Express Van E78 sluggish cruise throttle responce

[curtistdc]

I am new to Efi Live but have experience from early gm fuel injection tuning 80's vintage truck stuff where you had to burn eproms. I recently had a custom tune done for my 19 Express van 6.0l so I had a starting point to work from with efi live. There was a gear change and tire size change involved. So the tune improved on throttle responce and power in certain areas but there is a problem when towing anything down the highway. You notice it when the cruise control is on and you start up any kind of hill. As the throttle advances there is very little acceleration until there is a down shift. normal highway speed an rpm would be 60 at about 1700 to 70 at about 2000. The gears changed from 3.42 to 4.11 and a tire size change from 245 75 16 to 265 75 16. the majority of the custom tune changes were with the pe tables and spark advance tables and some shift point changes.

Looking through the tables I have come across the B8305 table torque limiting, max throttle vs rpm. I am thinking maybe this could be the culprit. These are the current settings at 2000 rpm and below 37% 2000 and above 100%. Maybe I am wrong, but my brain is telling me that when cruising down the highway at these speeds I am usually stuck below the point at which it would demand more throttle unless there was a downshift. With the cruise on the van slows 5 to 8 mph before this happens. I understand that this is a setting that was used in other vehicles to prevent lugging with manual transmissions. This is an automatic so I am assuming that a downshift would eliminate that before there was a serious lugging problem.

I have not tried to change these settings yet and wanted a little feedback before I did.

I would appreciate if anyone out there could shed some light on this for me it would be greatly appreciated.

Other than gear and tire change everything is stock on the vehicle.
Thanks
Scott

[In-Tech]

Hello,
Do you have the stock files and the modified files that you can post? The e78 is an incredibly powerful ECM but does have its' peculiarities. If you can, please post stock and modified ECM and TCM files.
-Carl

[curtistdc]

Here they are, appreciate the quick response

[curtistdc]

sorry here are the trans files

[joecar]

Did it work correctly before the tune was done to it...?

[curtistdc]

It has been 8 months since I changed from the original tune on it so I can not remember. I had not towed anything with the van before i did the gear change, tire change and new tune. I did log some data the other day so I could try and see what was going on in the background. It seemed like there was a lot of spark retard throughout the driving session. I was curious being a torque based system am I seeing knock retard or torque management retard? Is the optimum tune one where there is no spark retard due to knock or are the modern efi systems fast enough that they can manage the knocks with adjustment? The spark retard was all at partial throttle, a wide open throttle run showed no retard from what I could see.
Thanks
Scott