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need MAJOR COMPUTER HELP for my LS3 swap in speed density
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!
Pics below are for reference so you can understand the setup, why SD & no MAF plus why I had to use the compact 87mm TB vs the 90mm corvette one (won’t fit under an air cleaner).
Thanks
Last edited by cdoggy81; Jun 19, 2020 at 12:00 PM.
I'm not sure why you went with the later computer stuff vs earlier cable driven stuff. I've seem lots of issues like this out of the later stuff on swaps. If you have the wrong throttle body for this ecm, it will do that. You could have two identical tb's and the blade opens a different way, it will go into limp mode. there probably codes that need to be deleted that arent.
BC I Had a complete corvette engine, didn’t want to mess with converting to the 24t wheel as the benefits outweighed The negatives plus I never thought I would ever run into all these problems with DBW GM stuff
what really stumps me is I have a new computer for a 2012 Silverado, The OS loaded for a 2012 Silverado, a new 2012 Silverado TB & it is still fubar!
Last edited by cdoggy81; Jun 18, 2020 at 07:41 PM.
There is a table in the diagnostics that sets max delta maf vs SD and puts you in limp mode if you fall outside that error. There is another that sets error on commanded vs actual tps. Likely you need to increase both tables to avoid setting the error.
Thank you very much Darth! I will run that by him! I did get a message to look for a p2135 (maybe another code?) as one of his wires in the throttle body grounded out & causing problems.
Another was to max out the default transmission TM table that is located in the Engine TM tab. If you are running an aftermarket TCM, or a manual transmission, it will shut your throttle at 4k rpm. Verify it is a 2wd cal file on the new e38 OS.
Again, thank you all very much for any & all suggestions. This is costing a ton & causing me a huge headache for something that was to be such an enjoyment after so many years of building :-(
Please tell me this is not the case... They used the 4l80e up to 2013 in the trucks & the tuner said the E38 EMC would work with the T42 TCM which is why he loaded a 2012 Silverado OS. Are you saying he should have loaded something like a 2007 OS from a express van??? (basically something with a V8 & 4L80e from the factory)
Please tell me this is not the case... They used the 4l80e up to 2013 in the trucks & the tuner said the E38 EMC would work with the T42 TCM which is why he loaded a 2012 Silverado OS. Are you saying he should have loaded something like a 2007 OS from a express van??? (basically something with a V8 & 4L80e from the factory)
It all depends on the service number of the E38, that dictates what calibration you can flash into. All E38's look the same but there are 4 or different service numbers. For example if you took a 2013 E38 for a 5.3/6l80 silverado and flashed it to a 2007 E38 for a 5.3/4l60 it would not work. You also have to flash new E38's with SPS (GM software) with a calibration before using hp tuners on it. You can defiantly run an E38/T42 and make it all work with a 4l80 you just have the correct ECM/TCM and correct OS in the ECM and TCM.
After the first e38 was bricked we went to the dealer & got a brand new e38 for a 2012 silverado & had it loaded with the correct OS & files for that 2012 silverado as well as a new throttle body for a 2012 silverado. That way we know everything was set up from the start as a 2012 silverado.
I assume what we need to do is verify what powertrain package was loaded on the new computer for the 2012 silverado. 5.3/6l80. 6.2/6l80, 6.2/4l80, etc.
A 2012 silverado E38 should be service number 12633238 which as far as I know is only good for E38/T43 (6l80/90)setups and wont work with E38/T42 (4l60,4l80).
Well that's a bummer :-( I'll verify what computer was ordered. I appreciate you looking that info up & helping out.
I will say right now it runs & drives great all over town as long as you don't floor it or go over ~4000 rpm or so. Goes through all the gears fine, downshifts, up shifts, lockup, etc. Heck on a private airstrip I was able to cruise at 115mph for a bit with the AC on & she ran great.
BTW I did just hear back from the tuner & another reason this is so frustrating is bc it is not throwing any DTC's! We are going to go back through & verify the entire OS did in fact make it onto the PCM.
Also airflow limits are maxed as airflow diagnostics are disabled when he does a new camshaft tune.
Well that's a bummer :-( I'll verify what computer was ordered. I appreciate you looking that info up & helping out.
I will say right now it runs & drives great all over town as long as you don't floor it or go over ~4000 rpm or so. Goes through all the gears fine, downshifts, up shifts, lockup, etc. Heck on a private airstrip I was able to cruise at 115mph for a bit with the AC on & she ran great.
that doesnt sound so great to me, lol.
Originally Posted by cdoggy81
BTW I did just hear back from the tuner & another reason this is so frustrating is bc it is not throwing any DTC's! We are going to go back through & verify the entire OS did in fact make it onto the PCM.
Also airflow limits are maxed as airflow diagnostics are disabled when he does a new camshaft tune.
If you have the wrong OS or a miss-matched OS if will most likely never throw any codes. It will pull timing and or close the throttle when you try to get on it. We have had several swaps drive to us and not know they had a problem because they hadnt drove it hard enough. Then we put it on the dyno and it wont do a full pull. We checked the tune and ecm/tcm combo now on a swaps before putting on dyno when possible. (sometimes cant physically get to ecm/tcm).
When doing a swap the easiest way to ensure you have a combo that works is just order your harness and ecm/tcm all from Speartech. It will save you from many headaches and added expenses down the road.
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need MAJOR COMPUTER HELP for my LS3 swap in speed density 
They used the 4l80e up to 2013 in the trucks & the tuner said the E38 EMC would work with the T42 TCM which is why he loaded a 2012 Silverado OS. Are you saying he should have loaded something like a 2007 OS from a express van??? (basically something with a V8 & 4L80e from the factory)