My car war running fine until one day it just decided "i am not going to start at all".
It cranks but no ignition, no spark. I had driven 30 miles to event and it would not start for return home.
I have tested and am more or less happy with following:
Cam sensor (single one on front right hand side). Tested resistance and also during crank using osciloscope and see the normal cam signal waveform. Is there another around back of engine for other side of cam? According to service manual there isn't.
Crank sensor (single on top of crank). Tested resistance and also during crank using osciloscope and see the normal crank signal waveform appearing.
Coilpacks. Not sure - but I know they were working fine up until this immediate failure happened. No way 4 seperate coilpacks could go at the exact same time. And there was no single one gone either as engine was running normally. Tested voltages to coils and continuity from coilpacks back to ECU. All fine.
Tested spark plugs in coils, but can see no spark. No way all four NGK Iridium spark plugs could go at once - they worked fine on same day it failed.. literally 20 minutes before.
There are NO pending codes in ECU (4 historical ones but I don't think they are relevant right now if it doesn't see them as pending)
Checked battery with battery tester and it is at 98% health and 99% charged. Can't do battery crank test as engine won't start obviously.
Checked engine grounds and they are OK.
Can hear the normal Walbro fuel pump noise when ignition is turned and it primes up.
Can also smell petrol from cylinders when I crank with fuel relay still connected.
I am able to hand turn the engine with one hand and wrench on crank pulley so engine is not seized.
The timing belt looks OK... no damage visible... i haven't taken off centre cover or crank pulley so I haven't checked full alignment, but this has run fine for years without problem. May need a normal timing belt change.
For the first 30+ times I cranked trying to diagnose this, I was getting normal sounding crank, but now I think starter has died... it started making that screeching noise like engine is running when you crank (like the starter cog not engaging with spinning flywheel), and then after will only very slowly crank, not normal sound. So I think I killed the starter and need replacement. Also when I tried to remove old starter and took out two bolts holding it, it did not fall out - it is stuck solid to the crank case... will not move... can't get it off... what could cause this?? It can't be "jammed" on flywheel... because I can turn engine easilty by hand. So on idea whats holding it on now.
Is there some other parts of an 2.0 STi engine that would cause the ECU to decide not to send the "spark" signal to coilpacks during crank? AVCS? Other block sensors I don't know about that might have failed? MAF airflow sensor? I forgot to try cleaning it but I do regularly clean it. Could a bad boost control solenoid stop ECU from sending spark signal?
It's annoying me that ECU just decides to not send spark signal to coilpacks but won't tell me why not!!
I don't want to go throwing money at replacing all sorts of random sensors... and obviously I can send to garage but now that would require a tow-truck from my house so not cheap!