R33cutting out at 7psi

[R33s2gtst]

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 

 

 

[GTSBoy]

It'll be ignition.  Plugs, or more likely, coilpacks.

[R33s2gtst]

Coilpacks are fine on idle but maybe they’re playing up under load? 

Will chuck some new plugs in this weekend and see if that helps. What gap would you recommend? I’m thinking 0.8?

[GTSBoy]

1 hour ago, R33s2gtst said:

Coilpacks are fine on idle but maybe they’re playing up under load?

That's when they do it.

There is NO reason why you should need to gap down plugs at low boost.  I run 12 psi on a Neo at 1.1mm on Splitfire coils.

[Robocop2310]

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/ 

[R33s2gtst]

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

[R33s2gtst]

5 hours ago, GTSBoy said:

That's when they do it.

There is NO reason why you should need to gap down plugs at low boost.  I run 12 psi on a Neo at 1.1mm on Splitfire coils.

I’ll try get coilpacks and plugs done this week and see how it goes 

[R33s2gtst]

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 

[Ben C34]

Boost leak. Do a pressure test

[R33s2gtst]

Have checked all piping ect but will do a pressure test tomorrow 

[Dose Pipe Sutututu]

Run stock boost, remove the tee. Does it go away? 

[R33s2gtst]

1 hour ago, Dose Pipe Sutututu said:

Run stock boost, remove the tee. Does it go away? 

Nah that’s what I’ve done and still happens 

[Dose Pipe Sutututu]

Running stock coilpacks? 

[R33s2gtst]

6 hours ago, Dose Pipe Sutututu said:

Running stock coilpacks? 

Yeah just stock coilpacks ( have 2 sets of them and they both do the same ) 

[Dose Pipe Sutututu]

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)

[niZmO_Man]

Gap the spark plugs to 0.6mm ?