Friend of mine has a 2008 Tahoe presently with a LY6 6.0 and a 4L60E. Truck originally had an LMG (5.3 Flex). Has the square port LY6 intake manifold with the LMG 37 lb/hr injectors, LS3 cam, K&N intake, stock truck manifolds, stock Y-pipe + cats and factory exhaust.
Experiencing a hesitation while trying to maintain speed and you'll see the RPM dip and come back up. If you let off the accelerator, it goes away. If you ramp the accelerator moderately, you'll feel the hesitation, it'll clean up and the truck will accelerate well.
Also, the truck seems down on power from what we'd expect a Gen IV 6.0 to be. Comparatively, a bone-stock Gen III LQ4 in an 05 Tahoe with a baby cam... to us, seems to be performing better. We'd figure this truck here (2008 Tahoe) to at least be on par with that.
Posting up a of datalog and the current calibration to see if anyone has any thoughts. Thanks.
OK, got the latest calibration loaded on the truck with those two correct air values. So far truck does seem to run better, idles better. Data logged and made sure to capture cylinder airmass. Log is attached.
Some more feedback, seems cleaner/smoother when cruising around 50-60 MPH, still a hesitation around 2,000-2,500 RPM. It seems to slightly taper off once engine is warmer.
Actually I should know the answer to that is going to be 'no,' since the previous logs didn't have something as fundamental as Cylinder Airmass in there, and this latest one still doesn't even have any of the multiple throttle PIDs logged...
Yes, and to answer your question it was (or so we were told) tuned by a local place. But it has never seemed right. Hence why the involvement in trying to come on here and ask opinions.
If the cal looks that out of wack where it is hardly acceptable, please just say that. No need for the snotty answer, just trying to figure this out or if everything is the ?best it?s gonna get? and the truck just sucks.
Additionally, tried to log the same channels as I?ve been recommended to log for Gen 3 DBW. My apologies that I am not logging the correct channels as you indicated but I am trying to learn.
On my own stuff (other trucks) I?ve paid multiple tuners to tune vehicles before and have had multiple times and guarantees ?everything is fine? to then only have it corrected by another shop. I am not a tuner but just a friend trying to help a friend.
It's pretty rich down low and lean up top, according to my fuel trim graphs. But I'm not the one tuning it, so my scanner isn't set up specifically to that truck. Very little of this will be applicable to anything from Gen 3, this is torque based not airflow based. Virtual VE and Coefficients and Torque Models, rather than a plain real VE.
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