going lean strange glitch at 5200 rpm for a split second

[davez28]

Just checked - Chris was right - the MAF isn't even failed according to the current tune settings and MAF setup...

Yes the MAF was failed and I had the codes set to verify. The tune I posted was put back because I was done SD tuning

[GHuggins]

I had a feeling that would be the case Ed The dip in the MAF is right where the problem is, but like I said it's not going to cause a complete fuel cut like this... I do wonder though, since it looks almost like it's going into DFCO - have you tried just completely unplugging the MAF and seeing if the problem is present? Theoretically it should still be, but then again?

I've only ever seen it one other time on a GM platform, but I have seen weird random fuel cuts like this when the ECM's cal was corrupted by a different AM programmer...

[davez28]

just to clarify this is the tune that was in the truck when the 5200 rpm log was taken

[davez28]

I had a feeling that would be the case Ed The dip in the MAF is right where the problem is, but like I said it's not going to cause a complete fuel cut like this... I do wonder though, since it looks almost like it's going into DFCO - have you tried just completely unplugging the MAF and seeing if the problem is present? Theoretically it should still be, but then again?

I've only ever seen it one other time on a GM platform, but I have seen weird random fuel cuts like this when the ECM's cal was corrupted by a different AM programmer...

i have owned the truck since it was new and has only ever been flashed with hpt.

[GHuggins]

It's still possible even with hpt to get a corrupted upload - even happens at the dealer level with dealer level tools - this is why they specify certain particular ways of doing things now to their techs... All it is are 0's and 1's and a minor voltage change can sometimes alter those perceived digits I'm still interested to see if the problem is present with the MAF completely unplugged?

[davez28]

Just checked - Chris was right - the MAF isn't even failed according to the current tune settings and MAF setup...

I had a feeling that would be the case Ed The dip in the MAF is right where the problem is, but like I said it's not going to cause a complete fuel cut like this... I do wonder though, since it looks almost like it's going into DFCO - have you tried just completely unplugging the MAF and seeing if the problem is present? Theoretically it should still be, but then again?

I've only ever seen it one other time on a GM platform, but I have seen weird random fuel cuts like this when the ECM's cal was corrupted by a different AM programmer...

What dip in the MAF curve are you referring to? The tiny dip at 10650 my EQ error is pretty much dead nuts through there. The dip up by 11250 is pretty much at the end of my usable range. I barely touch that cell up there.

[davez28]

Just checked - Chris was right - the MAF isn't even failed according to the current tune settings and MAF setup...

I had a feeling that would be the case Ed The dip in the MAF is right where the problem is, but like I said it's not going to cause a complete fuel cut like this... I do wonder though, since it looks almost like it's going into DFCO - have you tried just completely unplugging the MAF and seeing if the problem is present? Theoretically it should still be, but then again?

I've only ever seen it one other time on a GM platform, but I have seen weird random fuel cuts like this when the ECM's cal was corrupted by a different AM programmer...

It's still possible even with hpt to get a corrupted upload - even happens at the dealer level with dealer level tools - this is why they specify certain particular ways of doing things now to their techs... All it is are 0's and 1's and a minor voltage change can sometimes alter those perceived digits I'm still interested to see if the problem is present with the MAF completely unplugged?

Honestly that's kind of what I was thinking it was going on. I just woukd like to know if it is and if I should just get the dealer to reflash it or get a new ECM. I'd rather be taken care of. My local dealer is pretty cool .they'll only charge me $50 to reflash it or flash a new one if I buy a new one.

[GHuggins]

This is just to clarify and as previously stated not the cause of your problem - your issue - as seen from cause and effect point of view is happening at 11,100ish hz on the MAF curve - this is just before a very slight dip - again NOT the problem, but something I thought worth noting / It also starts - at least in the SD tune - at 5400 rpms as shown by the immediate timing throw in... All of this doesn't appear to be tune related - looks like something corrupted or a MAF input still at play even though it was failed... Posting some screen shots to clarify what I'm trying to say as I know I don't always come across clearly

Me personally - I would unplug the MAF - take it completely out of the picture and see if the problem is present... If it is - you might - which this usually works - but you can try going back to your very originally read OE tune - copy over your differences table by table - not copy all differences - save into a new file - then do a write entire and then see if the problem is present... If it's still present at that time then you'll need the dealer reflash and go from there...

[davez28]

I'm thinking maybe going the route of just having the dealer reflash it. Then building my tune back up off of it. At least then I would be doing something different that might fix it. Problem is I might do 20 wot runs before it shows.. as stated this has been happening during the tuning process so I have several wide open pulls then a reflash and then a bunch of pulls again and then a reflash ect..ect.. it just sucks I hate to keep beating the hell out of it without changing something that might correct it.

[01SLPSSM6]

Bump... Did you ever figure out what was causing the random lean condition? I have been searching and searching and have the same exact problem on a 2011 Camaro E38 with twin turbos. You can do a bunch of WOT pulls and it runs great every time, then all of a sudden it will hit about 5,000 Rpms and it will cut fuel, fuel pressure does not drop. After the problem finally happens, it will do it every time you get into boost for the duration of the drive. I logged torque management and the trans torque management is enabling right before it happens. Seems like the only time it happens is in 1st gear. Highway pulls in 2nd and 3rd gear are fine. Going to adjust the trans torque management settings and see what that does. Ill update the thread with my findings.