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I have a r33 gtst ( auto ) and it’s stock apart from a front mount intercooler, carback exhaust and pod filter. 

It runs fine up until 6psi but once it goes over 6psi the car cuts out and jolts foward ect . Can’t figure out if it’s a boost cut or fuel cut or why it’s happening. 

Currently running 7psi with a manual boost tee 

Any ideas what it could be? Have checked the afm and it seems fine, vacuum lines are fine and can’t find any boost leaks ( it holds boost as long as it’s less than 6psi ) 

im thinking it might be coilpacks, spark plugs or tps but don’t really want to start buying parts until I know what I need so I don’t replace stuff that isn’t broken 

 

 

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How high in the rev rang do you hit 6psi before this happens?

Do you have any aftermarket ECU?

Read this topic.

https://www.sau.com.au/forums/topic/336073-r33-rb25det-cutting-out-on-boost/ 

5 hours ago, Robocop2310 said:

How high in the rev rang do you hit 6psi before this happens?

Do you have any aftermarket ECU?

Read this topic.

https://www.sau.com.au/forums/topic/336073-r33-rb25det-cutting-out-on-boost/ 

The tacho doesn’t work but I’d say it’s somewhere around 4-5k revs 

stock ecu

Update: have changed spark plugs ( regapped to 0.9 ) and it seems to have stopped the boost cut but now it’s misfiring under load, changed the coilpacks too and didn’t change anything. 

Is fine if I drive really quiet but if I put my foot anymore than half way down it just sits there farting . Any ideas what could be causing it? Will have a look at the fuel pressure but I’m thinking it’s something to do with the plugs as it got worse when I changed the spark plugs 

wouldn't surprise me if both sets are cooked... Borrow set of decent coils that aren't yellow or red in colour.

If S1 check ignitor/swap it AND check the ignition harness (clean or replace or hit it with WD40)
if S2 check the ignition harness (clean or replace or hit it with WD40)

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