cdoggy81
06-18-2020, 07:17 AM
Hi guys,
I am in need of any tips or ideas as to how & proceed with this one as it has a lot of people stumped....
Everything started off as the following:
LS3 swap out of a 2008 Corvette into an old Trans Am.
Stand alone wiring harness from Current Performance, E38 computer & TCM to control the 4l80e tranny
2008 Corvette Operating System was loaded - OS & base files, Vats removed, no MAF, will be run in Speed Density (SD).
87mm CTS-V / Truck throttle body on top of a Holley Single Plane intake (this is to keep the look & functional shaker for the Trans Am as seen below).
Engine mods are: BTR cam 225/238 .612"/.585" 113+3, Ported WCC heads, 1 7/8" headers, 2.5" exhaust, no cats.
Car started up pretty easy at the builders for the first time with no major issues, just pig rich so all we did was drive it around the complex a bit to make sure everything was working properly & mechanically safe to take it to get tuned. Got the car in to the tuner finally & was able to to start the process. We get all the basic parameters adjusted, set it to fail the MAF on startup & started working the SD tables. Started right up after the re-flash & even idled better so we took it for a run to start filling in the tables. Got back to the shop to load some more info & she would not start again after turning it off. After a lot of back & forth (thinking it was a fuel pump, maybe wiring or a bad ground, bad computer, etc.) we determined that the corvette OS did not like the fact that we had an 87mm truck TB on there vs the stock 90mm corvette one. When I got her back home on the trailer & the next day put the stock corvette TB back on the problem was solved. Started up every time, idled good, drove around good (nothing fast or hard).
Brought the car back to the tuner & he loaded a truck OS overtop of the corvette so it would now work with that TB but as my luck goes it bricked the computer.... :l So now I have to buy a new e38 computer from the dealer & have it all setup from the start for a 2012 Silverado. At least we now have a clean slate & correct base OS to work from.
Back at the tuner everything is working good with the new e38 & base OS, it is taking all the changes & file adjustments he is throwing at it in HP Tuners. All is looking good until we start doing wide open pulls. When we go WOT the car goes into protect mode every time. We reset everything & try it again but this time by rolling into the throttle & it seems like once you hit a certain RPM (say 4500+) or throttle position (like 2/3 open +) it goes into protect mode. Tuner asks out of the blue if the TB has been modified bc sometimes over ported ones cause problems. Sure enough I said yes this is a ported TB out of a CTS-V. He said that maybe causing the problem so we decide to buy a brand new 87mm truck TB for the 2012 Silverado just to be safe as it should fix the issue... :l
TB comes in & a few days later I am back at the tuners. We put the new TB on., she starts right up, we take it out to start tuning again & same issue, limp mode at WOT!!! It didn't fix anything.
Does anyone have any ideas as to what could be causing it to go into protect mode? What are we missing as I am at the end of my my rope here... Thank you all very much for any help or direction!
I am in need of any tips or ideas as to how & proceed with this one as it has a lot of people stumped....
Everything started off as the following:
LS3 swap out of a 2008 Corvette into an old Trans Am.
Stand alone wiring harness from Current Performance, E38 computer & TCM to control the 4l80e tranny
2008 Corvette Operating System was loaded - OS & base files, Vats removed, no MAF, will be run in Speed Density (SD).
87mm CTS-V / Truck throttle body on top of a Holley Single Plane intake (this is to keep the look & functional shaker for the Trans Am as seen below).
Engine mods are: BTR cam 225/238 .612"/.585" 113+3, Ported WCC heads, 1 7/8" headers, 2.5" exhaust, no cats.
Car started up pretty easy at the builders for the first time with no major issues, just pig rich so all we did was drive it around the complex a bit to make sure everything was working properly & mechanically safe to take it to get tuned. Got the car in to the tuner finally & was able to to start the process. We get all the basic parameters adjusted, set it to fail the MAF on startup & started working the SD tables. Started right up after the re-flash & even idled better so we took it for a run to start filling in the tables. Got back to the shop to load some more info & she would not start again after turning it off. After a lot of back & forth (thinking it was a fuel pump, maybe wiring or a bad ground, bad computer, etc.) we determined that the corvette OS did not like the fact that we had an 87mm truck TB on there vs the stock 90mm corvette one. When I got her back home on the trailer & the next day put the stock corvette TB back on the problem was solved. Started up every time, idled good, drove around good (nothing fast or hard).
Brought the car back to the tuner & he loaded a truck OS overtop of the corvette so it would now work with that TB but as my luck goes it bricked the computer.... :l So now I have to buy a new e38 computer from the dealer & have it all setup from the start for a 2012 Silverado. At least we now have a clean slate & correct base OS to work from.
Back at the tuner everything is working good with the new e38 & base OS, it is taking all the changes & file adjustments he is throwing at it in HP Tuners. All is looking good until we start doing wide open pulls. When we go WOT the car goes into protect mode every time. We reset everything & try it again but this time by rolling into the throttle & it seems like once you hit a certain RPM (say 4500+) or throttle position (like 2/3 open +) it goes into protect mode. Tuner asks out of the blue if the TB has been modified bc sometimes over ported ones cause problems. Sure enough I said yes this is a ported TB out of a CTS-V. He said that maybe causing the problem so we decide to buy a brand new 87mm truck TB for the 2012 Silverado just to be safe as it should fix the issue... :l
TB comes in & a few days later I am back at the tuners. We put the new TB on., she starts right up, we take it out to start tuning again & same issue, limp mode at WOT!!! It didn't fix anything.
Does anyone have any ideas as to what could be causing it to go into protect mode? What are we missing as I am at the end of my my rope here... Thank you all very much for any help or direction!