages. its been a while since i checked it).
5) fuel pressure
6) cylinder compression

report back once you find something as each has their own resolution

[hahaitzskippy]

Done everything Exocet the fuel pressure, I reckon it might be the fuel relay

do you hear a buzzing from the fuel relay?

[EyExR]

Do a compression test.

[cello2119]

Turns out the afm completely failed :/