Rebuild Runs Rough

AJ/FormS said
Ohchit :(;wrong thread

then back to post 17, for same ending.

I back calculated your total chamber volume from the 9.15 previous Scr and added your estimated 4cc increase to re calculate your Scr to 8.62
I calculated your swept using a 3.94 bore
I grossed your 218/218/115 hydraulic roller cam up by 52 degrees to get a cam with advertised specs of 270/270/115,which, in at 113, equals an ICA of 68 off the assumed advertised.
I plugged in 6150 altitude
The overlap works out to 40* using the assumed advertised specs.

Static compression ratio of 8.62:1.
Effective stroke is 2.47 inches.
Your dynamic compression ratio is 6.68:1 .
Your dynamic cranking pressure is 97.76 PSI.
V/P (Volume to Pressure Index) is 71

This does not match your 110/120 psi, so I assume some erroneous input(s), on my part. But the point is the same; she has a fairly late-closing intake angle, which means the intake manifold, at idle, is gonna be full of air going everywhichaway, which, if the injection timing is too early, will pump a lot of fuel back up into the intake, driving your AFR crazy. If you can, put the computer into open loop, (oh I see you did), and richen her up, and inject as late as you can, to dry up the intake and avoid that backflow.

Hmm, I see what you mean now. Mega squirt 2 is set up as a batch fire style injection, meaning it squirts one bank, then squirts the other, 360 crank degrees apart. Unfortunately, it’s not sequential and I don’t have much choice other than timing each batch, which would make it great for some cylinders, but the others not so much.

I started it up between rain storms and first looked at my tooth logger, which I can see every tooth and the missing tooth on display in the tuning software. Everything looked normal. I was able to enrich the mixture and it seemed to like it, I noticed I had a lot better throttle response. I believe a lean condition is mostly at fault here. Thanks to everyone who has chimed in.

I must have made too many adjustments at once to the ignition, fuel, and warmup because my laptop started to lag, the interface threw a fit, and it pegged full rich without commanding it and ran very rough. I couldn’t correct it, either, even after making a drastic lean adjustment. I let it die. I couldn’t restart and decided to let it cool off. I think I’ll have to just start all over with the fuel/ignition maps when I have more time.