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ok so im trying to help a friend get his Silverado sand rail going. It has a 6.2l escalade motor swap with ecu and a 4l80 that is full manual no electronics. Now the motor starts right up and stays running. and will rev up when you hit the throttle in park. But as soon as you put it in drive its like it has no throttle response and has no power. After looking at his tune it says that vats is still enabled, could this be his problem? it has no dtc present.
Get rid of VATS for sure. But if it's starting, likely means it's not a VATS problem.
Is the ECM still looking for a 4L60E or 4L80E automatic trans? And you have a 4L80E that is not electronic? Im not familiar with that, I dont believe GM ever made them that way (unlike the 4L60 and 700R4, they went from TH400 -> 4L80E). How does this transmission know when to shift, vacuum/TV cable? If it uses anything but a signal from the ECM->TCM then you'll need to run a manual OS in the ECM.
If it starts and runs, that means that VATS has already been disabled. If, when opening the calibration with EFILive, the VATS Patch has not been applied, means that the ECM has had VATS disabled by another tuning software - every tuning software does VATS a little differently. If this is the case, do NOT apply the EFILive VATS Patch to a calibration that has already been patched with another software.
Are you using a T42 TCM ?
As always, it is difficult to help when you don't post your tune(s) and a log of the phenomena.
ok like I said this is in a sand rail project so he had a manual valve body put in the 4l80e so he can shift it whenever. So there is no transmission electronics and no tcm so im guessing this is our problem. I will re download his tune tomorrow and upload it to this site.
Attachment 19987here is his tune
You need a ECM tune from a manual transmission vehicle..
OK, like I said, it is difficult to help without both the tune and a log of the issue occurring.
Based solely on the tune you posted, the issue appears to be that the E38 ECM is expecting a T43 on the comms line, and absolutely nothing has been altered in the ECM tune to make it compatible with a non-electric automatic transmission (essentially what the lobotomized 4L80E has become).
Also, it looks like this E38 was previously tuned with HPT (or maybe Tunercat), given the VATS Patch in use and the changes to the Alternator control.
yes found out today he had a company modify the computer with hp tuners. So I guess is there anything I can do to make it not look for the trans input? is there any stickys about this issue I can read to learn how to modify it to work? He sent out the computer like 5 years ago so the company doesn't really want to talk to him I guess.
It can be difficult trying to make things right, on a project that has evolved in an eclectic manner, without your consultation. You have three main options for success, with numerous sub-options.
1. Add a TCM, and control the automatic transmission via this TCM. This would represent the most complex (lots of wiring to add) and expensive option. This option would also require additional custom tuning.
2. Program the E38 with a manual tune. The only options for this (given that you are using a 2007 truck OS and E38) are a 2007 Corvette (LS2) or 2008 Corvette (LS3) manual tune. This programming would need to be done initially with GM equipment (Tech 2, MDI, etc.) This option would require a Corvette APP (gas pedal) and throttle body (the 2005 to 2008 silver blade type) - which are becoming quite expensive (given their obsolescence).
3. Find a good conversion tuner to make your existing tune and equipment work together harmoniously. It seems that you can find a Dyno Tuner on almost every street corner these days – but most of these people only do “airflow” tuning. A Conversion Tuner is someone who has the skills and knowledge to address issues with the overall project, including module communication, mismatched platforms, and reconfiguring inputs and outputs as is necessary.
You can always go to a company that sell standalone harness/ecm packages and buy one of their ecm for manual transmission type swaps. Psi sells them for $260.