need a bit of help

runs fine under normal conditions
but on full throttle have teribble miss fire
let of the throttle a touch black smoke then its of
changed leads plugs dizzy cap arm
had turbo problem put a nother one on since then i have had this missing
smells like it is running slightly rich as i am taken her to spec one over the weekend any surgestions would be great will leave it with you all
many thanks in advance

 

sounds like mine 2! some one else said get it set up im gona phone up sitech today c wen hes able ta do it

 

You sure its not overboosting and the chip is cutting it out, thats why when you back off you get all the black smoke of un-burnt fuel.

 

how would i check for over boosting
as it is running 10psi according to my gauge
and i have no bleed valve on

 

Have you checked the timing? Sounds like its running rich!

Not a mechanic but had similar problems and it was timing. Would it be possibly an injector. Maybe dumping too much fuel. Maybe someone else can advise on that.

 

Is it chipped??

If not then thats why it's missing. When you hit 10psi the boost will be cut buy the ECU if it's not chipped.

 

timing is bang on
its not chipped
was running this al day long before turbo went
put sierra cossy turbo on ever since had miss fire on full throttle
running slightly rich but nothing major
coould it be a problem with the air /fuel mix through air mass ?

 

If it's not chipped and you hit 10psi the ECU will cut the ignition. Try turning the boost down and see what happends

 

As above a standard ecu wont have anymore than that till it cuts the ignition.