7m stalls/stutters with boost

[Mr dude]

As in the title, my 7m stutters with boost.
I have done the lexriemer upgrade, with afpr and have a ugraded ct26 with a 50 trim. After doing this mod the car ran perfect @ 18 psi, but now it starts to stutter when the boost comes in (@ approx 4,5K) I also have the AVCR, and when I turn the boost off, the car runs perfect without any stutter.
I checked everything like the AFM, injectors, ignition, sparkplugs, turbo etc. but nothing works. The car is also running pig rich, wich I can read on my wideband. Upgrading/downgrading the fuelpressure doesn't seem to help a thing, It keeps running rich. Does anyone have an idea of what this might be?

Thanks

 

[jetjock]

Rich when? Part throttle or boost? And how rich? At what boost level does the stutter begin? Around 3 psi?

 

[Mr dude]

rich @ wot, like 10 AFR. It doesnt help a thing when I decrease fuel pressure. And it starts to stutter when the turbo really starts to make power, so with wot around 4,5 K. With the boostcontroller off it stops, but I still read boost like 13 psi. (maybe wastegate problem, but thats not an issue)
When it stutters, I read very high AFR spikes like 18 to 19, when the overall AFR is 10 @ wot. I checked the intercooler pipes etc. but there is no leak whatsoever.

To me, it sounds like a fuel problem or ignition problem, but I double checked everything... And the weird thing is that it only stutters with boost, like shooting an uzi.

 

[jetjock]

You need a better way to tune fuel at WOT. Adjusting pressure isn't a good way to do it. How's the mixture otherwise? Is the engine in closed loop at other times?

As for the stutter any codes? Have you done the 12 volt fuel pump mod? If not try jumping B+ and FP in the diag block and see if the problem goes away...

 

[Mr dude]

AFR @ idle is 14.7
But right after the lexriemer mod, it ran perfect for a 100 miles or something. After that it startet to stutter more and more.
I've done the 12V mod and upgraded the fuel pump for a walbro. Before the stutter began I could adjust the AFR quite well with the fuel pressure only.

 

[shaeff]

Just out of curiousity, did you drill the j-tube, or bypass it?

 

[Mr dude]

I bypassed the j-tube but didn't remove it. Ow and the only fault code was nr 24. Something with the AFM, wich I replaced/

 

[shaeff]

OK, good. Have you cleared the codes? Many codes are stored, (though, I'm not sure which ones are/aren't), so if you never cleared them, the code you have now could just be from before.

 

[Mr dude]

This could be an old code, because I allready replaced the AFM electronics, and that doesn't solve anything...

But what could damage after running 18 psi for a while? Like injectors, or afpr.
btw I allready replaced my aeromotive afpr for a new one.