I'm attempting to help a friend of mine get his new 5.3 build running but we are chasing our tails trying to figure out why it's so rich. It's just the engine sitting on a 68 Camaro subframe. We have already tried all of the basic troubleshooting, and initial tune setup steps for a larger cam, and while some of this helped, this thing is still pouring way too much fuel.
It is a 2000 5.3 out of a tahoe, changed to DBC from DBW that it was in the tahoe. The heads are ported stockers, the intake is an open plenum aluminum(not sure of the brand) with a 102mm throttle body(probably too large?). The cam is a Howards 226in 234ex .525 lift with a 109 LSA. Stock injectors.
I have bumped up the idle RPM/airflow settings. I have advanced the timing down low. Also, I've subtracted nearly 30% off of the VE table in the idle/low RPM areas, which seems like too much to me, but it still isn't making enough of a difference.
Compression reading around 180psi all cylinders. We have smoked the intake looking for leaks(none found). Fuel pressure reading steady 60psi. We pulled the intake with injectors, cranked the engine and looked for any leaking injector(none found). Checked grounds to PCM and all sensors, all seemed to be good. And a lot of other checks I'm sure I'm forgetting.
It does run, and has a rough idle. After running a while, it will foul the plugs and when you shut it off there will be fuel puddling in the intake ports. Weirdly it also will have oil in the intake, but the only place this could come from is the rings getting washed out from all the fuel(PCV is NOT connected)? Or bad valve seals, but all that is brand new.
Anyways, I'm getting stumped, maybe there is something in the tune I'm not catching(new to tuning). Hopefully some of you might have some ideas? Any and all help is appreciated.