My car/truck entered Reduced power mode, WHY!!!

[eficalibrator]

yeah im doing a hummer h2 thats stock except for a ported throttle body and im getting this???

Porting the TB changes the way air enters and flows through it. (Obviously, since this was the reason someone ported it in hopes of increasing power) However, the PCM expects to see a specific airflow at each engine speed and throttle angle.

If the ported TB flows too much more than the reference, this looks like a mechanical failure to the PCM due to a stuck open TB and it clamps down to a safer operating mode to avoid damage. An added side effect is poor idle control since it's difficult for the PCM to figure out what you did to it and why it can't get exactly the right RAF at idle for a certain blade angle.

Porting the TB rarely makes exceptional power increases and almost always leads to issues like these. I never recommend it. Instead, you can look at installing a larger OEM TB (from an LS7, for example) ONLY if you go into the calibration and update all of the appropriate ETC parameters.

[fasttrackperformace]

Look at your dynamic cylinder airflow. On the LS1 series, if you go over 2.32 g/cyl the P1514 sets regardless. You will have to fudge the VE & IFR to get the g/cyl below 2.32.

I have a TT C5 on the dyno that is making 850 ft lbs at about 4500 and goes into power reduced mode. Can you turn the code off, or is that not reccomended? I am assuming all the other changes outside of VE and IFR scaling will not fix it? TIA.

[EC_Tune]

Turning the code off will have no effect. You must reduce the IFR & VE to get where you need to be.

[fasttrackperformace]

Yeah, I have already done that and its fine. It made 1010 rwhp and 1035 ft lbs at 21 psi.

[waynehartwig]

How can you tell if you are in reduced power mode? I have a 'mode'? issue with mine and can't figure it out.

Here is the latest tune and a log from a tune I had just previous, when I was still having the problem.

[xBoostx]

I am now getting this on my LS2. Im not sure which tables to modify in the dynamic airflow table. Can someone screen shot or let me know where i have to make the changes?

Also what i think is causing it can be the idle fluctuation. The AFR's go as lean as 17 for a few seconds then back to normal

Here is the tune.

Thanks

[Bill@HPTuners]

I am now getting this on my LS2. Im not sure which tables to modify in the dynamic airflow table. Can someone screen shot or let me know where i have to make the changes?

Also what i think is causing it can be the idle fluctuation. The AFR's go as lean as 17 for a few seconds then back to normal

Here is the tune.

Thanks

my first question is why do you have the maf enabled in a speed density only tune? Also your maf codes are set up incorrectly, I'm almost suprised your vehicle even starts to be honest.

[driver240]

i reset my nick william elect trottle body and the po1120 1220 1516 1221 appear i m in reduce engine power mode ....i reflash the computer and it still is in reduce engine power....im desapointed..!!! before i reset it i think it was choked samething as the troottle was not opening to 100%

427 iron C5 , nw 102mm , fast lsxr 102 , cams 238-240,

[05HD]

Bill, I see this post is from 2007.

Is there any plans to fix this permanently with access to the correct table? The IFR workaround is a rather annoying bodge IMO.

[Bill@HPTuners]

Bill, I see this post is from 2007.

Is there any plans to fix this permanently with access to the correct table? The IFR workaround is a rather annoying bodge IMO.

There is no "correct table", from what we can tell its an issue with gm's code.

[05HD]

That is disappointing. I guess I will be doing more standalones for the FI stuff.

[Bill@HPTuners]

That is disappointing. I guess I will be doing more standalones for the FI stuff.

The issue seems to only effect a small handful of operating systems so a standalone isn't necessary and even in those operating systems the ifr scaling seems to work just fine from what we can tell.

[jakebdb56]

Bill, I see this post is from 2007.

Is there any plans to fix this permanently with access to the correct table? The IFR workaround is a rather annoying bodge IMO.

Honestly once you scale everything you regain the ability to effectively control timing in various areas whereas unscaled you'll be in the last row of the timing table (typically) and you have crap for resolution. It only takes a couple minutes to correctly scale a tune and set it up appropriately.