strange 1jz issue

[cresslux]

Hi Guys,

i am having a very odd issue with a 1jz non vvti and im stumped.

engine is from a manual jzx90 converted into an mx83
only mods are kkr single turbo, front mount, 3" exhaust.

runs a stock ecu and fuel system (bosch 040 in tank pump to feed it)

now it was running fine and boosting properly, then one day it started breaking down under boost but didnt think anything of it as its just a thrash toy.

next time i drove it its that bad that you can barely accelerate, makes no boost and it does it free revving also (you can get toi around 3-4k rpm)
it pretty much just starts coughing and spluttering under any load at all and if you put your boot into it, it completly stops firing all together.

it starts and idles like nothing is wrong at all.

i have tried:
ecu
testing tps (by unplugging it and no difference)
coils
ignitor
map sensor
o2 sensor
new plugs (bkr6e)
fpr
tested fuel pressure

all parts that were swapped are from a known running car, and the fuel is fresh (car had been sitting for a while before the problem started)

checked for codes and there's none (except for vss because there is no speedo)

thanks guys.

[Arthur]

Sounds like limp mode. Try a simple thing next. Closely inspect ignition loom to each coil including the connectors.

[cresslux]

not limp mode as there is no codes, and limp mode sounds like a rev limiter.

it also has fairly new coil connectors and i have chaged the coils for known good ones.

i can free rev it slowly almost to red line, but if i stab it, it dies. it really seems like a fuel issue so im going to chage the fuel dampener.
the engine is about to be removed to be put a propper track car so i want to get it running properly first (even though the whole fuel system and ecu is going to be aftermarket when that happens)

[oldcorollas]

does sound like fuel, but if you have fuel pressure..
stock FPR?
injectors ok?
return line blocked? tank vent blocked?

[dnegative]

Mine did weird arse things when the coolant temp sensor died

[cresslux]

turns out it was the fuel pump.

under no load it flowed fine (free flowing with the feed line undone from engine) but as soon as you loaded it up it would die in the ass.

thanks guys.