the only way to tune a 6.9 is pump timing, resetting the metering screw in the injector pump or putting a bigger exhaust. those 6.9s were all mechanical with no computer comtrol on the engine, even the cruise control was mechanical. hope this helps.
A forum community dedicated to Ford F-series owners and enthusiasts with a Power Stroke diesel engine. Come join the discussion about performance, bulletproofing, modifications, classifieds, troubleshooting, maintenance, and more!