Need some opinions on tracing problem. Breaks up when in boost

[sy445]

Trying to tune my truck and I have a somewhat unsmooth acceleration when in boost. Truck drives great all the time til I get some real cyl pressure from boost, i only run up to 15lbs on 93. It doesnt really seem like detonation, its really faint and Datamaster doesnt show much of anything for knock so Im looking for some opinions.

What Ive checked:
plugs are ngk ur6 gapped .028 look good
cap, rotor, wires, coil all msd checked and seem good
Afr according to plx wideband & datamaster is in the 11.5-11.7 range when in boost

I have a very small exhaust leak at the atr header/turbo flange (cant hear it but i can barley feel it at idle with hand)
Im curious if this could be affecting my problem??
I tried to search threads on pre turbo exhaust leaks and couldnt find much info.

Any help greatly appreciated

 

[Trapper]

Re: Need some opinions on tracing problem. Breaks up when in boost

Can you post your data master results?

 

[sy445]

Re: Need some opinions on tracing problem. Breaks up when in boost

Nolan is tuning and it doesnt seem to be in the tune. Any ideas other than tuning which might cause this?

 

[It's just a six]

Re: Need some opinions on tracing problem. Breaks up when in boost

Might try closeing your spark plug gap just for the heck of it ,check your plug wires. check your ohms.
Look under your hood in the dark (engine running) for glowing plug wires or possible grounding areas.

 

[sy445]

Re: Need some opinions on tracing problem. Breaks up when in boost

gap is .028 and has been. never gave me a prob til all of the sudden. checked wires and looked in dark and nothing seemed wrong??
truck drives perfect until under load, i dont get it?

Anyone know what happens to a truck in boost with a large exhaust leak before the turbo?

 

[pinellas50]

Re: Need some opinions on tracing problem. Breaks up when in boost

I'm chasing a similar issue myself. Here is my post.

http://www.syty.net/forums/showthread.php?t=59685

I don't know if that will help you or not. I haven't solved my issue yet but there might be some ideas for you in my post.

 

[Quatro]

Re: Need some opinions on tracing problem. Breaks up when in boost

I had similar problem, only worse. ran perfect except under boost. Fuel pump cured it.

 

[10secTy]

Re: Need some opinions on tracing problem. Breaks up when in boost

Change out the plugs for a set of UR6IX gaped at 0.028. If these do not cure it you have other issues.

Nolan