I know this question has been asked before, but most of the answers have lots of technical stuff, which just isn't me. I have a 93 wrx sti ver1 which was fine up until this morning. Now when i accelerate the rev needle just swings round and no boost comes on. I have a boost guage fitted which shows negative at standstill and only reaches 0 at acceleration. It will go above this if i suddenly drop a gear but then drops to no boost again wehn i change up. Any help please.

Sounds like the ECU has gone into 'limp home' mode meaning it has detected a fault and therefore employed safety measures. Look HERE for instructions how to diagnose the fault. The info on the 'link' also gives information on how to reset the ECU. ;)


Cheers

A similar thing happened to my MY99 turbo, turned out that the wastegate actuator arm had come adrift. If you shine a torch under the heat shield you should be able to see whether or not it's attached. AFAIK the limp home mode allows 0.5bar boost or something. Hope this helps.

Check all your inlet hoses!