Hey all,
I've been street tuning this thing for a while now. It's a relatively mild/baby cam in a 416 stroker. I've got fuel pretty well dialed in. In the log attached, I turned on the MAF again, but the VE tune on the way to work this morning was +/-2% everywhere. MAF looks like it wants to be richened a tad, but this doesn't seem to be fuel related. I cleaned up my VE table and it helped a lot as i would go pretty rich on rapid RPM drops making the surge worse.
Driving home, car drives pretty well. I have constantly been fighting the car wanting to surge/stall when I clutch in while coming to a stop. Because it's a stroker LS3 in a C5, a LOT has had to be touched. Car works pretty well 90% of the time, but when it starts getting really warm, it seems to want to stall/surge.
I've attached the datalog and tune of my drive home today. It randomly stalled at 23:16 while creeping along in traffic (clutch was all the way in when it stalled, i was just coasting). Before this, it was pretty well behave with the AC on.
Any ideas? I zeroed throttle cracker and that actually helped get rid of a lot of my surging issues.
Once I started getting stopped at a lot of lights, the rest of the drive home became shitty. The car bucks a bit which you can see a bit, but that's not the question right now (can't get rid of it no matter what I do, spark, fuel, base airflow, cracker, EOIT. None of it makes a difference).
Misbehaving events in log below
Stalled for seemingly no reason: 23:16
From ~30 minutes on, it kept surging at every light until I tapped the gas pedal to help it catch itself
32:58
34:09
39:22 (2nd surge almost stalled)
41:28
42:50
44:21 (3rd surge nearly stalled)
48:54 (pretty mild)
50:09
51:36
The weird thing is if you look at the STIT afterwards, it isn't adding airflow, which makes no sense. Seems like the airflow models are pretty close. I just don't get it.
So I don't normally drive with the AC on while the car is warming up. Tried it today. Turned car on and started driving. Stit was damn near 0 at idle but once I started moving, the car would undershoot idle and surge every single light until it got warm. Why is the AC not causing an issue when car is warm but can't return to idle when warming up...
I suspect it's probably the same thing when the car gets really warm and is unable to idle as well, even though STIT at a stop claims everything is on the money.
It's frustrating because it'll return to idle normally with AC off. At idle stit is almost 0. Turn AC on while sitting still, stit still says near 0. Once I start moving and clutch back in, it misses idle, surges wildly and then when I come to a stop and stab the gas pedal to help it catch idle, it says STIT is still near zero (rather than very positive, showing it doesn't have enough air)
Any luck with this? I'm trying to tune a '04 C5 with a ls3 and btr stage 4 cam. I read your other post about the ETC scalar, I'm fighting a similar surging problem only when rolling.
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