Got a strange one. I have an economy (read trans saver) tune for my 05 LLY that I have put together with stock fueling. The only thing significant I have changed is the vane position, boost, and main timing.

The tune is as follows. DSP2-off (normal) is reduced boost/open vane position at low throttle settings and a mild timing increase over stock. With DSP2 on it has stock boost/vane position but an even more aggressive main timing all for better towing.

Problem is when I flip the switch only the boost changes. Timing does not change at all. I have not actually logged any data, just used the scan dash board. Up until now my timing tables were always the same so I never noticed this. My barometric pressure is well above 14psi so I am sure it is using the C tables.

Has anyone ran into this? Any suggestions are greatly welcomed!

Try reflashing just your calibration over again on your dsp operating system see if that helps any if not recheck your different tables you had change.

Do a full flash, not the partial flash

Thanks guys, I'll try just a calibration flash again followed by a full flash if that doesn't help.

I might even just do a read and make sure the calibration is the expected one..

make sure that you adjusted b0921 in the main tables
just a thought

Thanks, good point.

With stock fueling though I am not that advanced to even need to adjust that table. Well below 20 deg.

Thanks, good point.

With stock fueling though I am not that advanced to even need to adjust that table. Well below 20 deg.

25 sounds like a good number ;)

Got a strange one. I have an economy (read trans saver) tune for my 05 LLY that I have put together with stock fueling. The only thing significant I have changed is the vane position, boost, and main timing.

The tune is as follows. DSP2-off (normal) is reduced boost/open vane position at low throttle settings and a mild timing increase over stock. With DSP2 on it has stock boost/vane position but an even more aggressive main timing all for better towing.

Problem is when I flip the switch only the boost changes. Timing does not change at all. I have not actually logged any data, just used the scan dash board. Up until now my timing tables were always the same so I never noticed this. My barometric pressure is well above 14psi so I am sure it is using the C tables.

Has anyone ran into this? Any suggestions are greatly welcomed!


Question, How do you know it's using table C? Does table C's use begin pretty far into the throttle position?

Just curious.

Question, How do you know it's using table C? Does table C's use begin pretty far into the throttle position?

Just curious.

As Yellacat said,

Timing "A" B" and "C" are used based on Baro-Pressure which is altitude.....;)

They each have temperature multipliers and in some cases they use fuel temp to alter timing......:eek:

Most trucks will use timing "C" unless you are really high up in the mountains.

Good Luck,

Tony