MAF signal

[LS ROB]

This may be a silly question; but can the MAF signal have an effect on spark timing?

[07GTS]

if airflow calculations are incorrect it affects the cyl air which in turn affects the row thats used for spark timing, if thats what ur asking ? if u scaled airflow by half then the cyl air for timing will be using half the actual grams air value in the spark table

[LS ROB]

I see. Thank you. I've had a pretty weird issue for a good while where my timing flutters and i can feel it. Cant seem to figure it out just yet. Ive let someone from the forum tune it and it still does it. They seem to think its a mechanical issue. I have my doubts but I could be wrong. Here lately ive just been changing stuff just to experiment to see what does what. And today noticed that the MAF signal seems pretty jagged. May look into moving the MAF sensor to see if it helps at all.

[blindsquirrel]

Speed density.

[GHuggins]

Speed Density is the best solution in this case as fan circulating the air or even flowing through the filter element differently can cause problems. Even MAF indexing can change it - had one that was having weird idle stumbles and all I did was twist the MAF to a different orientation and it fixed it.

I thought you already tried SD though and it was still there of course you didn't have adaptives zeroed out then either.

[LS ROB]

Speed density.

I was trying my best to be able to utilize the MAF sensor but ive tried all i know to do except speed density. I'll have to give it a go it seems.

[LS ROB]

Speed Density is the best solution in this case as fan circulating the air or even flowing through the filter element differently can cause problems. Even MAF indexing can change it - had one that was having weird idle stumbles and all I did was twist the MAF to a different orientation and it fixed it.

I thought you already tried SD though and it was still there of course you didn't have adaptives zeroed out then either.

Maybe i'll give it a twist to see if that helps, then if not, ill have to try get SD dialed in pretty close and give the rest of the tune a go over. Not sure what would be best but should i try open or closed loop speed density?

[GHuggins]

Do you have variable cam timing - don't think you did - honestly don't remember. If you do it's involved, if not just do in closed loop like you would your MAF and use wideband for the PE areas.

[blindsquirrel]

MAF is only better if it doesn't do weird shit and drive you absolutely crazy trying to make it work right.

[LS ROB]

Do you have variable cam timing - don't think you did - honestly don't remember. If you do it's involved, if not just do in closed loop like you would your MAF and use wideband for the PE areas.

No variable cam. It is disabled in the tune as well. So just plot VVE vs STFT?

[LS ROB]

MAF is only better if it doesn't do weird shit and drive you absolutely crazy trying to make it work right.

I laughed way too hard at this! Touche' my man.

[GHuggins]

I personally use ltft + stft to make corrections for closed loop fueling as long as long terms are still enabled and then use EQ er for PE area. Disable DFCO and go from there. O2's should be dialed in before this point as well but they should have been dialed in with the initial idle tuning.

[LS ROB]

I personally use ltft + stft to make corrections for closed loop fueling as long as long terms are still enabled and then use EQ er for PE area. Disable DFCO and go from there. O2's should be dialed in before this point as well but they should have been dialed in with the initial idle tuning.

Ill make sure LTFT are turned back on. They were disabled previously. Will i need to copy the High Octane table to the Low for tuning?

[LS ROB]

Ok guys. I tried SD and it didn't seem to make much of a difference with the timing flutter. Ive attached the tune and the log. I would like to verify that I was in Speed Density Closed Loop since i'm still fuzzy between the different engine modes and if so; is it possible to have wires ran too close together that is somehow getting interference? This is a swap vehicle so this has crossed my mind but not sure how possible that may be.

shortsd.hpl
SD tuning.hpt

[GHuggins]

Give this one a try. You were in SD, but it's still switching between idle and drive modes. I tried to differentiate the two better in this one for you. It's still SD so you can finish dialing that in.

Plug wires shouldn't cause a problem unless you've relocated the coils and running longer wires. Poor insulation will cause spark jump if that's the case. If this one isn't any better in any way just revert back. Otherwise if it's doing it less or more - just note it...

