chpspecial Posted January 6, 2012 Report Share Posted January 6, 2012 Long shot here, but does anyone have any insight on a P0068 code???? Quote Link to comment Share on other sites More sharing options...
silverado777 Posted January 6, 2012 Report Share Posted January 6, 2012 (edited) Could be caused by a vacuum leak or faulty MAP or Throttle Position Sensor. Done a work on it lately? Might have pulled of a vacuum hose? Edited January 6, 2012 by Silverado777 (see edit history) Quote Link to comment Share on other sites More sharing options...
chpspecial Posted January 6, 2012 Author Report Share Posted January 6, 2012 I understand its a MAP/throttle body correlation problem... Yes it has a new 2 bar MAP sensor, but I can assure you it is not vacuum leak, and the MAP sensor is reading properly... I too am leaning to a faulty TPS as the truck is very jerky at light throttle Quote Link to comment Share on other sites More sharing options...
Cramer Posted January 7, 2012 Report Share Posted January 7, 2012 I am betting its the TPS also. My buddy with a rear mount just had the same issue and code. The spring in the TB was getting weak from boost. But the weird thing about this is that he just out a new 2 bar map in also. Either way he had another tb and we put it on and cleared the code. Didn't come back again and that was about a month ago. Quote Link to comment Share on other sites More sharing options...
chpspecial Posted January 7, 2012 Author Report Share Posted January 7, 2012 (edited) Nick Williams seems to think that its in the tuning. My logs do not show the TB closing when the code sets, however I am leaning towards a bad TPS sensor or TB, either way the TB needs to come out. I will try another good TB and go from there. Edit: Every possible thing has been tuned out and still the same code..... Edited January 7, 2012 by chpspecial (see edit history) Quote Link to comment Share on other sites More sharing options...
Sik-rod-yo Posted January 7, 2012 Report Share Posted January 7, 2012 Dam problem child! Quote Link to comment Share on other sites More sharing options...
detjoe Posted January 8, 2012 Report Share Posted January 8, 2012 did you try and bench test the TB with a volt meter to see if you can force it to give you a shitty voltage?? I hate bad parts Just went thru this with a project and I was running into crap and it ended up being my 'new' part. good luck Quote Link to comment Share on other sites More sharing options...
chpspecial Posted January 8, 2012 Author Report Share Posted January 8, 2012 Thanks Joe, That is another thing I will try. Next I am going to swap out the 02 TAC module and speartech harness for a 2004 TAC module and Xlink and see what that does. IF it doesn't fix it, then I will bench test the TB. The thing is that the truck still did teh P0068 when I swapped in my 90mm TB. So I doubt its the TB. Quote Link to comment Share on other sites More sharing options...
chpspecial Posted January 12, 2012 Author Report Share Posted January 12, 2012 After swapping TB, tac module, wire harnesses, map sensors and the obvious vacuum leak, I'm down to what might be a bad pcm. sent from my thunderbolt Quote Link to comment Share on other sites More sharing options...
detjoe Posted January 12, 2012 Report Share Posted January 12, 2012 I have been meaning to look this up on HPT.com and see if there is any help for you...but the kids just started hockey and I have this problem (I forget tuning in the winter ) thanks for the update, hope it is a simple part swap Quote Link to comment Share on other sites More sharing options...
Krambo Posted January 12, 2012 Report Share Posted January 12, 2012 (edited) Had an issue once with this code, and coincidently on a boosted motor (magnacharged 6.0L). Now you just may have a faulty TB (weak spring) however using HPT, I simply increased the entire "Calculated Airflow vs. TPS vs. RPM" (P1514/P0068 error) table by 40% in the lower TPS area and 20% in the higher. Not sure what table that correlates to in EFI Live. Is this the right way to do it, not likely but it worked for me. Edited January 12, 2012 by Krambo spelling (see edit history) Quote Link to comment Share on other sites More sharing options...
chpspecial Posted January 12, 2012 Author Report Share Posted January 12, 2012 (edited) Had an issue once with this code, and coincidently on a boosted motor (magnacharged 6.0L). Now you just may have a faulty TB (weak spring) however using HPT, I simply increased the entire "Calculated Airflow vs. TPS vs. RPM" (P1514/P0068 error) table by 40% in the lower TPS area and 20% in the higher. Not sure what table that correlates to in EFI Live. Is this the right way to do it, not likely but it worked for me. I increased those values from the beginning anticipating a similar issue... and even after maxing out all the table, I still get the code, but only in SD mode. When fueling by MAF I don't get it. Today I will swap pcms and see what happens. Edit, for got to mention, that the code came with both the NW 102mm TB and a stock LS2/7 TB. I know both are good, and the ls2/7 has been on my truck seeing more boost than the kenne bell has put out with out issues. Edited January 12, 2012 by chpspecial (see edit history) Quote Link to comment Share on other sites More sharing options...
zippy Posted January 13, 2012 Report Share Posted January 13, 2012 Are you seeing more than 2.41 DCA? Quote Link to comment Share on other sites More sharing options...
chpspecial Posted January 13, 2012 Author Report Share Posted January 13, 2012 Are you seeing more than 2.41 DCA? Can you elaborate on 2.41 DCA, I'm not sure I am monitoring that, but I will as soon as I figure it out and see what its doing. Quote Link to comment Share on other sites More sharing options...
zippy Posted January 15, 2012 Report Share Posted January 15, 2012 If your dynamic cylinder air reading is over 2.41 you are beyond the hard coded limit in the pcm. There is as always a way around it though. Quote Link to comment Share on other sites More sharing options...
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