Negative timing on boosted 5.3 on shifts (cruse and WOT mode.)

I have a 2010 5.3 6 speed that i can't figure out what its cousin the negative timing. I went through the six speed tuning class but i did not like that it say to disable the upshift torque management, and that's the only thing that would help not to get negative timing on shifts. Other thing when i go WOT timing drops and slowly starts going up. Now this a 4700+ lb's truck and would not like to disable upshift torque management, I did it once and this thing felt like it slip 3rd gear:bigshock:

It's a 5.3,boost cam on 15 to 16 lb's of boost.
Here's a log the only one i have saved because i run out of fuel pump. On this one i have the timing at 8* but only get 6* and i don't see timing till around 5800 rpm's.

since this truck has VVT, you have to look at the variable cam spark table for additional timing. but I think what you have set is enough. now the timing dip

you have minimum timing TQ MGT make changes to that table you can zero it out as it has -20

You need to go back and relook at your timing strategy. While you have your Main High Octane table set to 8 (across a very large portion, not sure why?), your adder/subtracters are applying the following changes: 1) AFR Correction -- At a commanded PE of 1.3, you will add between 4 to 5 degrees based on RPM 2) IAT correction -- Per log temp of 95 F at wot pull you will pull a full -10 degrees? This table is all -10..... should pull an increasing amount of timing as the IAT's increase (see the stock table curves) 3) ECT Correction -- At the 189 F value, minimal timing will be pulled as this table also is set to a -10 degree value from 194F and up. Same comment as IAT. 4) Variable Cam correction -- is out of play at your WOT pull cylinder charge values.

Adjust the above values to give you your desired timing and provide better control. Why do you have only 8* of timing across such a large portion of your timing table? Seems widespread and a bit low but again, this is according to what makes you comfortable and a safe tune.

As far as Shift TM, go to Trans>Torque Management>Shift Torque Factor and decrease the shift points from the factory setting of 1.0 factor to say .5. See how this effects the timing being pulled. Play with the value up (increase TM) or down (decrease TM) as desired.

Hope this helps

Ed M

I recently figured this out as I was noticing the same issue - go to the spark page and find the 'spark minimum' table. This will have values all the way to -30. I tried bumping the whole table to 5 and that was too much, kick down was too rough, I'm going to reset all to 0 and see how that feels. Give it a try.

Quote:

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Originally Posted by vetteman3

I recently figured this out as I was noticing the same issue - go to the spark page and find the 'spark minimum' table. This will have values all the way to -30. I tried bumping the whole table to 5 and that was too much, kick down was too rough, I'm going to reset all to 0 and see how that feels. Give it a try.

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In my approach. you need to get the detailed retard/adders straight first and then that table will "limit" their accumulated affects as not to pull too much out.

Ed M

Tomorrow I will make some changes And test it out.
I haven't got a chance today.

Reduce ( not disable ) the AMOUNT of upshift torque reduction applied.

This is done through the TRANS > TORQUE MANAGEMENT > SHIFT TORQUE FACTOR and the SHIFT TORQUE FACTOR ADDER .

I also set SPEED CNTRL TERMINATE to " IMMEDIATE ", I find this helps with a sloppy shift feel. I personally like a stiffer stronger shift when im boosting , and truthfully even when not in boost.

The reduction in timing is torque management reducing engine power while in shift.

EDIT :

I need to add that adjusting the spark limiter is a terrible way of controlling spark ( if your looking to stop your negative timing issue ). Reason I say this is that if all of your adders ( which can also be subtracting ) make a change to remove timing due to an overly warm day ( or a state of prolonged boost ) .. and your spark limiter is set to 5 degrees across the board ... the lowest timing you will see is 5 degrees.

Mowton is right on the money.