[Cringer]

I see. Thank you. I've had a pretty weird issue for a good while where my timing flutters and i can feel it. Cant seem to figure it out just yet. Ive let someone from the forum tune it and it still does it. They seem to think its a mechanical issue. I have my doubts but I could be wrong. Here lately ive just been changing stuff just to experiment to see what does what. And today noticed that the MAF signal seems pretty jagged. May look into moving the MAF sensor to see if it helps at all.

In your log file [shortsd.hpl] is one such instance of the flutter at 3:32 in? If so, you can see Tq Mgt Adv kick in without a shift. Did you ever modify your virtual torque tables?
MMYhAH9.jpg

Either way, I would max out this section and go for another drive to see if this is the cause.
85DX7Er.jpg

[LS ROB]

[QUOTE=GHuggins;728012]Give this one a try. You were in SD, but it's still switching between idle and drive modes. I tried to differentiate the two better in this one for you. It's still SD so you can finish dialing that in.

Plug wires shouldn't cause a problem unless you've relocated the coils and running longer wires. Poor insulation will cause spark jump if that's the case. If this one isn't any better in any way just revert back. Otherwise if it's doing it less or more - just note it...[/QUOTE

This seemed to have helped! I am not sure if im taking out too much or adding too much to the VVE table. It seems like the trims are staying the same but are making a difference if that makes sense. It's like the scanner and the wideband dont agree. I'm attaching my most recent log. I am also maxing out the area that Cringer suggested since we had those maxed out before i had someone tune it. SD tuning-1.2.hpt
valley bk.hpl

[LS ROB]

In your log file [shortsd.hpl] is one such instance of the flutter at 3:32 in? If so, you can see Tq Mgt Adv kick in without a shift. Did you ever modify your virtual torque tables?
MMYhAH9.jpg

Either way, I would max out this section and go for another drive to see if this is the cause.
85DX7Er.jpg

Thanks Cringer! I have maxed out the ETC torque limit but not exactly sure on the FAST TORQUE EXIT. Do i only need to max out the Enable or the Disable and ETC tq limit as well? Also, im logging ETC, SPARK,& FUEL CUT tq mgmt but none of those are responding when timing cuts??? Forgot to add that I did mess with the tq tables a long time ago(didnt know what i was doing) but i have since copied the VT table over from a stock file.

[GHuggins]

If it helped your solution is going to be where I initially thought it was and that's in the baro tables. I also raised your BRAF off idle to more "define" your idle area airflow if that makes sense since it looked like your BRAF was too low off idle for the given gears. I think your problem the whole time has been your TB. You're basically driving it with the throttle plate barely open so the ecm is switching between idle and drive modes with very little pedal movement which is why changing the adaptive timing helped and so on only those were just covering up the problem as I stated in the previous threads. By telling the ecm the extra airflow is there by "defining" the new TB setup it's not switching as often. I added 5% to the baro table up to 1600 and then smoothed up to 2400 I think it was. You could try adding 5 or even 10 percent to the whole table. Just make sure to do the same adjustments to all 3.

I know I sound like a broken record, but Cringer's tool makes it a whole lot easier to do the VVE dial in. You can switch back to MAF and dial it back in after the fact if you like as the MAF will have better temperature control.

[LS ROB]

If it helped your solution is going to be where I initially thought it was and that's in the baro tables. I also raised your BRAF off idle to more "define" your idle area airflow if that makes sense since it looked like your BRAF was too low off idle for the given gears. I think your problem the whole time has been your TB. You're basically driving it with the throttle plate barely open so the ecm is switching between idle and drive modes with very little pedal movement which is why changing the adaptive timing helped and so on only those were just covering up the problem as I stated in the previous threads. By telling the ecm the extra airflow is there by "defining" the new TB setup it's not switching as often. I added 5% to the baro table up to 1600 and then smoothed up to 2400 I think it was. You could try adding 5 or even 10 percent to the whole table. Just make sure to do the same adjustments to all 3.

I know I sound like a broken record, but Cringer's tool makes it a whole lot easier to do the VVE dial in. You can switch back to MAF and dial it back in after the fact if you like as the MAF will have better temperature control.

multiplying all 3 Baro tables by 1.07. will report back