1999 Chevy 2500
6.0 with 317's
BTR stg1 cam
decaped injectors. I tested and flowed them on a real bench. 58 psi they flowed between 662 and 665 cc's. Converted to pounds at 6#s for a gallon of fuel my math is 65 pounds an hour.
I'm running a return style boost ref'd fuel system.
The pump is a demon 525 pump.
I'm running a 2 bar OS but am using a 3 bar sensor. I did this to get a bit more granularity and I don't anticipate running more then 14-ish pounds anyway.
Turbo is a 78-75 with a 3-4 psi spring in the gate untill I sort this out.
I am running strait open loop SD. (or at least I'm trying to)
The log and the tune are attached.
The problem is the truck will tip into boost and be pretty rich and then suddenly go dead lean to the point the KR goes crazy and it will actually pop out the intake.
In the log its around 2.01.862
I do not have the ability to log the afr unfortunately but the wideband on the dyno pegs super quick.
I have ran a fuel flow test. Hot wire the pump and run the return into a 5 gallon jug. With only batt voltage of around 12 it fills a 5 gallon jug in just over 30 seconds. This is in line with the 525 pump info I can find and certainly good enough for the 125 kpa I'm running into the problem at. That also eliminates the fuel bucket starving as well.
I pulled the injectors and re-flowed them as a sanity check and the results are the same.
I've been over the tune a bunch and can't find anything for sure. Is there anything you guys see I did wrong? I have done a few of these and never had an issue like this before.
Thanx guys.