help with base tune 6.7L

[O1Z06]

I finally got to crank my new 6.8 (it only took a year) and I am looking for some tips that might help steer me in the right direction. I think there are only two sensors in their original location, everything else has either moved or is a new sensor. I think the largest changes were the ZR1 MAP, LS2 90mm TB, ID1000cc Bosch Inj MAP referenced and 1L displacement increase. All of these have been taken into account based on either manufacturer supplied data or data I found here.

Any ballpark startup air and base airflow #'s? I am modifying most of my data from a base tune 6.0L LS1B silverado and my old COS5 Z06 tune. Startup was super rich (to the point I was pegging the WB and smelling unburnt fuel). I used the spreadsheet to calc startup VE, increased startup air, increased startup AFR (these were seriously rich) and increased base airflow.

It will now crank for about 3 second and fire at which point I have to hold a steady 12% GM.APP to it to swing around 1100 to 1300 rpm. Main VE seems to be close so I'm not really worried about that yet. As soon as I let off it will die.

Does the LS2 tb require any other changes than B4349 0.0191?

[O1Z06]

It will now hold a steady idle. What made the main difference was B4349 going the other way 133%. So i set 0.0330 and reset the desired air up 18% from my old engine tune. It was starting to be ridiculous to add 40g/s desired air. I have attached my tune and log I just ran if you wouldn't mind taking a look.

Cranking still is a long way from good because I have to bump the accelerator and eventually it starts.
13809
13810

[O1Z06]

I finally got a nice startup and idle but now I'm not sure what is going on. Please see attached log at frame 5789. What is telling the idle to go to 0 degrees? Throttle response is not good as you could guess. Also IACDES_B g/s hangs so I am guessing TF?

Any help is appreciated.
13818

[O1Z06]

Everything is running great in idle, but I have found what could likely be the reason for my low tip in throttle timing and hard warm start. P0343! All my timing tables are a good 10* advance above what is being commanded.

The P0343 should be an easy fix but what burns me is I check the pins when the engine was out. I guess I'm human and just goofed on this one. I hope the fix works.

[joecar]

It will now hold a steady idle. What made the main difference was B4349 going the other way 133%. So i set 0.0330 and reset the desired air up 18% from my old engine tune. It was starting to be ridiculous to add 40g/s desired air. I have attached my tune and log I just ran if you wouldn't mind taking a look.

Cranking still is a long way from good because I have to bump the accelerator and eventually it starts.
13809
13810Increasing B4349 to 0.0340 [%/mm^2]

this is telling the PCM that the throttle area now maps to a larger TP... I'm thinking this over (trying to wrap it in my mind).

[joecar]

I finally got a nice startup and idle but now I'm not sure what is going on. Please see attached log at frame 5789. What is telling the idle to go to 0 degrees? Throttle response is not good as you could guess. Also IACDES_B g/s hangs so I am guessing TF?

Any help is appreciated.
13818I'm looking at it but I don't see the reason, I'm curious to know why...

[joecar]

Everything is running great in idle, but I have found what could likely be the reason for my low tip in throttle timing and hard warm start. P0343! All my timing tables are a good 10* advance above what is being commanded.

The P0343 should be an easy fix but what burns me is I check the pins when the engine was out. I guess I'm human and just goofed on this one. I hope the fix works.

Is your CMP sensor/relector located at the front or rear of the cam...?

[O1Z06]

I'm looking at it but I don't see the reason, I'm curious to know why...

I am almost 100% sure that it is burst knock. I haven't flashed the new tune yet but will let you know soon.


Is your CMP sensor/relector located at the front or rear of the cam...?

Cam has provisions on the rear but the block is an LS3 so I have to use the front cover sensor. The problem was the A&C pins reversed somewhere either in the extension harness or the short factory harness.

[O1Z06]

Increasing B4349 to 0.0340 [%/mm^2]

this is telling the PCM that the throttle area now maps to a larger TP... I'm thinking this over (trying to wrap it in my mind).

Joecar, have a look at this post: http://forum.efilive.com/showthread.php?837-Paul-Throttle-body-scaler&p=8011&viewfull=1#post8011

[joecar]

AH, yes, I do remember reading that a while back, thanks.