Hey guys. I recently installed an STS kit on my '05 GMC 1500HD and got it tuned on Friday. I realize that there are advantages to going speed density and losing the MAF, but for now I just wanted to make the truck drivable, especially with the larger injectors (44#). Here is what I have run into:
1. The truck has gone into "Reduced Engine Power" mode twice. Once after the initial tune, and again today while I was accelerating to get on the highway. Both times you had to pull off of the road, cut the ignition off, wait awhile, then restart it. I thought the guy tuning the truck had this problem solved after the first time, but apparently not. Both times were under full boost or close to full boost.
2. Several codes. The first came on my way home when I hit an open stretch of road and got full boost (7lbs). I got a P0300, cylinder misfire. The next codes came at the second "Reduced Power". I got a P0068, MAF/MAP sensor throttle position correlation, and a P0101, airflow values out of range.
My truck has the LQ4 6.0 with the GT67, Alky Control, MSD Boost-A-Pump, and again 44# injectors. Any thoughts as to why the problems? Part throttle driving is fine and much better than stock. There was a flat spot in the throttle, at about 1# of boost, but he kept adding timing back to bring it back alive. Again, any help from you guys is greatly appreciated. I don't have any charts or tables from the tune to post for review. However, I am going back to him tomorrow for another round of tuning. Thanks!!

 

i think ur tunner can cut those codes off but still they should not be going off and to tune with meth is something else, IMHO i would stay away from meth. good luck does the truck studder or maybe leanin out any kr or lil ping noise???

 

I am showing zero knock on my Datamaster, and my O2 values are good. Thanks for the reply!

 

1- Your ETC table isn't set right.It has to be maxed out.Thats putting you into reduced power.

2-The misfires are either the wrong plugs(should be NGK TR6) or your flooding the motor on Meth.

3- Is the meth spraying onto the MAF wires? Shouldn't be.

 

Are you tunning with a wide band? also what program is your tunner using? I t kinda sounds like you are maxing out the maf, but you shoudn't been at only 7 psi of boost...

 

>> 3- Is the meth spraying onto the MAF wires? Shouldn't be.

I had this problem with your symptoms, and had to turn down the starting point of the Meth injection. Are you runing a meth/water mixture or straight meth?

 

I really appreciate all the replys. He is using Tuner Cat to tune it. I am running the right plugs, NGK TR6 with the right gap, which off hand I can't remember, but I gapped them to the specs STS gave me. Also, I am running 99% pure alcohol mixed with water (50/50) which is plumbed into the piping right before the elbow to the throttle body well after the MAF. Thanks again for the help!

 

>>is plumbed into the piping right before the elbow to the throttle body well after the MAF.

So is mine, but I was getting condensation or something and having a little Meth/Water running down the pipe and hitting the wire. I turned the MAS 45 degrees so the wire was not at the bottom of the tube and turned down the starting point of the injection, no problems since, even on humid days.

 

I originally thought the same but my MAF is maxed at that boost level as well. At about 5400-5500 mine maxes out at that boost level. This is why I am going 2Bar now....

 

Again, thanks for the replys. I will check the wire position and look for any moisture. On maxing out the MAF, I was told that some import cars have utilized this same MAF with 25lbs of boost, but I can't verify this. What exactly is the ETC table? I am trying to arm myself with as much info as possible before I go back to him, which appears to be Wednesday. Thanks!!