losing power under acceleration

[Turboz280467]

can someone glance at my tune please. gen 3 4.8 stock bottom end, gt45 turbo. Was base tuned by a reputable tuner in the area. idles good, AFR looks good. while trying to get data logs car is losing power under load. can hear the turbo spooling up, but theres no pull. let me know your thoughts.

[reubone]

You sir have a serious leak somewhere. Your fuel trims are way out of balance and there is no boost being registered at all. I would look for a pushed intake gasket or something

[blindsquirrel]

What injectors, what MAP sensor, what type fuel system (returnless or referenced) and what base fuel pressure? Is MAF removed permanently or just failed in the tune?

[Turboz280467]

ok, thank you. i will check that out immediately.

[blindsquirrel]

You can't use the SAE generic MAP channel, must use the specific 2-bar MAP in the scanner. The SAE one will not read anything over 105kPa.

[Turboz280467]

deka 80lb, 2 bar gm map sensor, running 55lb of fuel through my regulated return style regulator. maf has been removed but i believe the tuner set it to fail.

[blindsquirrel]

Deka 80's are like 94lb-hr at GM fuel pressures.

Your file has the injector data set up with the flow rate & offset tables sloped, as if it were still a returnless system with no vacuum/boost reference.

If '2 bar gm map sensor' is a less helpful way of saying 12615136, or the Cobalt SS BARO sensor, then the linear/offset should be 200/8, not 200/10. 200/10 is simply the default values that get auto-populated when the 2-bar OS is applied. They should have been adjusted to match the actual sensor being used.