Help with TUNE

[Chris miller]

Can someone please help me?
1999 GMC Sierra 1500 2wd

Gen3 5.3L .020 over
Flat top OE style 4.8 pistons with LQ9 rotating assembly\
706 heads, LS9 head gaskets, ARP studs, PAC 1219 springs, pushrods, trunion rockers, etc.

8.1l injectors (42LB)
8.1l fuel pump to match flow of injectors
stock 5.3l fuel pressure regulator

Cam is Tick torqueMAX stage 2

211/217 .535"/.527" LSA 113+3

Operating range idle to 5500rpm

2300stall installed in mild build 4l60e. right now rear gearing is 3.42 AND will be installing 4.10 as soon as I get the time.

I know he has knock disabled and i believe due to the false knock of the header slightly touching the passenger side frame.
I know he has MAF disabled or did until i took it back to him yesterday to fix cold start up. it would start cold but wouldnt "wake up: until it reached 110 degrees, then it would run fine.

When i got back to him yesterday, he said he added something to cold start enrichment and it was fixed..... i got out here this morning to see and its 100X worse and wont even run normal even after 110 degrees. I have an MPVI2 and have pulled both files before and after he changed it... I purchased credits and reloaded the original faulty file just to make it run.
With the original tune, the truck made 305.1hp to the wheels on the dyno.


Attached are both files, the original the tuner initially did and the second is the one he changed yesterday.

original and final are the same tune and the modified is the same.

99_Sierra_original.hpt
cold_start_final.hpl
99_Sierra_modified_1_11_25.hpt
cold_start_modified.hpl

[04silverado6.0]

That was pretty bad. I have fixed a lot of wack tables including injector data. I would treat this as a new startup file. Spark table is dyno proven.

[04silverado6.0]

Also, is there any reason for open loop operation? You can put this into closed loop and tune with stft.

[Chris miller]

i will load this here shortly and do a log. waiting on ECT to drop below 100

[Chris miller]

Also, is there any reason for open loop operation? You can put this into closed loop and tune with stft.

i asked him the same question about closed loop, he did some things and it started to run like crap. Im really really new at all the tuning stuff. i have an L5P and im scared to load the SOTF parameters because i might mess up lol

[Chris miller]

i will load this here shortly and do a log. waiting on ECT to drop below 100

loaded the file and waiting to drop ECT. its at 113 right now. I think some of the issue is with the "ghost cam" as he called it. tbh, i dont really care for it.

[twenglish1]

Copied the primary VE into the secondary.

99_Sierra_original edit 1 - Primary VE Copied into Secondary.hpt

[04silverado6.0]

Copied the primary VE into the secondary.

99_Sierra_original edit 1 - Primary VE Copied into Secondary.hpt

thanks for catching that

[Chris miller]

thanks for catching that

I?ll load as soon as I get home and log. Temp should be well below 100

[04silverado6.0]

Make sure to load the new one with the secondary ve matching the primary.

[Chris miller]

I will.

[Chris miller]

99Sierra_v1_log.hpl

Here's the log for the last run. still doing the same thing. Am I doing something wrong? Anything I need to do before starting?

[twenglish1]

Might help to re-enable closed loop and STFT in open loop

99_Sierra_original edit 1 - Enabled Fuel Trims.hpt

Add Bank 1 and 2 short and long term fuel trims in VCM Scanner

[Chris miller]

How do I do that? The re-enable etc

[twenglish1]

I did it for you in that file posted above, I also fixed the MAF DTCs to properly fail the MAF sensor, there was no code on the last log indicating a failed MAF. Under Engine>Fuel>Oxygen Sensors there is the ECT vs. IAT table, the LTFT enable switch, and the LTFT minimum ECT, then under the Open Loop/Base tab there is the STFT Open Loop switch set to enable. I also set the open loop EQ table to go to Stoich as the engine warms up.

[Chris miller]

I did it for you in that file posted above, I also fixed the MAF DTCs to properly fail the MAF sensor, there was no code on the last log indicating a failed MAF.

Loaded, added to scanner but won?t run

[Chris miller]

99Sierra_v1_log1.hpl

[twenglish1]

Hmm so it must have actually been running on the improperly disabled MAF sensor. What throttle body are you using?

[Chris miller]

stock lm7 tb. biggest issue is the cold start idle etc. it runs fine after it gets to 110 degree.

[twenglish1]

Im still not seeing the MAF DTC on the log, also do you have a wideband installed?