HELP! RB25DET S2 stalling under load

[NZSil80]

hoping for a lil bit of help here, i have a s2 rb25det in a s13, ffp top mount turbo, fmic, 80mm throttle body, straight through 3" exhaust, walbro 500hp fuel pump.

so it idles and free revs fine, but as soon as i try to drive, it starts missing and then stalls. Have checked the timing, u=at idle the timing marks on the pulley are way out, i have to turn the cas hard right for it to be on 15 degrees, and even when its there it still stalls as soon as it comes under any load. Have manually checked the timing belt marks, at TDC everything is bang on perfect. I cant figure this out. Is running on a standy ECU, any help would be much appreciated. Thankyou in advance

[Yellow4g63]

check for a boost leak. pressure test your intercooler piping look for lose vacuum hoses.

[NZSil80]

All done. All ok. Would a faulty cas do this??

[Yellow4g63]

Did you take the covers off and try and set the timing (mechanical)? sounds like it's off by a tooth probably. If it isn't then maybe the CAS. It should throw a code tho but wouldn't hurt to switch it with one that works.

[NZSil80]

Yeah everythings spot on mate. Have checked multiple times ot was my initial thought that it was a tooth out. Have a wprking cas to try tonight

[NZSil80]

Just tryd a working cas. No difference at all. Cas centered reads 35 ta 40 degrees. Its got me stumped. Any other auggestions would be much appreciated

[Yellow4g63]

Is the Rb pulley one piece design or 2? Could be a bad pulley, I have seen this happen to VVL pulley.

[NZSil80]

Fairly certain its a one piece. Even if it was the pulley this n wouldnt cause thw stalling underload etc