Here is my setup:

RX6B Kit running 1 bar of boost
Midpipe
GT Spec exhaust
1200/850 injectors
250 walbro pump
sx fpr
PFC tuned by XS Engineering
XS powerpack ignition
b10egv plugs (new so it's not the plugs)

When i drive the car, after it is warmed up, whenever i rev past 10lbs (right when the wastegate is supposed to open up), it stutters and will not rev higher, but it is all fine if i keep the boost under 10lbs. Then all of a sudden it will fix itself a little later and work 100% perfectly and act normal above 10lbs of boost

It is also very odd, when it is doing the stuttering over 10lbs, if i idle it at that time, the idle is more rough. When it finally starts acting normal over 10lbs a little later, the idle is PERFECT?!?!

It is extremely frusterating, anyone can shed some light?

Thank you,

Ravi

 

One possiblility may be the mixture is way too rich at 10PSI and over. Its limiting the reves to go up with its over-rich air fuel ratio, or super retarded timing. When you bring the car back to idle, the excess fuel is still not completed exhaust from the engine, or the plugs, thats why it idles rough for a little while.

 

^^^ EXACTLY! i had the same thing happen to me with the stock twins and a powerfc. only diff is that as soon as i got on the boost the car would stutter and not rev... turns out the ecu was dumping too much fuel. when this happens to you look out the back and see if theres a ton of black smoke... if so then thats your prob

 

Mine has no black smoke, but seems to be running pretty rich....

 

There is also possibility when you are running a very rich mixture, and your iginition system cannot ignite the mixture. If you don't feel comfortable taking out fuel by yourself, you might want to try to install a ignition amplifier.

 

already have the XS power pack ignition amp. Any more ideas?

 

Still happening, only weird thing is it is fully intermittent, sometimes it will boost perfect, sometimes it will stutter and not let me rev, this is getting very frusterating.

 

try spark plug wires, if not then bring it back to XS and have them look into it

 

DID it happend when you got tune AFTER XS? you will need wide band to dig the probelem and your commander to monitate stuff.