Hi Guys,
I have a funny problem with an LS2
When the ignition is on and I press the gas pedal, the throttle opens 100%
When the engine is running, and I press the pedal the throttle only opens to around 30 or 40%, and feels like im driving in limp mode. Does this sound familiar to anyone?
The engine is installed in a custom truck, so it has had changes to wiring harness etc
Any help is greatly appreciated!
"LS2" is not very descriptive since there were several variations over several years. Which ECM? What did it come out of? Does it still use the same operating system it came with, or has it been changed to a different platform? If it's been changed, what flashing tool was used to do it? Did the pedal and throttle body come from the same vehicle/platform as the ECM?
The problem is we did not build this, as far as we know All is taken out of a 2005 Corvette C6
All the components should be from that car, but the wiring, and ECU should have been modified by some shop that I dont know anything about, but I do know they used HP tuners for the software.
Will it help if I upload the tune here?
Originally Posted by blindsquirrel
Post the tune? Yes please. Also would be nice to know the Service Number on the ECM (NOT the Part Number).
You may not have built it but if you're the one tasked with fixing it you're going to have to dig in and verify the parts used match what they should be.
The software used to tune is not really relevant, but if they used HPT to change operating systems... like, if the '05 Corvette E40 was damaged and they snagged a '06 GTO computer because "hey look I found an E40, slam it in there!" and then tried to do a write-entire with the file from the '05 Vette... Not Good things tend to happen. '05 E40 and '06 E40 are not compatible. And HPT cannot write all areas of the ECM (the ETC parts, coincidentally) so if the new file is from the same year but a different platform with different ETC needs and the left-behind ETC code isn't compatible with the new parts, the throttle doesn't work, or works weird, or only works sometimes...
Thank you so much for your input, have attached the read to this message
Will not have time to verify this info until monday, but I get what you are saying, and will look in to it
Thanks again for the help
ls2 pickup.hpt
The service nr = 12597191
It is a 2005 Service Number, and it has a 2005 Corvette OS on it, which is good in that the hardware is compatible. Nobody knows if it used to have something else on it; and, if it was changed sometime in the past, there's no way to find out now what tools were used to do it.
It's impossible to rule something out when it's an unknown. I hate unknowns.
If it were me, I would:
1. verify that the pedal and throttle body are correct for the '05 Corvette. If they aren't, either:
1a. get the correct parts.
1b. find out what platform the parts came from, and if they're from another '05 something, switch to a operating system from that platform. (option 1a would give much fewer headaches)
2. reflash the ECM with a stock OS using GM tools. Just take the VIN from the existing file & feed it to GM TIS.
3. get the wiring diagrams that match whatever OS I ended up with and verify pin-to-pin that every single wire in the harness is going where it's supposed to.
Only after the basics are known would I bother with checking the tune file for problems (though I don't see anything that stands out when doing a quick compare to a stock '05 Vette M6 file).
Uh oh...
I put your VIN into TIS just to look, and this is an auto trans file. Or used to be. But since the TCM is no longer present either physically or in the tune file, there could be leftover auto trans stuff still in the file that can't be got to anymore.
screenshot.19-05-2020 12.57.12.png
(if you plug in a manual trans VIN you can't get to this screen, it gives a 'VIN not found!' popup)
1G1YY24U755113676 is verified as a true manual trans VIN, harvested from a stock tune file from the repository.
well, if it was easy no one would do it hehe
but are you saying that this info can not be reached now?
So if im understanding correctly we need either the TCM and/or the original auto trans tune, to mak
Nope, just flash it with a true manual trans file with Tech2/MDI+TIS, then copy over the changes from stock in your existing file.
Appreciate it, thank you very much for helping us out!
apparently its pretty hard to get this tech2 here in Europe, and now this idea popped in my head;
Would it work if I order a manual Corvette's ECU from Ebay? they are pretty cheap as well
Sure. I'd find one of the 'programmed to your VIN' sellers though. Search for the correct Service Number, then give them the VIN I listed above.
If you have a different VIN you'd like to use, European-spec?, go to https://tis2web.service.gm.com/tis2web/ input the VIN and select 'TCM', it should give an error if it's a manual VIN. If it gives you calIDs it's an auto.
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