Weird Shift Behavior/ Stalling
BE WARNED! THERES A LOT TO COVER HERE!
I have an older 70050 kit in a 96 K3500. Its running a rebuilt LQ4/4l80e combo. Nothing super knarly, .030 pistons, 241 heads and a sloppy stage 2 cam. Engine does have around 11:1 compression though. Not sure that makes a difference. So it's been really hard to get a stable idle in gear. When shifted into OD or reverse it wants to stall out and reverse is worse. A little pedal will help it. It also bucks and hesitates under partial throttle from a stop. Like less than 30% TPS. Goes lean up to around 17:1, and the accell pump tuning seems to have no affect on it at all. I thought it was my IAC steps, so I set those. No change. Next the TPS, got it reading 0%-0.5% at no throttle. No change. Fuel pressure, steady 60PSI idle and load. Cam setting set at 4 for wild. The trans shifts smoothly and has all gears. Responds to line pressure tuning and shift delay tuning. I don't think the trans has any issues.
It also does this weird thing at first cold start where it will idle like crap for the first 10 seconds or so, and the O2 reads over 20:1, then all the sudden it changes and the idle smooths out and the O2 starts dropping to around 14.7. Almost like it just isnt reading the O2 for a minute.
I have the idle in park at 850 or so, and 720 in gear. Is that too little? Most of my trucks are lower than that in gear, but they have smaller cams. I figured more RPM in gear would help. I'm at a loss here. None of the tuning I do seems to have any effect at all to the idle stability or drivability. The holley terminator in my chevelle is looking real friendly....
I would suggest you try cam setting 3.
Also, try adding some accelerator pump fuel to it.
So I looked into the cam settings. They are in referance to the vacuum the cam pulls. Mine pulls around 12 so I choose setting 2. It idles a little cleaner now, but still stalls going into gear. Also, the accell pump seems to respond better to taking fuel away than adding. Im starting to wonder if maybe my injectors are flowing more than I thought. They were advertised as 50lb.