Humble ask for a tune check (clean up on aisle 3)

[GBull]

I've been messing around with my 01 Silverado 6.0l for years now, learning how to tune with each engine modification along the way. I ask few questions, maybe around 10 now lol, but have read and researched many hundreds. This site has many talented tuning enthusiasts for whom I owe much thanks as I quietly, lurking in the background, gleaned so much information from. I now find myself with the need to share with the forum my tune and scan for a critique. I feel the old truck runs out pretty good and the idle seems fair but with a very mild surging just around 900-1000rpms.

The old Silverado 2500HD 4WD recently received a top to bottom rebuild described below...
Molnar 3.9 inch stroker rotating assy.
10.35:1 comp
AFR 205 heads
8.1l injectors in my stock intake, all data appropriately included.
Brian Tooley's Truck Norris Cam....
K&N CAI--Really not much cold air though...
Shorty headers ... soon to be long tubers.

Feel free to be blunt, it's all good to me.
NOTE: I believe the Knock Retard that showed up is from Burst Knock. I have made many runs prior to this one with zero KR and I just turned Burst back on prior to this run thinking that I may have triggered an occasional knock sensor SES light in having it turned off...

I Thank all who take a look!

GBull (another old guy that likes to mess with everything)

[edcmat-l1]

The surging around 800-1000 RPM is the jump in timing and in the VE table. Make your timing the same up to 12 or 1400 RPM and that will take that out of the equation. Then put it in SD and dial in the lower end of the VE table using your STFT. The step from 800 to 1200 RPM can't be right.

Then after both are done if it's still surging it's due to the trims.

[Alvin]

This has too much timing at idle. The best torque idle will be 28-31 degrees but you want to save some of that torque up for a idle dip/surge etc.. I'd recommend 18 degrees as that leaves a good bit of reserve torque.

On the VE table. The 400 RPM column should be less than the 800RPM column. You likely just aren't populating those cells when you log. When the idle dips a bit I'll bet it gets rich and starts a surge.

[2xLS1]

Having burst knock turned off will not trigger a knock sensor code. Any real knock event does not set KS codes. KS codes come from a completely separate diagnostic the PCM runs on the sensors.

[GBull]

The surging around 800-1000 RPM is the jump in timing and in the VE table. Make your timing the same up to 12 or 1400 RPM and that will take that out of the equation. Then put it in SD and dial in the lower end of the VE table using your STFT. The step from 800 to 1200 RPM can't be right.

Then after both are done if it's still surging it's due to the trims.

Thank you I will work on that. This is a custom SD tune only, I decided to try eliminating the MAF since I modified the air intake system. Should I use STFT over my wideband? I have always tuned to Lambda with my wideband...

Again, thanks

[GBull]

This has too much timing at idle. The best torque idle will be 28-31 degrees but you want to save some of that torque up for a idle dip/surge etc.. I'd recommend 18 degrees as that leaves a good bit of reserve torque.

On the VE table. The 400 RPM column should be less than the 800RPM column. You likely just aren't populating those cells when you log. When the idle dips a bit I'll bet it gets rich and starts a surge.

Thanks, I'll run with your suggestion on the timing. It will take me a day or too to readjust the idle airflow numbers as I like to start from dead cold, but I will report back.

[GBull]

Having burst knock turned off will not trigger a knock sensor code. Any real knock event does not set KS codes. KS codes come from a completely separate diagnostic the PCM runs on the sensors.

I didn't think so either on the burst knock but I found a thread in some rabbit hole that mentioned it and thought I'd give it a try... Funny though it hasn't coded again.

[GBull]

Ha Ha.... just realized what reply with quote is all about.. Ive only been wandering this board for 10 years GEEZ

[GBull]

Having burst knock turned off will not trigger a knock sensor code. Any real knock event does not set KS codes. KS codes come from a completely separate diagnostic the PCM runs on the sensors.

The sensors are new GM, the harness is maybe a Dorman. gotta love the ghost-like intermittent problems. Any suggestions?

[blindsquirrel]

Thank you I will work on that. This is a custom SD tune only, I decided to try eliminating the MAF since I modified the air intake system. Should I use STFT over my wideband? I have always tuned to Lambda with my wideband...

Again, thanks

Speed density and open loop are unrelated. Closed loop with trims active and no MAF/speed density works great.

[GBull]

Speed density and open loop are unrelated. Closed loop with trims active and no MAF/speed density works great.

I was under the impression that with the maf failed you ran off of the low spark table and didn't get any knock learn, this is why I went to a custom SD tune that enabled both high and low spark tables...

[blindsquirrel]

Those things are true but again have nothing to do with open loop or using a wideband to tune the non-PE/non-OL regions.

[2xLS1]

The sensors are new GM, the harness is maybe a Dorman. gotta love the ghost-like intermittent problems. Any suggestions?

Set the codes to NER. That does not disable the sensors functioning. More times than not especially with new sensors they continue to function detecting knock with codes set for them. When you have a KS code the PCM will preemptively pull what ever the max value in the KR table is when you enter PE even with no real knock.

[GBull]

Set the codes to NER. That does not disable the sensors functioning. More times than not especially with new sensors they continue to function detecting knock with codes set for them. When you have a KS code the PCM will preemptively pull what ever the max value in the KR table is when you enter PE even with no real knock.

NER? Don't recognize

[2xLS1]

No Error Reported in the DTC tab.

[GBull]

No Error Reported in the DTC tab.

Ah yes thanks!