I have and they did nothing. I am tuning these in classic vehicles so that might have something to do with itOriginally Posted by TriPinTaZ
I have and they did nothing. I am tuning these in classic vehicles so that might have something to do with it
Can you verify in logs that Torque Management Advance is pulling out the timing?
Is the drive train intact that you are installing into these vehicles? (engine, trans, all sensors, ecu, tcm ?)
Well I am running the ECU and TCM. I even run the BCM sometimes. Some I have the FPCM. It is TM advance pulling the timing. On 6.2 8 speeds adjusting the TM tables do help. Doing this 5.3 swaps do nothing. From what I am seeing the axle torque is messing everything up. It thinks it is getting 1000 pounds of axle torque at idle? Axle torque should be a negative number at idle.
Right it should definitely be near zero when at idle.
Along with something else i kind of figured out...
I always tune VVE....
2016 C7 M7 Z51
Callies ultra billet crank
Callies ultra billet rods
Diamond pistons
Jhonson high speed lifters
Ported and polished headwork
Custom cam
YSi-V7
would you like to share? im on the same boat, gen5 6.2l 6l80e, in a retrofit aplication, it starts fine, then it goes to negative number, like -20, -29 :/ at idle, part throttle/wot is ok,i need to tune fueling, etc, but first time it happens to me
From what i found if you get your fueling right along with your torque, your timing will come back up.
Its pulling timine because one or more of yhose conditions.
What are your mods if any?
I always tune VVE....
2016 C7 M7 Z51
Callies ultra billet crank
Callies ultra billet rods
Diamond pistons
Jhonson high speed lifters
Ported and polished headwork
Custom cam
YSi-V7
Fueling is always the first part of the equation.. been like that since gen 3 days and before..
Once fueling is correct then you can work the Tq model.. if you do Tq model before fueling you?ll be chasing your tail
ok i see, yes i only did a base tune, my base pcm is a 5.3l the engine is 6.2L. only did a base tune to start it, didnt fixed fueling or anything yet, but was the first time it happened to me, havent tune lot of gen5 yet, it is idling at -29 , will report back, thank OP and everyone
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Fixed, in my case i went to Scan Tool and Did Clean throttle body,i think it reset the throttle body when you clean it?
On the logs when the problem was present, Throttle % was at 20 at idle, cylinder air was high, idle timing was at -29 degree, on ly did that reset and it fixed my problem, i didnt clean the throttle body tho. thanks
Last edited by castorjames; 12-03-2018 at 06:40 PM.
I wouldn?t think I would need to tune ve in a stock unmodified engine. Fuel trims are good as well. The negative spark seems to have a mind of its own
What throttle body is on the engines?
Either the 5.3 stocker or the 6.2. My current ride has a 5.3 with 6.2. I have now gotten around the negtive timing issue but had to use a 6.2 tune
What part of the tune out of curiosity?
I now idle at 15 degrees at idle and gained a ton of power. Unfortunately I could not do this with a 5.3 computer. The 5.3 computer would suck the life out of the engine and kill all timing at idle. It was not happy. I adjusted it all sorts of ways with no luck. I have a Texas speed stage 2 cam with a LT1 intake. I even fitting a 5.3 throttle body with no luck. What I found out is to leave the maf curve alone. If it is off I changed fueling in the fueling injection tables. This fixed the fuel trims and got it back to idle at 15 degrees like I wanted. I just got it working and will try on the old 5.3 computer and see if I can replicate. The maf is what screwed me up. If it shows for example -15 ltft and I fix it to 0 then I lose timing. Changing the ve did not help either. It?s something in the fuel injection settings. Once I pin it down I will post up on this. Right now I have mixed and match 6.2 settings and 5.3 settings to get it to work. Again this is on a swap. Not a factory vehicle.
For the same cam you have on a bolton 5.3 I normally lower the idle reserve torque table and the external load table. Then the timing will be between 10-25 degrees at idle. Idle is 750rpm.
With fuel trims close to zero.
Maybe the LT1 intake and throttle makes it different than my case.
any update on this im having the exact same issue mind you its on a different Engine but same exact Issue .. ive tried to lower Virtual Torque ..raise it same no change.. my STFT are wll within 3% .. it is a Maf only setup .. in the scanner it clearly shows that torque management advance is pulling all my timing at idle making it Negative.. any help would be great
take 10% percent out of your maf table around idle. This will increase your timing back
But then this will also cause your idle fuel trims to increase.
Try it and see what happens. It fixes the timing issue and fuel trims usually are fine. Even if they are slightly off you have a more critical issue fixed which is negative timing. I have applied this to all my swaps with excellent results. My Tahoe used to idle at -15!! Now it purrs around 12 degrees. I tried everything thing else with nothing helping besides this simple fix
that's not the right way to do it brother
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