I will be taking my car back to Jamie this school holidays to check my warm start problem. That was happening prior to the previous problems (which are now fixed), so that one was just left alone until the other things were ironed out first. Your stalling problem sounds much worse than mine. Mine only happens on warm start. If I stop somewhere and start it up after 10-20 minutes of sitting, idle will hunt and it will stall while pottering around a car park, reversing, etc.

And yes, bigger injectors. 1000cc which some will say is too big but put them in, in the hope of e85 becoming more widely available.

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[I]trolololol[/I]

Ahk cool,

Mines weird. I may have made out like it happens every single set of lights, but that's not true. Def only happens when at full operating temp after maybe a 20 minute warm up drive and I would guess maybe 10% of the time? No starting issues though and it didn't do it once yesterday...

Pulling into park whilst putting extra load on the motor from steering makes it more prominent.

I'm positive it can be corrected by TMS though as the issue was non-existent prior to the new motor and tune combo. S-technic did report back to me a few weeks prior to me receiving the car that the injectors were causing a few issues so whether it just needs some more time spent on it or some minor tweaks who knows. But I'm not crying rivers about it. It out performs the fk out of the last setup running significantly lower boost.

Without having heaps of seat time I can't blame any of the shops involved. It took me close to a month to establish something was a little off

could also be the fuel pump voltage control module playing up, just a thought

i've had similar problems with fluctuating idle and stalling. generally happened once engine was heatsoaked.

air/fuel ratio at idle became to lean which makes the engine fluctuate, the air idle control valve would try to catch rpm but just made fluctuation worse.

richer air/fuel ratio at idle is what helped me with this problem.

I have 1000cc ID injectors 2.1L engine and when running 98 unlead fuel at idle. operating tempertures. Injector pulse width is around 1ms and air/fuel ratio around 14-1. Also autronics ecu is in open loop.

ID 1000cc injectors minimum pulse width is 1ms. anything below the injector becomes unstabe or goes off its linear scale.

i also can get lean air/fuel ratio at start up if engine its really heatsoaked. Fuel lines,rails and injectors are all hot.

using post start enrichment in the ecu can help. So warm start up will be rich air/fuel ratio for short period of time and hopefully the cooler fuel from the tank would of pumped into injectors by then.

Curious as to what fuel pump/pickup you guys are both running?

Some flatbrim moron had violated my gc8 prior to me picking it up and it had issues very similar to what was described above.

I always start at the beginning with problems like these, in this case that's the fuel pump. Said flatbrim had said he had upgraded it.. We will see about that. As soon as I pulled it I was 95% confident that I'd found the problem. Aftermarket fuel pump pickup, a huge no no on wrx's.

Sourced a gd sti replacement pump and assembly, no more hunting, no more surge and no more missfires. This thing would surge on mountain runs with over 3/4 of a tank.

Bottom line, if you upgrade pump keep the factory pickup.

Old pump left, sti item on the right.

Attached Thumbnails

 

O2 sensors ?

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Legacy L EJ201 MT5 MY2001