GMPP E67 Issues

Hi Guys, i have a problem with a GMPP E67 hot rod harness kit. I cant get rid of codes p0121 and p2101. Everytime it trips them it shut the throttle down. Everything is tuned out properly, its a procharged 408. Maf is blow threw card style and scaled, HZ are in range, scaled everything else as it makes 630 to the tire. It runs absolutly perfect, but if you hold it down too long it trips the throttle shut and goes into limp. Its got a wierd issue, if i disconnect the alt, i cannot trip it, but if i hook it back up, it trips. Its a pro street 67 Nova, with no expensce spared, and i tune for a living, so its not poor product nor lack of experiance.
Battery volts are it 14 when running, 12.2 when alt disconnected. I have shielded the drive by wire wires, replaced the new batteries with new ones, changed altornators (figuring dirty voltage), checked grounds ect ect.
I used the GMPP base file it came with as it is emission delete already, even purchased a new ECU (maybe i damaged the old?) Tried shutting them off, doesnt work. Replaced the throttle body. Even tho it looks like a alt issue it cant be. Everything is changed twice over. I tune multiple boost applications, but non of them is this GMPP Hotrod kit. Does anybody have issues with these? Should they be flashed to a normal op system and then convert the tune i have built? Would that even matter? The funny thing is that sometimes its fine with the alt hooked up.

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Originally Posted by 540sscamaro

Hi Guys, i have a problem with a GMPP E67 hot rod harness kit. I cant get rid of codes p0121 and p2101. Everytime it trips them it shut the throttle down. Everything is tuned out properly, its a procharged 408. Maf is blow threw card style and scaled, HZ are in range, scaled everything else as it makes 630 to the tire. It runs absolutly perfect, but if you hold it down too long it trips the throttle shut and goes into limp. Its got a wierd issue, if i disconnect the alt, i cannot trip it, but if i hook it back up, it trips. Its a pro street 67 Nova, with no expensce spared, and i tune for a living, so its not poor product nor lack of experiance.
Battery volts are it 14 when running, 12.2 when alt disconnected. I have shielded the drive by wire wires, replaced the new batteries with new ones, changed altornators (figuring dirty voltage), checked grounds ect ect.
I used the GMPP base file it came with as it is emission delete already, even purchased a new ECU (maybe i damaged the old?) Tried shutting them off, doesnt work. Replaced the throttle body. Even tho it looks like a alt issue it cant be. Everything is changed twice over. I tune multiple boost applications, but non of them is this GMPP Hotrod kit. Does anybody have issues with these? Should they be flashed to a normal op system and then convert the tune i have built? Would that even matter? The funny thing is that sometimes its fine with the alt hooked up.

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What color is your throttle blade? :)

What you are describing is not unusual with the '09+ brass/gold colored blade in blown applications.

It is a Brass/ gold, why? is this a issue or a problemed throttle body, if so, what do you advise using. Is there a specific year to use? I worked threw the night on the dyno, and found a patern of when applying full throttle at lower rpms (where it lugs the converter to catch up speed) it trips every time. yet if i make pulls ot drives applying full throttle at higher RPMs it seems fine even with the alt on.

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Originally Posted by 540sscamaro

It is a Brass/ gold, why? is this a issue or a problemed throttle body, if so, what do you advise using. Is there a specific year to use? I worked threw the night on the dyno, and found a patern of when applying full throttle at lower rpms (where it lugs the converter to catch up speed) it trips every time. yet if i make pulls ot drives applying full throttle at higher RPMs it seems fine even with the alt on.

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Well...its not a problem on a regular production car but once that TB gets some FI then it suffers from positioning faults. It doesnt seem to have as much torque as the earlier type. Who knows why GM changed. Also depends on which GMPP tune you have. There should be one for '08 and earlier alloy color TB's and another for '09+ TB's like you have. But not sure if GMPP has done any for the later TB. They both use different throttle controller calibrations for the different characteristics.

If you are interested post your tune and email address and we can apply a revision which may help you. :)

I am just changing the throttle body to a silver one, I have a 07 corvette here that has a silver one, and going to try it out right away, do you have a email i can send you the tune file to?

Good to know Ian, thanks for sharing that. There must be so many people getting caught out by this.

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Originally Posted by GMPX

Good to know Ian, thanks for sharing that. There must be so many people getting caught out by this.

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Yes it is a little annoying. Sometimes even turning the later TB upside down is reputed to raise DTC's. :0 Brings up a 1516 or 2101 error. Not sure what the difference is between the two as the description is very similar but I guess one has more to do with MAF rationality or something like that. :)

Cheers Ian

That was it!!! I was starting to think it was me in the tuning as i had changed throttle bodys from another motor in house. The problem is all the stuff i have is 09 and up. So i just changed to another gold one. Placing the two of them side by side the silver opens reverse. So i put it back on the dyno to check the air fuels, just to make sure nothing changed and the tune was dramatically off, perticularly at mid throttle. It changes the air flow characteristics of the intake Being the throttle blade doesnt open "100%" it redirects the air to the top of the plenume vs the bottom. Altho pressure is supposed to be the same on all areas (boosted), the flow must change. Enough to change the tune. No biggy, the numbers it put out was the same, just needed some retune. I presume they made these changes to the throttle body so there would be no chances for runaway conditions. I must thank you very much for the info. I had struggled with this for a while already. Yet in the turbo cars i do, i dont have these issues with the gold blades. It must be the turbulance of the supercharger-Quivering the blade. Thanks again.

Wow, sticky this one under odd tuning issues related to hardware..