[jwizzle]

So I have a 180SX with a blacktop straight cam. The other day it cut out completely whilst the throttle was wide open and would not start again after. I have spent days on it and tested the following, but still won't start, just cranks with no sign of firing:

- Probed ECU pins with multimeter and oscilloscope to check it has power, is sending injector pulses, etc (which all seems to be working as it should).

- Compression, all good on all 4 cylinders

- Ignition, a strong spark on all 4 plugs

- Fuel, tested fuel pressure ~40psi and also pulled the injector rail out and tested them. All 4 spray in batch mode whilst cranking

- disconnected MAF, still no start

- Pulled fuel pump fuse, this is the only thing that makes it cough and try to start. When pulled out, after a few cranks it splutters and seems like it wants to start, but doesn't (very strange). But then when the fuse is put back in, back to cranking with no sign of starting.

- Have even tried easy start sprayed into the throttle body with no sign of starting

Please could someone offer something that would cause this issue, as I am tearing my hair out! The only thing I haven't tested is timing, now if the chain had skipped a few teeth, you'd surely expect a backfire though? not just cranking without anything? If it had slipped any more then you'd expect no compression?

Thanks in advance